Breaking Bad "Yeah Mr. White! Yeah Science!" Scene



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From episode seven of the first season titled, “A No-Rough-Stuff-Type Deal”

Methods of Purification of Organic Compounds, 12th Chemistry for JEE Main Adv in English | Misostudy



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Check out the online video lecture of Methods of Purification of Organic Compounds – Distillation from chapter Purification & Characterization of Organic Compounds of Chemistry class 12th for JEE Main Advanced preparation prepared by Misostudy’s expert faculties. (

Organic compounds are obtained from natural resources. When these compounds are obtained, they are in their impure form. Hence, several methods of purification of organic compounds, they are sublimation, crystallization, distillation, differential extraction, chromatography.

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hello students welcome to the chemistry sessions I hope everybody is doing great so are you enjoying the techniques that we are doing in the last session we had started off with yes crystallization we had discussed crystallization and relives crystallization along with the simple distillation so I hope everybody has revised all the concepts so what we were doing in this simple distillation before moving on to that I'll just write down what all techniques we have covered we have covered the sublimation right I hope everybody remembers this we have covered the crystallization in the last session crystallization right what else the recrystalization also known as recrystallization here and what else we had started off with a very very simple procedure that is of distillation so I have got a simple one so I've got a simple distillation I have got what kind of distillation I hope everybody has a read it or not so every time whenever I give you homework you need to go through the concept first because that would be pretty easier for you to then follow up the session so here simple distillation we have got we have got fractional distillation right distillation every time I am writing down the incorrect spelling what else we have got we have got reduced pressure it's a very very interesting technique reduced pressure distillation and the last one is what kind of distillation the steam distillation also very popular so as we have discussed about the simple distillation in the last session so what actually the simple distillation is we just boil off the mixture of compounds which are having so here main thing is the boiling point difference must be sufficient enough must be enough that is around 50 to 70 Kelvin an approximate value I'm telling you telling you about so that is the minimum kind of boiling point difference that must be there there why there must be a different difference in the boiling point because if the boiling points are nearby or closer to each other and we have taken up let's just say we have got a round bottom flask here and we take up the mixture let's say of compound a and B 1 is having let's just say a boiling point of 105 degree Celsius and other one is having let's say 1 1 5 degree Celsius so what is the possibility over here the possibility is if we try to boil off the compounds they might be boiling off together and there will be no use of then this technique because it won't be separated we will be getting a vapors which is a mixture of the two again so again we are back to square one we are back to the same position again we need to separate it out via some other technique so that is why we need compounds which are having a difference in the boiling point and what are those compounds can you give me an example so it's ether and ether and toluene that is also mixture they have got sufficient enough difference of boiling points so ether and toluene I've got hexane and Halloween and also I've got a very popular mixture that is of chloroform and aniline so that is also a mixture which is separated so these are some kind of mixtures which are actually separated wire this technique because these mixtures have got sufficient enough difference between the boiling points so I hope everybody's clear with the fact now let's just move on to the fractional distillation we are through with the simple one so let's just move on to the fractional so again we'll be drawing the structure first we'll be drawing the apparatus first then I'll explain you so what is actually the fractional distillation in fractional distillation so basically what we do is we implant we actually put a fractional waiting column fractional ating column we have got a similar kind of an operator that is we take up our B that is the round bottom flask what else we take up we take up a wire goes on which it's kept right so that is the wire goes on which the RB has been kept clear what else we have got we have got a tripod stand so here we have got a stand like that and a burner so we have got a burner also so that is how the burner would be so just draw with me simultaneously so that you have a practice of it so a similar kind of procedure we are following up and what else now here comes the fire we light it up so that is the fire that is the flame we have got and what else we have we have the RB and the RB has got a mixture of compounds here so it has got a mixture of compounds so here is the liquid that we have taken up fine here is the liquid again what do we have we have got a stop called we have got a stopcock over here it's always orange in color orangish red even if you see these in laboratories so that is stopped pork here and what else we have got a tube which is penetrating inside the core and then going inside the round bottom flask so that is our B we name it as RB flask nothing but the round bottom flask what will happen there is a tube inserted in here but not a tube exactly over here what is the difference between the simple distillation and the fractional now we'll see here so here we have got is a column we have got a column over here that is the column that is this is the column over here and here it's again of stop cork over here the column has got something in it let us just see what is that so it has got some weeds in it some crystals in it so these are the kind of beads which are present which are actually what the beads are doing whenever the liquid boils off so whenever the liquid boils up from the round bottom flask it goes into the fractionating column it has got so many kinds of glass bead that the surface area or the traveling time of that vapor increases and that means what those kind of liquids which are having the closer boiling points will actually be separated very efficiently via this technique so what is happening here is let me just draw more some more glass plates over here now that is how the glass beads are so these are glass beads increasing the surface area basically what will happen the liquid will then again boil off goes into the condenser gets condensed and finally into some kind of container we have got so what is that container that container will look like somehow like this it may be a conical flask that we can take up like that so that is how the conical flask go to be so that is the conical flask we have got and what else we have got the pure liquid what are we missing out we are missing out the condenser part right so just try to draw the condenser along with me the condenser has got an inlet and an outlet so that is the inlet and that is the outlet here now what does the procedure see here also what we are missing out again is a thermometer a thermometer is also kept over here along with a fractional eating column we have got I'm just making because there's not enough space so I'm just making the thermometer like that so that is a thermometer fine that is the water condenser so always and always mark the things so we have got a mixture of compounds over here mixture of compounds and that – let's just say a and B the difference between the boiling points in the mixture of compounds here in the case of fractional distillation is approximately n – 30 gallons not more than that so here the boiling points are closer so that is boiling point difference between the two that means the boiling points are boiling points are closer to each other fine so that is the entire technique over here what do we do let us just discuss that I hope everybody has drawn it out now we have got a round bottom flask in round bottom flask we take up the mixture of the compounds that we need to boil up that we need to separate what we are doing is the purification technique we are separating out the compounds with purity so we obtain pure compounds over here in this technique as well if any kind of impurities is present that will remain as it is in the RB flask so that is what it is so we take up a mixture here not in the case of simple distillation in simple distillation we had taken up the boiling points which are the boiling point difference which is quite large because we need to separate it out the liquids one by one we do not have any kind of source other than that over here I have got a source what kind of a source we have we have got a fractional aiding column reaction relating all oh yeah and this column what it does is whenever the liquid gets heated up like that it moves into this fractional ating column it travels so long that the temperature keeps on rising in the Army flask so what happens is first of all if I just assume that the boiling point of a is greater than boiling point of B right so which will boil off first the one having the lower boiling point so this one so it will boil off first the B will be traveling and traveling in the fractionating column slowly and slowly the procedure is very slow so it just travels and travels till the time what happens is the temperature here rises so much that a starts boiling off and when the air starts boiling off the B has almost reached at the top so B has got time to travel up and then gets condensed before mixing with the vapors of a right so we are actually increasing the traveling time we are actually increasing the surface area so here the surface area is increased the traveling time is increased and when it reaches the top when the B reaches the top it gets enough temperature it gets enough time for the a to boil off finally the B condenses off first the B condenses off first and then gets collected over here and again what happens then a will start boiling off after some time so it will boil off and then gets collected so that is how the different liquids get collected and since the liquids are actually having a very very less difference of temperatures of boiling points so we cannot use a simple distillation method because that would gave us both the mixtures of pure liquids so we don't want that we want a separate one so here that is how the separation technique is and not only these type of columns we have got different kind of columns so a column would be like this as well so we have got different kinds of formations like this that is how one column could be we need to just provide the enough surface area we need to just provide the enough timing to travel so that is how our main motive is in order to separate so that is how the different kind of columns look like there are hundreds and hundreds of columns available in the market which has got a different kind of structures different kind of shapes present then just in order to have a different kind of attainments different kinds of organic compounds attained so depending upon the criteria depending upon the type of organic compound we want to obtain we use different kind of columns we can choose different kind of columns also there are such columns which are having bulbs like that so that is also column so these are the bulbs these are the different shapes of the columns and I hope everybody has got the procedure what we have done so we have just boiled off and till the time the B rises the B gets collected over here it first condenses then a will come up that is how the procedure is I hope everybody is clear with the fact we are through with the fractional distillation as well what is and where is this technique used so fractional distillation most commonly is used whenever we are separating remember the procedure of pyrolysis you must have done this in lower classes pyrolysis and the breakdown of the crude oil in two different kinds of oils that means kerosene paraffin wax and patrol whatever it is so there are so many kinds of gradations in crude oil we can obtain so many kinds of oils from the crude oil the procedure involves a fractional aiding column a fractionating column just as we have done this here but a quite a bigger one something like this you can say so this column is so big that is it has got so many inlets over here so depending upon the boiling points the liquids will boil off and then condense from different outlets and the different outlets actually attain or obtain a different kind of oil stem so that is used it is so let me just try it over here fractional distillation used in separation of different products products from crude oil you must have recalled the concept that is the cracking of hydrocarbons so yes so we have done this already so I hope everybody is clear with the idea now let's move on to the next one what is the next one is the reduced pressure distillation what is reduced pressure distillation this particular distillation is actually used whenever we are having so much of high boiling point for a compound that we cannot just heat the RV and then obtain it so in order to that what we do is we reduce the pressure of the liquid on the surface of the liquid and it boils off that means we are in turn reducing the boiling point so here is the technique the distillation technique most suited for separating glycerol from spent lye in the soap industry is so first of all let us just analyze what the question says so they are asking about some kind of distillation technique and what we have done so far is different kind of distillation techniques which are given over here so suited for separating now we need to separate glycerol from the spent light what is this particular thing glycerol from the spent lies basically nothing but the saponification reaction and the spent lye is basically what this pent lye is the alkaline glycerol what is this alkaline glycerol when the fat is converted into saponifies into what is a quantification into the glycerol along with the soap naturally so what is left in the mixture is glycerol along with the soap that is alkaline mixture of both that is known as the spent line so we need to separate it out and we need to take out the glycerol as a whole so for that purpose if I go for the simple distillation so that would be a cumbersome process because simple distillation would be requiring lesser temperatures but if we go on to the boiling point of glycerol so I would like to tell you over here the boiling point of glycerol is approximately 290 degree Celsius right which is quite high so simple distillation will be unable to achieve this much of temperature easily if I go by fractional distillation again it would be a very very improper method steam distillation if I go so steam distillation also it must be having some immiscibility with the steam with in with the water and that is not possible over here because glycerol is soluble in water right so here all of these three methods will be wrong but distillation under reduced pressure which will actually reduce the boiling point of the glycerol and now glycerol can easily boil off easily separated so that is what the answer over here is distillation under the reduced pressure so we need to reduce the pressure of the entire reaction mixture reducing the boiling point of the glycerol separating it out clear so answer is D over here let's move on to the next question very next question what does it say a miscible mixture of benzene and chloroform can be separated by so I have given a lot a lot many techniques here so let us just analyze first what benzene is benzene is a non-polar compound right whereas chloroform will be polar but they are saying over here is a miscible mixture they have taken that means they have taken both of them in such a quantity that they are miscible with each other so there's no point of sublimation because sublimation is solid to vapor conversion right so here both of the things are in liquid state chromatography again we are not sure about what kind of adsorption will be there on the stationary phase crystallization what is crystallization we need to first dissolve it into some solvent but these are itself liquids so how can that be possible and now comes up the distillation and also I would like to tell you a point over here in crystallization is if I've got a liquid only and then I boil off then I heat it out with some kind of solvent what will happen if I then try to cool it down again I will be getting the liquid and not the crystals so the condition for crystallization is we must be having what a boiling a melting point right melting point a higher then the room temperature right so that is how we can obtain some crystals at room temperature for that substance so this crystallization is also not applicable because here both of them are liquids benzene is a liquid and chloroform is also a liquid at room temperature now comes up the distillation so if I look at the boiling points the boiling points of benzene so it will be around 80 degrees Celsius whereas for the chloroform it's around 60 degree Celsius so there is a difference of 20 degree Celsius boiling points so right we can apply we can take out the method of distillation for the separation and to be very precise I can also use the method for fractional distillation because the two boiling points are closely related right so I can have to be very precise steam distillation sorry non the steam but the fractional distillation over here and thereby the correct answer is d i hope everybody has got it which of the following compounds gives blood red coloration when it's lust signs extract is treated with alkali and ferric chloride right so again the question for assigns extract a very very famous la signs extract an organic compound and organic solution that is used to detect the various elements present in the organic compound right so they are asking about when are we getting the blood red coloration when the lesan extract is treated with alkaline ferric chloride so basically for this particular question you need to have a proper knowledge about what all reactions are happening so I've got the le right I need to react it with alkali and then ferric chloride so how do we get the blood-red coloration that is the question over here so the blood red coloration how does it observe how it's get observed is the Le should be in the form of first of all any Sen right sodium thiocyanate so that is the Le which is need to be there and when this le reacts with Fe 3 plus ions it will give what it will give the blood red coloration now what is the compound which is formed so that is the compound which is formed which actually is responsible for the blood red coloration into the solution so that is blood red coloration right so what we need over here is in this particular reaction in this particular reaction we need to form Sen that is thiocyanate and for this SCN we need to have s c and n all the three elements present in the reaction side right so out of these three out of these four options what is the answer so first of all if I consider the IOU urea you need to have a proper information about what is the structure of all of these compounds how you do looks like this next is diphenyl sulfide so I hope everybody knows what dye self diphenyl sulfide if if not you can just very easily form the formula so that is the structural formula for it diphenyl hydrazine if you just look here very carefully in diphenyl hydrazine as well you will not found it you will not find any sulfur present over here right so there is no sulfur present right in bends amide as well no sulfur over here sulfur is present but nitrogen is not present so no nitrogen and it is the only a option in which nitrogen carbon as well as the sulfur is present that is what we need in the particular reaction getting the blood red coloration so we need sulfur carbon and nitrogen whenever a question pops up about what all compounds will give the blood red coloration you need to just see which compound contains all the three that is sulfur carbon and nitrogen is the important thing over here I hope everybody now remembers it is the correct option now let's move on to the next question so what does the next question say okay now it's the type of multiple type question multiple choice sodium fusion extract obtained from aniline what is sodium fusion extract that is lel assigns extract obtained from the aniline on treatment with iron sulfate and sulfuric acid in the presence of air gives Prussian blue crucian blue color again it will remind you of what the test for the nitrogen right that is the detection test for nitrogen where we get the Prussian blue color hence the blue color is due to the formation of you need to have a proper knowledge about what all reaction is going on but as you can see it's a multiple choice question so we need to be very careful while choosing our choices right so first of all let us just have the reaction related to it so the reaction is if I get three and negative that is from the le nez and right what was the Le initially taken NaCl it reacts with Fe plus 2 ions right that is coming from the ferrous sulfate and what we get is this is hexa sign of ferret so this is what we get we are not complete yet next is when due to the presence of this sulfuric acid it converts most of the FE 2 plus ions into fe 3 plus so those also react with the compound which is fault for negative plus what Fe plus three ions giving the compound that is Fe for fe CN six whole thrice so that is what we are getting ferry Ferro cyanide right ferry stands for the ferric over here Ferro stands for the ferrous over here right and we need to look for this particular option so if you look for this particular option I will be getting only one as my answer that is a if you go by the other options Fe plus 3 let us just check because this is a multiple choice question so Fe three-plus over here if this is Fe three-plus right that means this will be ferrous because this is to the counter ion is two by the cross multiplication method I have found out that this plus two this cannot be the case again by the cross multiplication plus two again cannot be the case and by cross multiplication yes this is plus three but this would be three minus which is not at all formed in the reaction mixture so this particular multiple this question appeared in the multiple choice question but that is just to confuse you because some of the students might think that there will be multiple answers going on over here so they may mark one or maybe more than one options that would make your answer completely incorrect so you need to be very careful by choosing the options this has got only one answer right right so that is a we have got it already so I hope everybody is clear with it so it is not necessary that each and every multiple choice question will be having multiple answers so you need to be very careful next question says okay now it's the comprehension type question what is the passage over here during the detection of elements by the science test again the sinus tract question the covalent compounds are converted into ionic compounds by fusion with metallic sodium right they've told us the process of what all process is happening in the law science test right the nitrogen sulfur and the halogens present in the organic compound these are the detection of elements via the science test right so in the organic compound are converted into cyanide sulfide and halides respectively we all know that which are then detected by their usual tests so that is they have given just an information about how the license extractors fall and what is the use of this law science extract I hope everybody gets that now let us just check the questions based on it an organic compound containing n c o as an extra elements is fused with the sodium metal and then extracted with water the species which is not present in the solution of the extract so I've got my trojan let me just rub that I've got my Trojan I'm good sulfur I've got oxygen fused it with na what all do we get NaCl and a 2 s right we all know what all are the formations and for oxygen there is no such kind of an interaction with the sodium so then these are extracted with the water I've got an alkali as well right the species which is not present in the solution extract now the solution extract we have formed so these are the species which can be formed over here I can have CN right I can have CN s right I can have sulfide but nitrate cannot get formed over here so that is there is no such possibility of formation of nitrate this can be possible if the sulphur gets hindered with the nitrogen so in that case we get n AC n s right in that case we get this otherwise we can just get the sulphide right and there is no chance of formation of nitrate a nitrate here right so that is the option right so I hope everybody has got it answer number C is the correct one yeah we have ruled out all the other possibilities

Hess's Law – Chemistry Tutorial



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This chemistry tutorial covers how to solve for the enthalpy of reaction for an given reaction by using Hess’s Law and the delta H values for other known chemical reactions. This tutorial involves several examples demonstrating the use of Hess’s Law, which allows for the calculation of an unknown enthalpy of reaction from other reactions due to the fact that enthalpy is a state function.

Redox Reactions: Crash Course Chemistry #10



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All the magic that we know is in the transfer of electrons. Reduction (gaining electrons) and oxidation (the loss of electrons) combine to form Redox chemistry, which contains the majority of chemical reactions. As electrons jump from atom to atom, they carry energy with them, and that transfer of energy is what makes all life on earth possible.

**Special Thanks to Matt Young at the University of Montana (Geosciences Department, Environmental Biogeochemistry Lab) who helped with the chemical demonstrations.**

Oxidation 1:42
Reduction 1:03
Oxidation Numbers 3:29
Redox Reactions 5:59
Oxidation Reactions 6:28
Balancing Oxidation Reactions 7:18

Also thank you to the following chemistry teachers for assistance:
James Sarbinoff
Rachel Wentz
Edi González
Lucas Moore
Chris Conley
Addie Clark
Julia Rosinski

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يُعد الإلكترون بالنسبة للكيمياء
كالمال بالنسبة للرأسمالية. يتمحور الأمر حول من يملكه ومن يريده
وما هو مستعد لفعله للحصول عليه. إن الإلكترونات هي ما يُمكّن الذرات
من الترابط مع بعضها لتشكيل جزئيات، وعندما يحدث ذلك،
يمكن أن يتم تبادل قدر هائل من الطاقة خلال العملية. ولكن لا تتضمن
جميع التفاعلات الكيميائية تبادل إلكترونات فقد تتذكرون أن التفاعلات الحمضية القاعدية
تتضمن تبادل hgبروتونات، لكن لأن الإلكترونات هي العملة المتداولة
في عالم الكيمياء فإن أهم التفاعلات التي تحدث على كوكب الأرض
تتضمن نقل إلكترون واحد أو أكثر من ذرة إلى أخرى. تُسمى هذه تفاعلات الأكسدة
والاختزال أو Redox بالإنجليزية، وهي كلمة مشتقة من كلمتي reduction
وهو الاختزال و oxidation وهو الأكسدة. ما قصة هاتين الكلمتين؟
تعرفون معنى الاختزال، إنه تقليل شيء ما، وربما تتعلق الأكسدة بالأكسجين بعض الشيء…
حسنًا، أحيانًا لكن ليس دائمًا. هاتان كلمتان غير مناسبتان على الإطلاق لما يحدث فعلاً في تفاعلات الأكسدة والاختزال،
لكننا عالقين معهما. الاختزال هو عندما تكسب المادة إلكترونات.
أجل، تكسبها، وهذا عكس معنى كلمة اختزال. هذا عظيم! وصحيح أنني أود في بعض الأحيان
أن ألكم الأشخاص الذين أطلقوا أسماء غير دقيقة على هذه الأشياء،
لكنهم لم يعرفوا الحقيقة وكلهم أموات الآن لذا لا يمكننا فعل شيء حيال هذا. كان الكيميائيون البدائيون يصنعون معادن خالصة
من خلال تسخين أو صهر المواد الخام. ولاحظوا خلال عملية الصهر
أن هذه المواد تصبح أخف وزنًا، لذا لم يكن أمرًا جنونيًا فعلاً أنهم قرروا
أن يقولوا عن هذه المواد بأنها كانت تُختزل. اكتشف صديقنا الفرنسي القديم أنطوان لافوازييه
أن هذا يحدث لأن غاز الأكسجين كان يترك المركب
ما يجعله أخف وزنًا. لكن ما لم يعلمه هو الكيمياء الحقيقية المعنية بالأمر.
إن الأكسجين هو المؤكسد المثالي، فهو يسحب إلكترونًا
من جزي واحد ليجعل نفسه مستقرًا، لكن إن سخنتموه إلى حرارة كافية، يصبح نشيطًا. نفهم اليوم أن الأكسدة والاختزال يتعلقان بنقل
الإلكترونات، لذا يتوقع المرء أن نعيد تسميتهما وقد حاول بعض الكيميائيين فعل ذلك، وأطلقوا
أسماءً عليها مثل الألكترنة وإزالة الألكترنة، لكن ما إن تصبح مجموعة من المصطلحات
مُقررة وتُستخدم لفترة من الزمن تصبح إزالتها صعبة جدًا. لذا نحن عالقون معها.
ولأحفظ وأفرّق بين هذين الإسمين غير المنطقيين أعتمد على كلمة "أخاك"،
وهي أن الأكسدة خسارة الإلكترونات والاختزال هو كسب الإلكترونات. يجب علينا
أن نعرف هذه الأشياء فحسب لأنها في كل مكان. عندما تحول خلاياكم
السكر إلى طاقة كي تتحركوا وتتنفسوا وتفكروا هذا تفاعل أكسدة واختزال. حين تحول النباتات
أشعة الشمس إلى طعام عبر التركيب الضوئي، هذا تفاعل أكسدة واختزال. البطارية التي تشغل
الحواسيب والنار، إنهما تفاعلا أكسدة واختزال. بما أن تبادل الإلكترونات هو الموضوع الرئيسي،
حين تدرسون تفاعلات الأكسدة والاختزال، فإن تتبع الإلكترونات
هو أمر مهم وضروري وأساسي جدًا. تخيلوها كعملات، ففي أي صفقة، سيكسبها شخص ما وسيخسرها شخص آخر.
ومن أجل أن تبقوا متحكمين في الأمور يجب أن تراقبوا من يكسب ومن يخسر. لكن الذرات مولعة بمشاركة الإلكترونات
وتشكل روابط تساهمية لذا يكون تتبع أماكنها وأين ستذهب
ليس بأمر سهل في بعض الأحيان. أحب تخيل أن كل مركب تساهمي يشبه زواجًا.
لكنه سيكون زواجًا غريبًا لأنه قد يكون فيه ستة أشخاص،
وقد يكون الشخص نفسه موجودًا عدة مرات، ولا يوجد فيه التزام ولا عواطف.
لا تفكروا فيه كثيرًا. ومثل الزواج، حيث تتم مشاركة المال فيه،
تتشارك المركبات التساهمية بالإلكترونات. والحيلة هي معرفة من سيحصل على المال عند نكث
العهود. لذا استحدثنا نظامًا مفيدًا جديدًا وهو تعيين جميع الإلكترونات للذرات
التي تتشاركها في تلك اللحظة. يُدعى عدد الإلكترونات الذي نعينه
بحالة الأكسدة أو بعدد الأكسدة للذرة. ومع أننا على دراية تامة
بالروابط التساهمية وتشارك الإلكترونات، إلا أنه من الأسهل تتبع العمليات
إن تخيلنا أن الذرات تتقاسم إلكتروناتها، وكأنها في رابطة أيونية أو رابطة غير تشاركية. إذن، عدد الأكسدة للذرة هو ما ستكون شحنتها لو كانت تملك جميع الإلكترونات بشكل حصري حقًا. إذن، لفهم حالات الأكسدة أو أعداد الأكسدة هذه لدينا قواعد بسيطة لبعض الذرات.
أولاً، عدد الأكسدة لأي عنصر لوحده، سواء كان أحادي الذرة أو ثنائي الذرة
أو متعدد الذرات مثل ذرة الكالسيوم أو جزي هيدروجين أو حتى جزيء الكبريت الثماني
الأكبر حجمًا، يكون عدد الأكسدة صفرًا. لا تملك الذرات شحنة بطبيعتها،
فإن كانت تملك شحنة ستكون أيونات، وإن كانت تتشارك مع نفسها، تتشارك بالتساوي.
وثانيًا، بالنسبة لأيون أحادي الذرة، وهو ذرة مشحونة ببساطة،
يكون عدد الأكسدة هو حجم أو رقم شحنته. إذن الحديد في أيون Fe2 الموجب
يمتلك حالة أكسدة تساوي موجب اثنين، وتساوي سالب 1 لأيون الكلوريد. ثالثًا، الأكسجين
المستفحل في كيمياء تفاعلات الأكسدة والاختزال يمتلك دائمًا تقريبًا حالة أكسدة تعادل
سالب اثنين، إلا إن كان في جزيء بيروكسيد مثل بيروكسيد الهيدروجين.
رابعًا، حالة الهيدروجين تعادل موجب واحد. وخامسًا، حالة الفلور تعادل سالب واحد
مثل جميع الهالوجينات الأخرى في معظم الأحيان، إلا إن كانت مرتبطة بالفلور أو الأكسجين،
لأن الفلور والأكسجين سيئان جدًا لدرجة أنه يمكنهما أن يجعلا عدد أكسدة
أي عنصر موجبًا إن كنتم تعلمون ما أقصده. وهذه هي القوانين، هذا كل ما يجب أن تعرفوه.
سيكون مجموع جميع أعداد الأكسدة لجميع الذرات في مركب متعادل الشحنة صفرًا.
مثل الماء الذي يحتوي على ذرة أكسجين لديها حالة أكسدة تساوي سالبة اثنين وذرتي
هيدروجين حالة كل منهما تساوي موجب واحد وهكذا، يمتلك المركب المتعادل الشحنة عدد أكسدة يساوي
صفرًا. لكن أيون متعدد الذرات من الناحية الأخرى يجب أن يمتلك حالة أكسدة تماثل
شحنته، لذا SO42 السالب، وهو أيون الكبريت، لديه أربعة ذرات أكسجين
تساوي سالب ثمانية، لكن لا توجد قاعدة للكبريت لذا أعتقد أنه علينا أن نستسلم ونرحل.
من يكترث لهذا الآن؟ كلا! نستخدم علم جبر بسيط جدًا
لأنه يجب أن نملك في النهاية عدد أكسدة يساوي سالب اثنين للمركب بأكمله،
ونحن نعلم أن الكبريت في هذا المركب المعين يمتلك حالة أكسدة تساوي موجب ستة. لكن
حالة أكسدة الكبريت لا تساوي موجب ستة دائمًا ولهذا لا توجد قاعدة للكبريت
أو للعديد من العناصر الأخرى في هذا الشأن لأن حالات الأكسدة لمعظم العناصر
تتغير بحسب العناصر المرتبطة معها. والآن بإمكاننا تطبيق
المنطق نفسه لاكتشاف ما يحدث عند تفاعل هذه المركبات في تفاعلات الأكسدة
والاختزال. محاكم طلاق الإلكترونات الجزيئية حيث تنتقل من طرف لآخر ويتم التفاوض عليها
ومقايضتها حيث يأخذ بعض المشاركين أرباحًا كبيرة بينما يخسر آخرون كل شيء تقريبًا.
هذه هي الحياة! لنبدأ بمثال بسيط: تفاعل كيميائي
قام برأيي بإنقاذ أرواح أكثر من أي تفاعل آخر في تاريخ الكيمياء، صُنع من قبل مجرم حرب
لتفجير الناس خلال الحرب العالمية الأولى، وهو طريقة هابر. تزيل طريقة هابر
عنصر النتروجين شديد الاستقرار من الهواء وتدمجه مع الهيدروجين لتكوين NH3
وهو أمونيا، ليتم استخدامه في القنابل وفي السماد أيضًا،
ما يزيد من قدرة التحمل للأرض بمقدار مليارات. يوجد النتروجين في الهواء
كنتروجين عنصري ثنائي الذرة، والهيدروجين عنصري ثنائي الذرة مثله،
لذا نعلم منذ البداية أن جميع الذرات تملك حالة أكسدة تعادل صفرًا.
نتاج التفاعل هو الأمونيا، وهو مركب متعادل الشحنة يمتلك ذرة نتروجين
وثلاث ذرات هيدروجين تملك كل منها حال أكسدة تعادل موجب واحد. تذكروا القواعد، لذا يجب أن
يمتلك النتروجين حالة أكسدة تعادل سالب ثلاثة. وبالتالي اكتسب النتروجين إلكترونات،
فانخفضت حالة أكسدته ولذا اتم اختزاله.
عندما نتحدث عما تفعله حالات الأكسدة، تكون كلمة "اختزال" منطقية. فقد الهيدروجين
إلكترونات فارتفعت حالة أكسدته وتمت أكسدته. هذه معادلة توازن بسيطة جدًا، لكن يمكن
أن تكون معادلات تفاعلات الأكسدة والاختزال عويصة جدًا في بعض الأحيان
بسبب عدد الذرات الفردية المشتركة فيها، لذا علينا أن نوازنها
في تفاعلات نصفية في الغالب. مع أنه ليس علينا أن نقوم بالتفاعلات النصفية
لأنها معادلة بسيطة جدًا، سنقوم بها على أية حال
لأنها مثال بسيط لنبدأ به. لذا نبدأ باختزال النتروجين. لدينا N2 حالة أكسدته تساوي صفرًا
ويصبح NH3 حالة أكسدته سالب ثلاثة. أولاً نعادل عدد ذرات النتروجين،
ثم نضيف إليها عدد الإلكترونات التي يجب أن تكون موجودة ليكون عدد الإلكترونات
نفسه موجودًا في كل جهة من المعادلة. قوموا بالشيء نفسه لنصف تفاعل الأكسدة
ثم اجمعوهما لتحصلوا على التفاعل بأكمله حيث تلغي الإلكترونات بعضها.
والآن تتساءلون إن كانت تلك خطوة غير ضرورية لكن اسمحوا لي أن أعرض عليكم
تفاعلاً أكثر تعقيدًا سيثبت لكم كم يمكن أن يكون ذلك مهمًا.
يوجد ديامين الفضة في هذه القارورة. سنستخدم تفاعلات أكسدة واختزال كيميائية لإخراج
عنصر الفضة منها بشكل لطيف ونظيف ولامع، ولن تكون بطريقة هابر بسيطة على الإطلاق.
سيتفاعل ديامين الفضة مع ألدهيد عضوي، أو أي ألدهيد في الحقيقة. الجانب الأساسي من الألدهيد هو CHO. والـ R
في الكيمياء العضوية هي رمز لمجموعة ذرات عضوية ولا توجد أهمية لهذه الذرات في هذا التفاعل. يتفاعل ديامين الفضة مع الألدهيد والهيدروكسيد ما ينتج حمض الكربوكسيل والأمونيا والماء.
أولاً، لنُعين بعض حالات الأكسدة. الفضة موجودة في مركب
يحتوي أيضًا على ذرتي أمونيا متعادلتي الشحنة ولن تتفاعلا طوال التفاعل،
لذا يمكننا أن نعاملهما وكأنهما نوع واحد وحالة أكسدته تساوي صفرًا.
بما أن شحنة ديامين الفضة موجب واحد ولا تؤثر الأمونيا على ذلك،
يجب أن تكون حالة أكسدة الفضة موجب واحد أيضًا. يمتلك الألدهيد ذرة هيدروجين شحنتها موجب واحد
وذرة أكسجين شحنتها سالب اثنين لكنه مركب متعادل الشحنة لذا لا بد
أن تكون شحنة الكربون موجب واحد أيضًا. شحنة أيون الهيدروكسيد بسيطة:
سالب اثنين للأكسجين وموجب واحد للهيدروجين وشحنته الإجمالية سالب واحد في حالة الأكسدة
هذه. في جانب المتفاعل، أصبحت الفضة ذرة الآن لذا إن حالة أكسدتها تساوي صفرًا. يحتوي حمض
الكربوكسيل على ذرتي أكسجين وذرة هيدروجين لذا حالة أكسدة الكربون الآن تعادل موجب ثلاثة.
تبقى شحنة NH3 صفرًا ولم يغير أكسجين وهيدروجين الماء
حالتا أكسدتهما أيضًا. لذا انخفضت حالة أكسدة الفضة،
أو تم اختزالها، من موجب واحد إلى صفر بينما تمت أكسدة الكربون من موجب واحد
إلى موجب ثلاثة. حان وقت نصف التفاعل. تم اختزال الفضة واكتسبت إلكترونًا واحدًا
فشكّلت عنصر فضة وأمونيا من ديامين الفضة. تمت أكسدة الألدهيد
وشكّل حمض كربوكسيل ويحتاج إلى إلكترونين. نعلم بمساعدة هذه الإلكترونات
أنه على أقل تقدير يجب علينا أن نضاعف كامل نصف اختزال المعادلة
من أجل أن نحصل على عدد الإلكترونات الصحيح في كلا الجهتين.
نفعل ذلك و… يا إلهي، هذا أمر جميل! ثم ندمجهما معًا لنحصل على معادلة
تفاعل أكسدة واختزال متوازنة تمامًا. والآن شاهدوني
وأنا آخذ هذه الإلكترونات وأحولها إلى مال. وها هي أمامكم أيها الناس،
هذه فضة خالصة تكسو القنينة من الداخل. شكرًا على مشاهدة هذه الحلقة. إن كنتم منتبهين، تعلمتم أن أي تفاعل
تنتقل فيه الإلكترونات من ذرة إلى أخرى هو تفاعل أكسدة واختزال،
وأن الأكسدة هو خسارة الإلكترونات وأن الاختزال هو كسب الإلكترونات،
وتعلمتم أنه يتم تعيين أعداد الأكسدة للذرات المشاركة في التفاعلات من أجل أن تقوم بتتبع
ما تنوي إلكتروناتها على فعله. تعلمتم بعض الحيل البسيطة
لتساعدكم على معرفة ما هي حالة أكسدة ذرة ما وتدربتم قليلاً
على معرفة كيفية تعيين حالات الأكسدة وموازنة تفاعلات الأكسدة من خلال مثالين، أحدهما سهل جدًا والآخر أقل سهولة. كتبت أنا وكيم كريغر هذه الحلقة،
ومحرر النص هو بلايك دي باستينو. الدكتور هايكو لاغنر هو مستشارنا الكيميائي،
وقامت مجموعة من معلمي الكيمياء بتقديم المشورة لهذه الحلقة وبتحريرها،
لذا شكرًا جزيلاً لهم. هذه الحلقة من تصوير
ومونتاج وإخراج نيكولاس جنكينز، مصمم الصوت ومستشار النص هو مايكل أراندا،
وفريق الرسومات هم Thought Café.

How do some animals glow? — Speaking of Chemistry



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What’s the difference between fluorescence and bioluminescence? We illuminate the biochemical distinctions. ↓↓More info and references below↓↓ Special …

Converting Grams to Moles Using Molar Mass | How to Pass Chemistry



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Let’s figure out what the difference between molar mass and atomic mass is and learn to use molar mass as a conversion factor and stop guessing on how to …

Balancing Chemical Equations With Fractions | How to Pass Chemistry



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Oh no, not fractions!! Don’t worry I got you covered when it comes to balancing chemical equations using fractions, this video makes it super easy! If only life …

Learn Functional Groups FAST (Organic Chemistry)



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Check out the new and improved version here: Learn the basics of functional groups for your Organic Chemistry class in under 5 …

Entropy: Embrace the Chaos! Crash Course Chemistry #20



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Life is chaos and the universe tends toward disorder. But why? If you think about it, there are only a few ways for things to be arranged in an organized manner, …

How to Use a Mole to Mole Ratio | How to Pass Chemistry



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Soon you will be saying, “Holy guacamole I understand how to use mole to mole ratios!” In this video, you will learn when and how to use mole to mole ratios …

Scientific Notation and Standard Form Explained with Practice Problems | How to Pass Chemistry



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Scientific notation and standard form are easily explained in this video! Learn how to go from standard form to scientific notation and practice a few problems to guarantee you get the concept.

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Practice problems with step by step answers:

TIMESTAMPS
0:33 Standard Form vs. Scientific Notation
0:49 Scientific Notation Setup
1:22 Converting small numbers to scientific notation
2:29 Converting from scientific notation to standard form
3:10 Converting large numbers to scientific notation
6:24 Practice Problems

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In this video you are going to learn how
to write numbers in scientific notation and in standard form. Alright let's do
this! hello-hello Melissa Maribel here and I help
students like you understand what you just learned in class so you stress less
and you graduate faster. Hit that subscribe button and we'll pass
chemistry together. On to scientific notation. Scientific notation is just an
easier way to write really small or really large numbers. You will have two
different forms, standard form is just the expanded form of that number or the
number itself and scientific notation is just the condensed form of that same
number. The proper set up for scientific notation, you will always have one
non-zero number followed by a decimal then after that decimal you will have
one or more numbers. Doesn't matter if it's 0 or not and that would have been
times 10 to the some sort of exponent. So you'll see for example we have 2.30×10 to the 4th. That is an example of your proper scientific notation. If
you wanted to then write a really really small number into scientific notation,
remember that all small numbers will have negative exponents when you put
them in scientific notation. So all numbers less than 1 have negative
exponents. Let's try one. Write 0.0007211 in scientific notation. This is your clue
this is a very small number or it's less than 1. So it will have a negative
exponent. What we're going do, take that decimal place and we're going to
move it all the way to that 7 because that is your first non-zero number. So
moving this over 1, 2, 3, & 4 putting our decimal place there, we know
that we will have a negative 4 as our exponent because that's how many places
we move to get to that first nonzero number.
So our proper scientific notation is then 7.211×10 to the negative
4th. When we're writing numbers that are already in scientific notation and going
back to standard form that exponent tells you whether or not
to move to the right or to the left. So if it's negative you're actually going
to move to the left and if it's positive you're gonna move to the right. 8.72×10 to -3rd we're gonna write that in standard form. You'll see that we have a -3 as our exponent so a -3 recall that tells us it's going to be a
number that is less than one so we're going to move the decimal place to the
left three. So I'm going to move this over one two and three and my decimal
place is here. I'm going to place a zero wherever I had any missing spaces and
our final answer is 0.00872. When you're converting
really large numbers into scientific notation large numbers have positive
exponents. All numbers larger than one have positive exponents. For example
let's write this ridiculously large number into scientific notation. So
clearly this is larger than 1 so we know it will have a positive exponent.
Your decimal place is always after the 0 or always after that last value
since there wasn't initially a decimal place and we're going to move this all
the way over to this 9 because that's our first non-zero number. So I'm going
to just count one, two, three, four, five, six and seven. So our setup will be 9.0 and then following with all of the numbers that we had before times
10 to the positive 7. Seven because we move that decimal place over seven
times. Let's write 1.489×10 to the 5th in standard form. Remember standard form now, is just the
expanded form of this number. That 5 tells us it's a very large number. So
from that decimal place we're going to actually move over to the right five
times. One, two, three, four, five, placing that decimal place here which
really it's gone. This would have been zero and zero. The reason I say that that
decimal place is gone is because it's now a really large number and there's no
need to put a decimal place since there is no numbers following. So this would be
our correct number in standard form. Sometimes you have numbers that look
like they're in scientific notation but they actually have two numbers in front
of that decimal place and we know that that's not correct. So how do you change
them back? If you're trying to move that decimal place to the left, you will add
how many decimal places you're moving to that exponent. Now if you're going the
other way if you're going to the right, you're actually going to subtract. I know
it's always the opposite of what you're thinking or what you're used to, but
let's try some. Though this number looks like it's in scientific notation, it's
not because remember we have to have one non-zero number in front of that decimal
place but instead we have two. So we have to move this decimal place over one,
whenever you move over one to the left you will add 1 to that exponent. So
instead we have 1.2409×10^-5 because we added a 1 to that exponent. Now we're trying to move this decimal
place over one. When we move that over once to the right we will subtract this
exponent by one making it a negative four so when we move over to the left
you add and when we move to the right we subtract. Now it's just you me and these
practice problems. For practice problems with
step-by-step answers, check the description box. Also let me know if you
want to see more "How to pass Chemistry" videos by liking and subscribing. And
leave a comment below letting me know why you want to pass chemistry and I'll
see you next week.

Introduction to Biology: What is Life?



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After we learn chemistry and biochemistry, we are ready for biology! In this course we extend our understanding of molecules to encompass an entire cell and everything inside it. This is a huge step in complexity, and we will even talk about how the first cells may have come about. First just a little introduction to whet your whistle!

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أهلا، أنا بروفيسور ديف. أريد أن أحدثكم عن علم الأحياء. هل نظرت يوما إلى المرآة وتساءلت ما هو بالضبط الشيء الذي ينظر إليك بالمقابل ؟ بالطبع هو أنت. لكن من أنت ؟ إذا كنت قادرا على فهم الكلمات التي أقولها. على الغالب أنت كائن بشري. لكن مهما كنت. أنت من المؤكد مخلوق حي ، بما أنك تستوفي جميع المعايير الموجودة لتعريف الحياة وما تفعل. أنت تتحرك، تستخدم طاقة ، تستجيب للمثيرات، و تتكاثر أو ستفعل يوما ما ، حتى لا تخيب ظن أبويك. إذن مما تتكون المخلوقات الحية بالضبط؟ هناك العديد من الطرق للإجابة على هذا السؤال، وذلك يعتمد إلى أي مدى تريد التعمق في الإجابة. أصغر الأشياء داخلك هي جسيمات متناهية الصغر تدعى الكواركات والإلكترونات. هذه الجسيمات تتجمع معا لتكون الذرات، التي تكون الجزيئات ، والتي تكون بدورها جزيئات أكبر حتى نصل في النهاية إلى الخلية خلية واحدة هي أصغر شيء يمكن اعتباره حيا، وكل شيء حي -على الأرض على أية حال- فهو مكون من خلايا، سواء كانت خلية واحدة أو العديد من التريليونات من الخلايا من البكتيريا وصولا للكائن البشري. جميعنا مكون من خلايا. لو أردت تعلم المزيد حول الكواركات وبقية الجسيمات، فسترغب بدراسة بعض الفيزياء للذرات والجزيئات ، ستحتاج لدراسة الكيمياء، وعندما يغدو حجم هذه الجزيئات كبيرا جدا ،حينها ستحتاج للكيمياء الحيوية لكن عندما نصل لخلية كاملة، يجب علينا دراسة علم الأحياء، لأن الخلايا مسؤولة عن تكوين الحياة والأحياء هي دراسة الحياة. يمكن أن يكون تدريس الأحياء صعبا، لأنها غالبا أول علم ندرسه في المرحلة الثانوية. مما يعني أننا أحيانا يتحتم علينا تعلم أمور يصعب علينا فهمها لأننا لم نتعلم حتى الآن المواد التي يرجع (يتحلل) إليها علم الأحياء وبالرغم من ذلك ، إذا كنت طالبا شابا في المرحلة الثانوية تدرس الأحياء لأول مرة فقد وصلت للمكان المناسب، ولك الحرية لتبدأ رحلتك العلمية ها هنا إذا كنت أكبر عمرا و تبحث عن معرفة أكثر شمولا ، فهذه الدروس لك أيضا لكن قد يكون من الأفضل أن تعود أولا لبعض دروسي الأخرى لتكون قادرا على تعلم الأشياء التي تٌكون الخلايا، خاصة الذرات والجزيئات، والتي غطيناها في علم الكيمياء والكيمياء العضوية، إضافة إلى الجزيئات الحيوية الأكبر حجما التي تحدثنا عنها في الكيمياء الحيوية، لأن عدم المعرفة في هذه المواضيع ، فإن المبادئ الحيوية يجب حينها أن تؤخذ -بكثير أو قليل- على الإيمان (يقصد : أخذها كمسلمات دون فهم عميق للمبدأ). نسمع بأن الدي ان اي هو الشفرة الوراثية، لكن كيف ذلك؟ للكثيرين، يبدو الأمر كالسحر. لكن إذا كنت حقا تفهم الكيمياء والكيمياء الحيوية، فإن الأحياء ستغدو مفهومة ومنطقية بشكل كبير لهذا السبب كثير من الطلاب يعودون للأحياء في مرحلة لاحقة من حياتهم بعد دراسة بقية العلوم مهما كان مستوى معرفتك أو هدفك من هذه الدروس، لا تردد بالنقر على الكروت في زاوية الشاشة عندما تراهم، لتُنقل لدرس مختلف في سلسة أخرى لي ، والذي سيوضح ما تبحث عنه بتفصيل أكثر. تذكر، كلما تعلمنا أكثر عن الطبيعة ، كلما قل وقل شعورنا بكونها سحرا. الأمر المذهل بشأن الطبيعة هو كونها متعددة المستويات، تحوي الكثير من الوقائع المختلفة لتُكتشف على مختلف مستويات الأحجام كل مرة نكبر حجم الصورة لعدد من القيم الأسية ، فإن عالما جديدا أكثر تعقيدا ينبثق من سابقه، بمثل الطريقة التي تكون فيها تعقيدات الخلية ووظائفها مستحيلة التوقع عن طريق دراسة الجزيئات الصغيرة فقط، و كيف أن سلوكيات الإنسان معقدة جدا مقارنة بعمليات خلوية بحتة يمكن أن نُرجع أسبابها لها فورا. لكن إذا أردنا دراسة العلوم، يجب علينا اختيار مكان للبدء ، وإذا كان هذا المكان لك هو علم الأحياء، فهيا نبدأ. في هذه الدورة سنتعلم أجزاء الخلية ، مجموعة من الكائنات وحيدة الخلية، والطريقة التي تطورت فيها على مدار بلايين السنوات القليلة لتصبح جميع المخلوقات الحية على وجه الأرض اليوم. لكن كيف نشأت الحياة أولا على وجه الأرض؟ هل هذا أمر يستطيع أي شخص معرفته فعلا؟ لنناقش هذا في المقطع القادم شكرا لمشاهدتكم اشتركوا بقناتي لمزيد من الدروس ادعموني على باتريون لأستطيع الاستمرار بصنع محتوى وكالعادة ، لا تترددوا بالتواصل معي عبر الإيميل

Hybrid Orbitals explained – Valence Bond Theory | Crash Chemistry Academy



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This video looks at hybridization of carbon’s valence orbitals in a bond, including single, double, and triple bonds. Explained are orbital overlap, sigma and pi …

Calorimetry Concept, Examples and Thermochemistry | How to Pass Chemistry



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After watching this video you will no longer be in hot water when doing calorimetry questions. This video not only explains how to do calorimetry problems but it …

AQA A-Level Chemistry – Nomenclature



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This (long!) video runs through how to name a range of organic molecules as per the A-Level Chemistry syllabus. EDIT: molecules within the same homologous …

IGCSE CHEMISTRY REVISION [Syllabus 14] Organic Chemistry



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Hi guys. This is a basic video covering IGCSE organic chemistry. I hope the video helps you to understand and reinforce these concepts for your exams !

Biomentors – AIIMS/ NEET 2020 Batch: Chemistry – Some basic concepts of Chemistry lecture – 3



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1. Determination of percentage of elements in compounds 2. Part per million (PPM) For Important Sheets, Online test & Daily Practise Problems – Please …

Chemistry Lesson: Chemical Formulas



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This lesson shows how to interpret the elemental symbols, subscripts, and parentheses in a chemical formula.

How to Find Limiting Reactants | How to Pass Chemistry



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Just because these reactants are limited doesn’t mean your understanding will be! Limiting reactants or limiting reagents are explained in a simple, quick and visually pleasing way to help simplify Chemistry. This video shows step by step examples of limiting reactants and when to convert moles to grams and grams to moles. This will help you ace that stoichiometry section of your exam!

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To fully understand the concept of
limiting reactant let's make a smoothie. Our first ingredient are strawberries. We
have exactly four strawberries. Our second ingredient is a carton of milk
and we have two cartons of milk. Now these are the ingredients or the
reactants and what we're trying to make or produce is a strawberry smoothie. So
our strawberry smoothie will act as our product. Now to make a strawberry
smoothie this recipe calls for one strawberry and one carton of milk. A
limiting reactant is going to be the reactant that is used up the fastest and
it will produce the least amount of product. So let's see which ingredient or
which reactant will be used up the fastest. Remember our limiting reactant is the
reactant that runs out the fastest. So in this case the milk is going to be our
limiting reactant because it ran out the fastest. Now what is left over is our
excess reactant. So the strawberries will be our excess reactant. Then two
strawberry smoothies were produced that is known as your theoretical yield.
Whatever your limiting reactant is able to produce is known as your theoretical
yield. Let's try that example. If 14.32g of N2 reacts with 4.21g of
H2 to produce NH3 what is the limiting reactant? This question provides us with
a balanced equation. Let's move on to step one. Step one, convert grams of each
reactant to grams of product. Since we're going from grams of each reactant our
first reactant is N2 so let's plan this out. For N2 we're gonna go from grams of
N2 to then moles of N2 using our molar mass of N2 and then from moles of N2 go
to moles of NH3. In order to do this remember this is our mole to mole ratio,
let's bring back our balanced equation and then after moles of NH3
we'll get 2g of NH3 which is what we wanted. We want to go from grams of
our reactant to grams of our product and note we will do this for both reactants
N2 and H2. We'll go from N2 to grams of NH3. So
starting with our given amount, the 14.32g of N2 which was given in
the initial question, we'll align the grams of N2 and grams of N2 remember
this is going back to molar mass. 28.02 grams is the molar mass
of N2. So we'll place this across from each other
putting our 1 mole of N2 on top and then what will happen is our grams of N2 and
grams of N2 will cancel. So now that our grams of N2 cancelled out, we are on our
next step which is going from moles of N2 to moles of NH3. So since we're going
from moles of one compound to moles of a completely different compound we have to
use our balanced equation. So where I'm gonna pull these moles or this mole to mole
ratio is from the coefficients or numbers in front of our compounds in our
balanced equation. So we'll align the moles of N2 and moles of N2 across from
each other. Where I got this 1 from was, if there is no number in front of N2 or
no number in front of that compound then assume that there's a 1 in front and
that's exactly what I placed here for our mole to mole ratio. Next I'll go to
moles of NH3 and we have 2 moles of NH3 going back to our balanced equation
that's where I pulled that number from we have 2 moles of NH 3 in our
balanced equation. Now our moles of N2 and moles of N2 will then cancel. Now that our moles of N2 have cancelled we're at moles of NH3, so we're at this part.
Our last step here now is to go from moles of NH3 to grams of NH3.
Whenever we're going from moles to grams we'll use the molar mass and in this
case we'll use the molar mass of NH3. So we'll align the moles of NH3 and moles
of NH3 across from each other and then we'll put our molar mass or grams on top
for NH3. Now what will happen is the moles of NH3 Will cancel and we will be
left with grams of NH3 which is what we wanted to get. We started with grams of
N2 and we worked our way to grams of NH3. So this was our grams of our reactant to
grams of our product. After we multiply straight across
and then divide by 28.02 we'lll get 17.42 grams of NH3. We went from grams of N2 to
grams of NH3, we have to do the same exact process but this time for H2. So
once again we'll go from grams of our reactant to grams of our product and how
we'll do this is starting with our grams of H2 we'll convert this to moles of H2
using our molar mass of H2 then from moles of H2 to moles of NH3 using a mole to mole ratio which comes from our balanced equation and then finally
converting our moles of NH3 to grams of NH3 using our molar mass of NH3 So starting with our given value with 4.21g of H2, we'll align that
with our molar mass of H2 so putting our grams and our grams and then on top
we'll put 1 mole of H2. Our grams of H2 would then cancel. Now that our grams of
H2 have cancelled we'll move on to moles of H2 and convert that to moles of NH3.
So we'll put the moles of H2 across from each other and where I got this 3 moles
of h2 was from our balanced equation. Since there's a 3 coefficient in our
balanced equation there's really 3 moles of H2 for every 2 moles of NH3 which
is exactly what I'm using here to change that moles of H2 to moles of NH3. Our
moles of H2 will then cancel. Now that our moles of H2 have cancelled and we're
at moles of NH3 then we can finally get to our last step which is getting to
grams of NH3. So align those moles of NH3
across from each other and put your molar mass of NH3 on top. Our moles of
NH3 would then cancel. Now that we finally have gotten to our grams of our
product from going from grams of H2 and working our way to grams of NH3, we'll
multiply straight across and divide by 2.02 times
3 and that'll give us 23.68g of NH3. Now let's
move on to step two which is our last step. The reactant that produces the
least amount of product is the limiting reactant. And now let's compare our
reactants and see which one produced the least amount of product. N2 produced
17.42g of NH3. And our other reactant H2 produced
23.68g of NH3. So our N2 produced the least amount
of product which was our NH3. So finally N2 is our limiting reactant.
Hey guys I created detailed notes with examples that show every single step to
find limiting reactants, excess reactants, theoretical yield, percent yield, actual
yield, all the yields. The link is in the description box make sure to check it
out. Now I know this seems like a long process but you could do this. Back when
I learned this I used to struggle with it too but with practice and persistence
you will absolutely pull through. Alright I'll see you in the next video, I'm
off to answer your comments now.

Using Avogadro’s Number | How to Pass Chemistry



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Learn how to convert particles, atoms, molecules and formula units all to moles! This video explains how to use Avogadro’s number as a conversion factor and …

Chemistry is fun. No, seriously! | Jordin Metz | TEDxTufts



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How do you feel about chemistry? If you dislike chemistry, or think it’s inaccessible, you’re not alone. Jordin Metz wants to break down the barriers to chemistry, …

Biomentors – AIIMS/ NEET 2020 Batch:Chemistry – General Organic Chemistry Lecture – 25



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1. Addition of hbr across the double bond of a alkene 2. Addition of hbr across the double bond of a alkene in the presence of peroxide 3. Addition of halogens …

Unit Conversion & The Metric System | How to Pass Chemistry



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Learn some helpful tricks on how to remember the metric system, and practice what you just learned to ace your exam! This video helps you understand how to …

Balancing Chemical Equations Step by Step Practice Problems | How to Pass Chemistry



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Life can be hard to balance, but balancing chemical equations doesn’t have to be! In this video, you will learn how to balance out chemical equations like a true …

Three Step Scientific Method



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Can you get the scientific method down to three steps? Think about it then watch this video! Subscribe! This is the fifth video in my new …

Hydrocarbon Derivatives: Crash Course Chemistry #43



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Functional groups? Functional groups within functional groups? Hank takes today’s Crash Course video to discuss some confusing ideas about Hydrocarbon Derivatives, but then makes it all make more sense.


Table of Contents

Alcohols 1:53
Hydroxyl Groups 3:51
Aldehydes 2:47
Carboxylic Acid 4:06
Acetone is a Ketone 4:43
Ethers and Esters 5:49
Amines 6:39


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رائحة القرفة والجيف المتعفنة، مركبات بإمكانها إزالة طلاء الأظافر والعمل بمثابة وقود للسيارة
أو إفقادنا الوعي أو التخلص من الصداع. كل هذه الأمور يمكن تحقيقها
بواسطة مركبات عضوية بسيطة ذات مجموعات وظيفية مختلفة ناتئة منها. أجل، قلت "مجموعات وظيفية"
وسوف نتحدث عنها اليوم. عندما بدأ علماء الكيمياء دراسة هذه الأمور لم يكونوا يعرفون دائماً
ما يميز مادة كيميائية عن أخرى، وإنما فقط أن مركبات معينة تتصرف على نحو
متماثل في كثير من الأحيان وإن كانت مختلفة. فبعضها تشبه رائحتها رائحة السمك
وبعضها ذات درجات غليان مرتفعة وبعضها تتفاعل بطرق متشابهة مع المركبات ذاتها. الآن بتنا نملك معرفة أفضل،
فنحن نعرف ما هي ومن أين تأتي ولماذا تتصرف
على النحو الذي تتصرف به. لقد تعمقنا في المعرفة
المتعلقة بأقوى أدوات الكيمياء العضوية. إنه لشعور رائع. غوصوا معنا في هذا الخليط المكون من الأسترات والأثيرات
والألدهيدات والأمينات والكحوليات، ولكن لا أعني أن تفعلوا ذلك بالمعنى الحرفي
فذلك سيكون مقرفًا للغاية وستموتون على الأرجح. حتى الآن، ناقشنا فقط المركبات العضوية
المتعلقة بالكربون والهيدروجين ولا شيء سواهما. نعم، الكربون والهيدروجين
هما عِماد الكيمياء العضوية، بل إن التولفيات أحادية وثنائية
وثلاثية الأبعاد لذرات الكربون هي عماد غالبية المركبات العضوية. ولكننا اليوم سنضيف لاعبَين جدد، وهما اثنان
من العناصر المفضلة لدي: الأكسجين والنيتروجين. باستخدام هذان العنصران الإضافيان سنتحدث
عن سبع مجموعات وظيفية مثيرة ومختلفة. ولكن أولاً، ما معنى "مجموعة وظيفية"؟
فهي تبدو لي مملة للغاية. الكيمياء العضوية هي هندسة بناء الكيمياء. فبها نحن لا ندرس المواد الكيميائية فحسب
بل ونصنعها أيضاً. ونحن نعرف أن مجموعات معينة
من الذرات المترابطة تعمل بطرق محددة للغاية. وبما أننا نعرف كيفية عمل هذه المجموعات
الوظيفية، فإننا – وبذلك أعني البشر، يمكنا الإضافة إليها أو الأخذ منها أو تعديلها
أو وصلها ببعضها بعضًا بطرق يمكن التنبؤ بها. وهكذا يمكننا صنع المركبات
التي نحتاج إليها سواء أكانت بسيطة مثل حمض أسيتيل ساليسيليك،
أي الأسبرين، أو معقدة أكثر مثل alpha – (5,6 – dimethylbenzimidazolyl)
cobamidcyanide، أو ما يعرف باسم فيتامين B12. جميل، أليس كذلك؟
عندما نتحدث عن المجموعات الوظيفية فإننا نركز على تفاصيل الجزيء الصغيرة درجة أن بقية الجزيء لا يعود ذو أهمية كبيرة، لذا فإننا نستخدم الحرف R للإشارة إلى البقية.
R تمثل أي جزء من الجزيء العضوي لا يهمنا كثيراً في الوقت الحالي. كما أننا أحيانًا نطلق
على القسم غير المهم اسم المجموعة R، وذلك لنميزها عن المجموعة الوظيفية
التي هي محط اهتمامنا. الآن وقد أمضيت 3 دقائق تقريباً
في التحدث إليكم، دعونا نلقي نظرة إلى ما يمكن للنيتروجين والأكسجين فعله
في المركب العضوي. المجموعة الوظيفية القائمة على الأكسجين
الأولى والأشهر هي الكحول: مجموعة O-H الطرفية ولا أعني بذلك أنها فتّاكة
وإن كان الإيثانول مميتاً وكذلك بعض أنواع الكحولات الأخرى
مثل الميثانول وهو مميت للغاية. بل هي طرفية بمعنى أنها تُنهي سلسلة كربون. ماذا يحدث عندما ننزع الهيدروجين
من مركب كحولي؟ ولا أعني بذلك تسبب الكحول بالجفاف للمرء،
فذلك أثر تناول المشروبات الكحولية، وإنما نزع الهيدروجين منه في تفاعل كيميائي، أي نزع الهيدروجين من الأكسجين
وإنشاء رابطة مزدوجة مع الكربون. ذلك الكحول منزوع الهيدروجين يسمى ألدهيد. الكحولات والألدهيدات تشترك بخصائص متماثلة
كثيرة بسبب الكهربية السلبية للأكسجين. الهيدروكربونات وحدها تكون مملة جدًا في الواقع. بالنظر إلى جدول الكهربية السلبية
يمكننا رؤية أن الفرق في الكهربية السلبية بين الكربون والهيدروجين هي 0،35 فقط. لذا، ليست هناك مناطق شحنات
موجبة أو سالبة كبيرة في الجزيئات. وعليه فإن هذه
الهيدروكربونات البسيطة غير قطبية وإلكتروناتها موزعة
بالتساوي في جميع أرجاء الجزيء، ولهذا لا يختلط الزيت بالماء كما تعلمون. ذرات الأكسجين تضفي بعض الإثارة، حيث تتكتل
الإلكترونات وروابط الهيدروجين والأكسجين في الكحولات قطبية إلى حد كبير حيث الفرق
في الكهربية السلبية بين O وH هو 1،22. لذا يحصل الأكسجين على دلتا سالبة
والهيدروجين على دلتا موجبة. وهذا لا يجعل الكحولات والألدهيدات
أكثر قابلية للذوبان في الماء فحسب وإنما أيضًا يغير تمامًا
نوع الكيمياء التي يمكن تطبيقها عليها. تحذير من دنوّ الارتباك! من الممكن إيجاد مجموعات وظيفية
داخل مجموعات وظيفية. رأينا اثنتين منها، فإذا كان جزيء OH جزءًا من
مجموعة وظيفية أكبر نشير إليه باسم هيدروكسيل وإذا ما شكل الكربون رابطة مزدوجة مع الأكسجين
ضمن مجموعة أكبر نسمي ذلك كربونيل. على سبيل المثال،
إذا ما كون كربونيل رابطًا مع هيدروكسيل فإن ذلك يُشكل حمض كربوكسيل. آمل أن تكونوا قد بدأتم تفهمون المصطلحات. انظروا إلى حمض الكربوكسيل، وإذا ما
فكرتم في الكهربية السلبية لذرتي الأكسجين يمكنك أن تتصوروا أن ذرة
الهيدروجين فيه لن تكون مثبّتة على نحو جيد، وعليه بإمكانها التفكك
في المحاليل جاعلًا المركب حمضًا. أحماض الكربوكسيل هي الجزء الحمضي في
الأحماض الأمينية، التي تتكون منها البروتينات والتي نتكون منها نحن.
لذا، فهي مهمة جدًا. حمض الكربوكسيل الأبسط والمعروف باسم حمض
الفورميك هو ما يجعل عضات النمل الناري لاسعة وبإضافة ذرة كربون واحدة
نحصل على حمض الخليك أو الخل، والذي حتى مع كونه مخففًا عندما نضعه في خزانات
المطبخ سيؤلم جدًا إذا ما دخل عين المرء. حمض الخليك
مثير للاهتمام أيضًا لأنه ذات يوم قام عالم كيمياء ذكي اسمه ليوبولد غميلين بانتزاع مجموعة OH
ووصل الكربونيل بمجموعة كربون أخرى. كانت النتيجة كربونيل غير طرفي، أو داخلي.
وقد أطلق على تلك المادة اسم أسيتون لأنه مشتق من حمض الخليك. أسيتون هو فقط اسم تلك المادة الكيميائية
وليس المجموعة الوظيفية ذاتها. ولنعرف اسم المجموعة نقص الألف
ونحول حرف السين إلى كاف ليصبح الاسم كيتون. لذا، عندما يكون لدينا كربونيل
وسط سلسلة كربون تكون تلك مجموعة كيتون وظيفية. الأسيتون يمتلك مجموعة كيتون،
واسمه أسيتون لأنه مشتق من حمض الخليك ألا وهو الخل، الذي هو
حمض الكربوكسيل الأكثر شيوعًا في المطبخ. أقسم لكم أنكم إذا أعدتم مشاهدة
هذه الحلقة فسوف تفهمون. الأسيتون بسبب تلك الرابطة المزدوجة قطبي وعليه
فإنه قابل للذوبان في الماء ورائع للتنظيف. روابط الهيدروجين بين الأكسجين والهيدروجين
الخارجي كافية لإبقاء الجزيء متماسكًا بحيث لا يكون غازيًا في درجة حرارة الغرفة. كما إنه مستقر بدرجة كافية
تحول دون أن يكون سامًا للغاية. بل الواقع إن دم كل منا
يحتوي على القليل من الأسيتون الآن، ولهذا هو آمن بدرجة كافية
لاستخدامه كمزيل لطلاء الأظافر، ولكنه مع ذلك غير مستقر لدرجة تجعلنا
نخاف من وضعه بالقرب من ألسنة لهب النيران. الآن بقي لدينا مجموعتان وظيفيتان
قائمتان على الأكسجين لنتحدث عنهما: وهاتان مجموعتان تمتلكان ذرات أكسجين
داخلية مرتبطة مباشرة بالكربونات. عندما ترون ذرة أكسجين في وسط سلسلة كهذه
فهي إما أثيرات وإما إسترات. إما أثير وإما إستر، إستر أو أثير، واحدة منهما، واحدة أو الأخرى.
أثير أو إستر. الأثيرات تمتلك ذرة أكسجين وحيدة
في وسط سلسلة الكربون، أما الإسترات فاسمها يوحي بأنها جمع لأنها تحتوي على ذرتي أكسجين، إحداهما في وسط السلسلة
والأخرى جزء من مجموعة كربونيل. الإسترات أشبه بكيتون مخلوط بأثير، بل إنكم إذا ما نظرتم إلى المجموعات الوظيفية
الأكسجينية سترون إنها متقاربة جدًا. الألدهيدات ما هي
إلا كحولات منزوعة الهيدروجين، والكيتونات ما هي إلا ألدهيدات مرتبطة بمجموعتي
R في كلا الطرفين بدلًا من هيدروجين في طرف واحد في حين أن أحماض الكربوكسيل هي كيتونات
مرتبطة بمجموعة OH بدلاً من مجموعة R، والأثيرات هي مجرد كحولات مرتبطة
بمجموعة R بدلاً من ذرة هيدروجين. وعدتكم ببعض النيتروجين في بداية الحلقة
وأنا أعتذر لجميع عشاق النيتروجين لأنني لم أتحدث عنه حتى الآن. لنقل فحسب أن الأمين بسيط للغاية،
فهو مجرد مجموعة NH2 طرفية. تذكروا أن الأمونيا هو NH3، وعليه فإن حرفي
"أم" في اسم أمونيا يلتصق بمجموعة الأمين. الأمينات كريهة الرائحة للغاية، واثنان من
الأمينات المفضلة لدي هما بوتْرِيسين وكادافيرين. أجل، هما يوجدان بكثرة
في جيف الحيوانات النافقة المتعفنة، وأجل، رائحتهما كريهة لأبعد الحدود. وتلك هي المجموعات الوظيفية السبعة
التي سنتحدث عنها، كان هذا ممتعًا للغاية، على الأقل بالنسبة إلي، ولكنني أعترف
بأنني ذو اهتمامات غريبة بعض الشيء. المركبات العضوية التي تتضمن هذه المجموعات
الوظيفية لها أسماء متنوعة ورائعة. كحول الخشب، سينامالديهيد، كادافيرين. أسماء جميلة، صح؟ في الواقع، يريد الكيميائيون
أسماء مركبات تزودهم بأكثر من مجرد التسلية فهم أذكى من ذلك. ولهذا فإننا في الأسبوع
القادم سنتحدث عن طريقة تسمية هذه المركبات، وعن طريقة معرفة ما هو المركب
إذا ما عرفنا اسمه. شكرًا لمشاهدتكم هذه الحلقة
من Crash Course Chemistry. إذا كنتم منتبهين فقد تعلمتم أن الكحولات هي
مركبات عضوية تحتوي على مجموعات هيدروكسيل، وإذا نزعتم الهيدروجين منها تتحول إلى كربونيل
لتصبح كحولًا أو ألدهيد منزوع الهيدروجين. وإذا ما ارتبط كربونيل بهيدروكسيل فإن المجموعة
الوظيفية تصبح خلّية فيكون حمض كربوكسيل، وأكثرها شيوعًا حامض الخليك الذي إذا ما استبدلت
الهيدروكسيل فيه بمجموعة ميثيل يصبح أسيتون، وإذا ما استبدلنا حرف السين بكاف
يصبح كيتون وهو الأسيتون في الأساس. أخيرًا، سلسلة الكربون التي تحتوي على ذرة
أكسجين داخلية هي إما أثير وإما إستر وتكون إستر فقط
إذا ما كانت مرتبطة بمجموعة كربونيل. وبالطبع فإن أي شيء
يحتوي مجموعة NH2 هو أمين. هذه الحلقة من تأليفي أنا، هانك غرين وهي من تنقيح بلايك ديباستينو
ومستشارنا الكيميائي هو الدكتور هايكو لانغنر. الحلقة من تصوير ومونتاج وإخراج نيكولاس جنكنز.
مشرف النص ومصمم الصوت هو مايكل أراندا وفريق الرسومات الجرافيكية هو Thought Café.

Chemistry (2011) 8 series



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Chemistry (2011) – 3 series.

Chemistry (2011) – 3 series. Chemistry (2011) – 9 series. Chemistry (2011) – 9 series. Passions ignite and the ual sparks fly in this sultry series from Cinemax, which just proves that.

Chemistry (2011) -12 series.

a las latas tras las a las leyes las luchas tras las las luchas tras las a tras las i tras las i las luchas las luchas las loas tras las tras las las leonas más tras las tras lo tras las tras las a las leyes tras las a a tras las i las leonas tras las tras las las luchas sus hijas tras las las luchas a tras las tras las a a mí me a tras las las luchas a tras las i tras las las luchas tras las tras las las luchas las luchas tras las tras las las luchas las loas tras las tras las a m tras las tras las bush lo lo a tras las las luchas las luchas las loas tras las las lajas a a a tras las a a tras las i bush tras las a lo a tras las tras las a tras las i tras las tras las tras las las luchas tras las tras las las leonas tras las las luchas tras las tras las tras las las luchas las loas tras las las loas las loas las luchas tras las las loas tras las a tras las tras las bush lo lo a tras las las luchas las luchas las loas tras lo bush es las lolas tras lo tras las tras las a las leyes tras las a a tras lo tras las a las leyes tras las las loas tras las tras las a las leonas i tras las i las luchas tras las las luchas

PhD career in Denmark – Li from China (chemistry and molecular biology)



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Li from China is pursuing her PhD in organic chemistry at the University of Southern Denmark. In this video she talks about her project …

Biology in Minutes: The Chemistry of Life



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The is a condensed version of the lecture I normally give to my students for the chapter called Chemistry of Life.

Atoms, Molecules, and the Scientific Method



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what's up everybody so in this video I'd like to introduce you to the wonderful beautiful subject that is chemistry so I'm going to be talking about atoms and molecules in this video I'm also going to touch upon the scientific method so I think a good place to start when introducing any kind of subject is to simply define the subject and certainly there are a lot of definitions of chemistry out there this is just one definition that I pulled from dictionary.com and it states that chemistry is the science that deals with the composition and properties of substances in various elementary forms of matter so based upon that definition we can conclude that chemistry is a very broad very large very nebulous and very all-encompassing type of science so as we look at this image here this is an image of a beaker pho by the green transparent liquid that seems to be giving off smoke so with chemistry we can ask ourselves and hopefully answer a ton of different questions about this image so for instance why is this liquid green why is it transparent why is it giving off smoke what's going on within that liquid to make it give off smoke like that what about the smoke itself what is the smoke made of what is what is it about the smoke that makes it float around like that and what about the beaker the beaker is made of glass what is glass what is it about glass that makes it break when you drop it what is it about glass that makes it so unreactive to so many substances to the point where we can carry out a wide variety of chemical reactions inside of it and it'll be largely unaffected so these are you know questions that chemistry attempts to answer and one of the things one of the common themes that helps us answer these questions is the idea that the behavior of matter is dependent upon the properties of the individual atoms and molecules that compose the matter so with that I'd like to talk about atoms and molecules a little bit so what an atom is is basically it's just a basic unit of matter and molecules are basically just a step up from atoms at what a molecule is is it's two or more atoms joined together in a specific arrangement so that theme that I mentioned earlier the fact that the behavior of matter is dependent upon the properties of its constituent atoms and molecules I'd like to demonstrate a little bit that a little bit further by talking about carbon monoxide so carbon monoxide is a fairly simple molecule it is composed of a carbon atom which is shown here in the black and that carbon atom is bonded to an oxygen atom which is shown here in red so the fact that carbon monoxide is a poisonous gas is fairly common knowledge but what we don't all know is why carbon monoxide is poisonous and the answer to this question has everything to do with a molecule on our bodies called hemoglobin so what hemoglobin is is it's a protein and basically what proteins are is they are these very large very complex molecules that carry out specific biological functions so some proteins are structural meaning they are building blocks for even larger units other proteins such as hemoglobin here are actually involved in transporting substances and hemoglobin is involved in transporting oxygen molecules which are composed of two oxygen atoms so oxygen will do is it will come in and it'll bind to hemoglobin right here this is actually one of the four locations in a mcglothen where oxygen combined it will bind to hemoglobin and then at some point later it'll be released from hemoglobin wherever it is needed and where carbon monoxide comes in is carbon monoxide actually binds to hemoglobin in that same spot more effectively than oxygen does so when someone dies from carbon monoxide poisoning they're they're not necessarily dying directly from the carbon monoxide what they're dying from is the lack of oxygen that's going to their tissues which is caused by carbon monoxide taking up too many of those binding sites in hemoglobin so the lesson for the day if anything would be you know don't leave your car on in an enclosed garage so a molecule is closely related to carbon monoxide called carbon dioxide which is composed of a carbon atom in two oxygen atoms is not nearly as toxic as carbon monoxide and the reason why is because that extra oxygen atom severely limits the ability of the molecule to bind to hemoglobin so just the one oxygen atom just one atom has a very very profound effect upon the upon the behavior of these substances and with that I'd like to segue a little bit into I'd like to talk a little bit about the scientific method so this gentleman over here on the right this guy his name is Francois Marie reveled and I'm not going to attempt the French accent because it's atrocious anyway this guy made observations he employed the scientific method what he did was he studied solutions which is which are basically just mixtures and he found that that these mixtures the more concentrated they were the lower their freezing points were so what he did was he made observations about the physical world and that's a key idea about the scientific method is that it is empirical meaning it is based on observation and experiment so what scientists generally do is they make observations after observations after observations and based upon these observations will formulate what's called a hypothesis or they'll formulate several hypotheses hypothesis is singular hypotheses is the plural form of the word and what a hypothesis is it's basically a a tentative explanation of a certain phenomenon that has yet to be tested and a good hypothesis is falsifiable meaning it can be supported or refuted by scientific experiments so next in line comes the experiments and those are just highly controlled procedures designed to test hypotheses and generate further observations so once these further observations are generated that can lead to the formation of a scientific law and what a scientific law is is it's a brief statement that summarizes what nature does how nature behaves and it it summarizes past observations than it predicts future observations and closely related to scientific laws are theories so scientific laws are like the what and theories are like the why so laws don't really explain why a phenomenon occurs that's what theories do and I'd like to talk a little bit more about theories a little bit so theories scientific theories have strong experimental support and the truth of the matter is that we can't do any better than a theory in science theories are as close to the truth as possible the only thing better than a theory is a better theory so when someone throws around the term just a theory like it's easily dismissible a statement like that really reveals a very profound misunderstanding of how scientific theory works I mean the idea that matter is composed of atoms is itself just a theory but it has hundreds of years of scientific evidence to support it so whenever someone says just a theory reach over and smack them in the face and tell him to watch this video all right hope this was helpful and good luck out there

CH110 1.1 Chemistry & 1.2 The Scientific Method



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An introduction to chemistry and the scientific method. This is from Sections 1.1 & 1.2 in Chemistry: An Atoms First Approach by Zumdahl & Zumdahl.

Power tips for ISCE/ ISC students for Class XII Maths



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poly Karim 4/12 ICSC maths what are the important topics that we should focus on so as you know the question paper is already divided into three sections to come into the first section that is sectioning so our first question compulsory so out of the rest of the questions you have to attend five questions so in that eight questions you have the choice right so the main important topics in that eight questions is that probability determinants and mattresses correlation and regression and calculates so this as a main important topics you need to focus on through score value so come into the section B and section C you have the choice of attempting to questions out of three either from B or C it is in Madinah so the easiest topic in Section B or Section C is vectors and 3d geometry so if you can just prepare well in these two chapters you get your shot and get twenty marks definitely now that we're aware of the important supressing sections ABC so in Section a we have talked about determinants and mattresses so in determinants you need to concentrate on properties of determinants and in mattresses you need to concentrate on inverse of matrix types of matrices and the solutions of system of equations on both determinants and magazines come to the next one that is probability the questions are mainly based on conditional probability that is more important in that and in calculus it turns out to part that is differential calculus and integral calculus in differential calculus you need to more concentrate on variable separable methods and homogeneous and non homogeneous systems and the equations that can be reducible to the homogeneous and non-vocal genius coming to the calculus part it can serve two sections that is differential calculus and integral calculus and differential calculus you need to concentrate on variable separable methods and the equations that are reducible to variables available method by solving that method the other part is that normal non and homogeneous equations and equations which are reducible to homogeneous equations and linear differential equations forms and come into the in d integral calculus part so you need to concentrate on partial fractions integrals which has all very marginal fractions and integral by parts that forms so etc you need to concentrate on these areas so the next part is correlation and regression so in this you can follow the pattern that is given from the previous years the more important questions are based more based on the formula given and come into the section B and C the easiest chapter to cover in this is vectors and 3d geometry so in vectors you need to concentrate on the scalar triple point back to triple product and scalar triple product and as well as the formulae that are style dual cosine rule the deviations of these formulae also so in 3d geometry so you need to mainly concentrate on equation of lines angle between lines and the distance between these two lines so coming to the plane part or in 3d geometry plane different forms of equations of plane this is very important and the distance between a point and the plane that is also important you have got the formula in the 3d geometry if you can just learn those formulas you can directly apply them and start with the questions so these very definitely help you

Commentary Lecture Two: The Chemical History of a Candle – Brightness of the Flame



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Bill Hammack & Don DeCoste highlight the key points of Lecture Two of Michael Faraday’s lectures on The Chemical History of a Candle. A free companion book helps modern viewers understand each lecture — details at — as does this commentary track and closed captions for each lecture.

►Free Companion book to this video series

Text of Every Lecture | Essential Background | Guides to Every Lecture | Teaching Guide & Student Activities

In these lectures Michael Faraday’s careful examination of a burning candle reveals the fundamental concepts of chemistry, while at the same time superbly demonstrating the scientific method. In this lecture Faraday reveals why a candle’s flame is bright. To do this he investigates the properties of the flame.

LINKS TO OTHER VIDEOS IN THIS SERIES
► Lectures
(1/6) Introduction to Michael Faraday’s Chemical History of a Candle

(2/6) Lecture One: A Candle: Sources of its Flame

(3/6) Lecture Two: Brightness of the Flame

(4/6) Lecture Three: Products of Combustion

(5/6) Lecture Four: The Nature of the Atmosphere

(6/6) Lecture Five: Respiration & its Analogy to the Burning of a Candle

► Bonus Videos: Lectures with Commentary
Lecture One: A Candle: Sources of its Flame (Commentary version)

Lecture Two: Brightness of the Flame (Commentary version)

Lecture Three: Products of Combustion (Commentary version)

Lecture Four: The Nature of the Atmosphere (Commentary version)

Lecture Five: Respiration & its Analogy to the Burning of a Candle (Commentary version)

►Subscribe now!
►Become an advanced viewer of Engineer Guy videos – help evaluate early drafts

COMPANION BOOK DETAILS
The companion book is available as an ebook, in paperback and hardcover — and for free as a PDF. Details on all versions are at

Michael Faraday’s The Chemical History of a Candle
with Guides to the Lectures, Teaching Guides & Student Activities
Bill Hammack & Don DeCoste
190 pages | 5 x 8 | 14 illustrations
Hardcover (Casebound) | ISBN 978-0-9838661-8-0 | $24.95
Paper| ISBN 978-1-945441-00-4| $11.99
eBook | ISBN 978-0-9839661-9-7 | $3.99
Audience: 01 — General Trade
Subjects
SCI013000 SCIENCE / Chemistry / General
SCI028000 SCIENCE / Experiments & Projects
SCI000000 SCIENCE / General
EDU029030 EDUCATION / Teaching Methods & Materials / Science & Technology

This book introduces modern readers to Michael Faraday’s great nineteenth-century lectures on The Chemical History of a Candle. This companion to the YouTube series contains supplemental material to help readers appreciate Faraday’s key insight that “there is no more open door by which you can enter into the study of science than by considering the physical phenomena of a candle.” Through a careful examination of a burning candle, Faraday’s lectures introduce readers to the concepts of mass, density, heat conduction, capillary action, and convection currents. They demonstrate the difference between chemical and physical processes, such as melting, vaporization, incandescence, and all types of combustion. And the lectures reveal the properties of hydrogen, oxygen, nitrogen, and carbon dioxide, including their relative masses and the makeup of the atmosphere. The lectures wrap up with a grand, and startling, analogy: by understanding the chemical behavior of a candle the reader can grasp the basics of respiration. To help readers understand Faraday’s key points this book has an “Essential Background” section that explains in modern terms how a candle works, introductory guides for each lecture written in contemporary language, and seven student activities with teaching guides.

Author Bios
Bill Hammack is a Professor of Chemical & Biomolecular Engineering at the University of Illinois—Urbana, where he focuses on educating the public about engineering and science. He is the creator and host of the popular YouTube channel engineerguyvideo.

Don DeCoste is a Specialist in Education in the Department of Chemistry at the University of Illinois—Urbana, where he teaches freshmen and pre-service high school chemistry teachers. He is the co-author of four chemistry textbooks.

Bill: I’m Bill Hammack . . . Don: . . . and I’m Don DeCoste . . . Bill: . . . and we created this lecture series
Michael Faraday’s The Chemical History of a Candle and this is a commentary track to
just kind of deepen or enrich the lectures and I would suggest that if possible you have
the subtitles for the lectures turned on. Don: In the first lecture, Faraday gave us
an overview of how a candle works. Now let’s listen to Faraday’s words about the subject
of Lecture Two: Michael Faraday: What happens in any particular
part of the flame; why it happens; what it does in happening and where, after all, the
whole candle goes to. Bill: Throughout this lecture, Michael Faraday
focuses on the properties of the flame of a burning candle, using those properties to
understand how a candle works. Now, what’s interesting is the number of tools he creates
to probe the flame. We normally think of sophisticated scientific instruments like microscopes or
spectroscopes or balances, but Faraday’s simple tools are just as specialized and of
course that’s part of science to invent or create tools that let us see the invisible
or to quantify nature. Don: And this is what one of the things that
makes chemistry a difficult subject especially when you’re first studying it, and that
is many of the properties are invisible. Now, you see here, that he’s using a specially
shaped glass tool to capture what he calls, the wax of the candle made into a vaporous
fluid. Bill: At this point Faraday makes a distinction
between a gas and a vapor noting that a gas is permanent and a vapor can be condensed, at least at the pressure and temperature of interest. But the larger issue is that he
points out that science makes use of precise terminology. Now that said, we are going to
take Faraday to task in a few minutes for some imprecise usage of the word ‘“air”
but more on that in a moment. Don: You know there’s a couple of different
ways to see things . . . as Bill mentioned you can make tools to do this . . . you can
also take things out of context and what Faraday is going to do next is he’s going to take
a large sample of wax and heat it, not burning it like a candle but heating it in
a flask. This is something deep here. He’s going to make an assumption that the sum of
the parts equals the whole and this is a type of a reductionism. Bill: Let’s listen here to the extent that
Michael Faraday uses reductionism. Michael Faraday: This, then, is exactly the
same kind of vapor as we have in the middle of the candle. Don: Of course, there is a limit to this analogy
as to all analogies. For example, why does the vapor flame out in the flask but not in
the candle. The idea here is that it’s not exactly like a candle. Bill: Now this is one of our favorite demonstrations,
it’s truly stunning. He shows clearly that it’s the vapor that ignites. And he mentions
that production and combustion of the vapor occur in two different parts of the flame
and he says this in a single sentence but it’s really a big deal. Don: The key here is to note where the tube
is positioned in the flame. It’s placed in a point where the production of the vapor
is occurring so that he is able to light the vapor as it comes up at the top of the tube. Bill: So this great demonstration really shows
that there are different parts of the flame that it’s not homogeneous. In fact, watch
what happens when he moves the tube. Bill: So what he’s done is, moved his tube
from the place of the production of vapor to the place where the combustion has occurred
and so the vapor is spent and so won’t relight. Don: And it was at this point that Michael
Faraday mentioned the intense chemical action with which the air meets the vapor in the
candle flame. This is the first time he is really getting it into the chemistry. Bill: So now he’s going to move from the
production and combustion of vapor to show us about the temperature distribution in the
flame. Bill: So notice here that he’s going to
use another tool, just a simple tool but it’s extremely effective. And this is another tool
that makes the invisible visible. We would think that the whole flame was hot, yet it
isn’t homogenous in temperature. The heat generated by the chemical reaction takes place
in only parts of the flame where the dark ring appears. Don: Faraday mentions again the chemistry
happening between the air and the vapor. But we want to listen carefully to his words because
there’s a little bit of imprecision in them that we want to talk about later. Michael Faraday: Air is absolutely necessary
for combustion and what is more, I must have you understand that fresh air is necessary
or else we should be imperfect in our reasoning and our experiments. Bill: So the problem here is the use of the
term “fresh air.” What exactly does this mean? I mean we know today that what he’s
trying to get to is the amount of oxygen that’s in the air but it’s kind of implies that
regular air or normal air doesn’t have oxygen in it. So, let’s listen to what he says
next which is a little bit better. Michael Faraday: The jar is full of air, partly
changed, partly not changed but it does not contain sufficient of the fresh air which
is necessary for the combustion of a candle. Don: And this is better, of course, because
Faraday uses “some changed, some not changed” for the air showing that there’s a chemical
reaction that’s occurring but he still uses the phrase “fresh air” and he does this
because he doesn’t want to pre-judge the idea that there’s oxygen in the air. Bill: What Faraday does as a teacher here
is very interesting. He uses this imprecise metaphor of fresh air, so he doesn’t have
to introduce a new topic yet. Now, let’s watch in this next section, how he returns
to that notion of reductionism. Michael Faraday: Here is a larger wick made
from those cotton balls. All these things are the same as candles after all. Don: So notice he’s saying, “all these
things are the same as candles” which means that the cotton balls are the same as candles.
But of course, they’re not. Now this is one of that really I think subtle parts of
science . . . we use models to capture the essential physical phenomenon but what we
have to do as scientists is we have to know how far to take a model and then we have to
know when it falls apart. Now, his goal here is to reduce the amount of oxygen that can
get to the burning cotton. Now, he can’t we reduce that amount here like he will soon
with the Bunsen burner so he creates this giant flame that cannot be fed well enough
from the surrounding air. Don: So this means that the oxygen is limiting.
Now, earlier on he showed us that we need something in the air which we know is oxygen
by putting the jar over the top of the candle and now he shows us that without enough oxygen,
there’s incomplete combustion. Bill: Now what Faraday did here was very interesting.
Or, more to point, what he didn’t do. He did show us the black smoke. He didn’t tell
us what that black smoke is. We probably have guessed that it’s carbon particles. And
today we would just say, look, I’m going to make carbon in the flame and then we will
tell you that the carbon makes the candle glow and Faraday inverts this process. He
puts the observation first. He says a candle glows, why does it glow, and then he goes
back and looks at what the black in the flame means and shows that it’s carbon particles
that glow. Don: And so, up to this point Faraday has
done a few things. One, he started by showing us that the flame is not homogenous with respect
to the chemical action. There are different places of production of vapor and combustion
of vapor and he showed us that it is not homogeneous with respect to temperature . . . there’s
a hottest part of the flame. Now in both of those cases we couldn’t really see them
and he used tools to do this. Now what he’s going to do is, he’s going to show us that
the flame is not homogeneous with respect to brightness which we could see, although
we have to really be observant to do that. And he is going to discuss this by talking
about things that burn with a flame and not with a flame. And he’s playing a little
bit fast and loose here with the word burn, but again, a little imprecision to get to
a larger point, I think he is justified. In this case, the chemical reaction of the gunpowder
with the oxygen produces the heat to form a flame and the iron particles are heated
until they glow which we call incandescence. Now, of course he’s going to show us in
a little bit that the carbon particles that are in the flame are what’s glowing and,
of course, there’s carbon particles in gunpowder. So, he’s really adding the iron fillings
here for effect. Now the last thing that he mentions here as well is that the oil, the
gas, the candle, all of these that we use for illumination, he uses the phrase, “the
fitness depends on these different kinds of combustion” which is a really nice way then
of expanding this to more than just a candle. Bill: So when we were recording the lecturers
we noticed that this demonstration was redundant, it contained really the information of the
previous demonstration and we did take a number of these redundant demonstrations out, but
we’ve really liked this one and it highlights just how great a showman Michael Faraday was
because this produces just an absolutely brilliant flame that would have delighted his audience. Don: So what’s coming up next is a kind
of a continuation of what he had done before. Bill had mentioned earlier how it is interesting
how Faraday starts with an observation and then goes in search of how to explain that
observation. The one observation was when he used the cotton balls to make a large flame
we had restricted oxygen and we noticed that we see some black smoke. Now where is that
black smoke coming from? Now Faraday uses this simple tool of this glass tube to place
it inside a part of the flame, in this case, the brightest part of the flame and we can
see that the black smoke is coming from there. We now know of course that the black smoke
is carbon and the carbon actually reacts with the oxygen in the air when it meets the interface
of the flame and the air. Bill: So here, Faraday gives a little chemistry
lesson, a nice conservation of mass. He points out that the carbon that’s coming out of
the candle and the smoke was the carbon that was originally in the candle and he makes
an observation that shows how science links together all sorts of observations. He mentions
the soot that’s in London . . . that’s also carbon. So carbon is carbon. That’s
the theme that will see come up a couple of times particularly when he talks about water. Don: And so, here Faraday is reminding us
that it’s the glowing carbon particles that give us the bright part of the flame just
as he showed the iron filings were glowing in the gunpowder. Bill: At this point, Michael Faraday sums
up what he concludes from his experiment. So let’s just listen to him. Michael Faraday: What I have to say is applicable
to all substances whether they burn or whether they do not burn that they are exceedingly
bright if they retain their solid form and that is is to this presence of solid particles
in the candle flame that it owes its brilliancy. Bill: So Faraday here is using reductionism.
He said that carbon particles glow. So, he’s going to isolate the carbon and interestingly
what he does here is he makes it human size, he’s got a large chunk of carbon and when
he puts it in a flame you can see that it glows and this, as he says, is what gives
the candle it’s brightness. Don: Let’s listen to Faraday comment on
a kind of counterintuitive aspect of beauty and nature and we’ll talk about it a bit
after. Michael Faraday: Is it not beautiful to think
that such a process is going on and it’s such a dirty thing as charcoal can become
so incandescent? You see it comes to this. That all bright flames
contain these solid particles. All things that burn and produce solid particles either
during the time they are burning as in the candle or immediately after being burnt as
in the case of the gunpowder and iron filings, all these things give us this glorious and
beautiful light. Bill: So, when Faraday says a dirty thing
like charcoal has beauty, he’s really echoing some thoughts that he had in the first lecture where he looked at decorative candles which most people thought were beautiful but they were bad burning and argued that a normal candle is a beautiful thing. And also there
is a subtle reminder here that science gives us a unified way to look at the natural world. Don: So this demonstration kind of like the
lycopodium demonstration is a little bit redundant at this point. He’s talked about the brightness of flames coming from the solid particles. But again it’s a spectacular demonstration
so Faraday being the showman wants us to see this. But he also does something interesting from an educational aspect and he asks the audience: “I’ve given you all the tools
now, you can reason your way through this. Does this flame contain particles or not?” Bill: Here Faraday burns propane which of
course provides the carbon in a Bunsen burner and he’s allowed very little oxygen into
it and so what happens is you get this very yellow flame because of the carbon particles. Bill: Now watch what happens if he allows
a lot of oxygen into the flame . . . all of the carbon burns so he no longer has carbon particles, so he no longer has the yellow flame, but instead has just a blue flame. Don: So, it’s interesting here that Faraday
now is using this Bunsen burner as a tool although not as we normally use it in the
lab. He’s doing this to kind of sum up two of the key observations that he’s made.
One, the oxygen controls the amount of particles that we have in the flame. And two, it’s
the particles here that glow brightly and give the flame it’s brightness. So, he’s
using this then to control these variables. Don: So here Faraday is again making the invisible
visible. He’s already shown us this once before covering the candle with a jar. But
before he focused on the flame and now he’s focusing on the cloudiness inside the glass
jar and he’s doing that because it’s the product of the candle that actually makes
this cloudiness. He’s hinted a little bit . . . he’s talked about this invisible substance
when he talked about the carbon burning. He’ll talk about carbon dioxide in Lecture Four but
what he’s really hinting at now is the fact that water is one of the products of combustion
and he does this with a spoon, something you can do at home. Bill: And water is the subject of the next
lecture. Faraday looks at it thoroughly in Lecture Three and I hope you will join us for
commentary on that lecture. I’m Bill Hammack Don: . . . and I’m Don DeCoste . . . Bill: . . . and thanks for listening.

Atomic Bonding Song



Views:499187|Rating:4.66|View Time:4:49Minutes|Likes:7257|Dislikes:535
Starring: Christie Wykes as Chlorine, Carbon, and Sodium
Director of Photography: Sean McCallum
Gravity (John Mayer Cover)
I’m Atoms (Jason Mraz Cover)
Electricity (Jet Cover)
Experiments A Cappella

在我的價電子殼上 一個原子自己帶一個價電子 我尋求興高采烈 通過氧化 我一直覺得自己不完整 一個害羞的十八歲電子 我有最高的 電子親和力 如果我們交換這個電子(Na身上的那顆) 我們都將實現惰性氣體組態 我們將釋放位能 作為離子,你會看到 鍵結 由金屬和非金屬製成 我帶正電 我帶負電 吸引力創造了這種鍵結 由金屬和非金屬製成 離子鍵 共價鍵 金屬的,這些是化學的鍵結 八隅體規則說原子就像有八個的 處於最外層的電子。 我會和你分享我的(價電子) 我會和你分享(價電子) 如果我們都共享這六個電子 我們都將實現惰性氣體組態 我們將釋放位能 將會有共價~ 鍵 電負度~ 非金屬都差不多 因此,我們分享這種化學鍵 電負度 離子鍵 共價鍵 金屬的,這些是化學的鍵結 自由~ 電子的四周 相互吸引力很大 通過這種方式 我會留下來 和你一起結晶 我們的鍵結 離子鍵 共價鍵 金屬的 這些是化學的鍵結

Absorption & Emission Spectrum, Hydrogen Spectrum -Atomic Spectrum | Class 11 Chemistry | Ashwin Sir



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Video by our Chemistry Expert – Ashwin Sir
Learn about Atomic Spectrum, emission and absorption spectrum, spectrum of light and the atomic spectrum of Hydrogen. Videos by top IIT JEE teachers who are also IIT JEE top rankers.

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Spectrum of light –
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Balmer Series –
Rydberg’s expression and other spectral lines-

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Radioactive Boy Scout – How Teen David Hahn Built a Nuclear Reactor



Views:6630792|Rating:4.54|View Time:13:57Minutes|Likes:112020|Dislikes:11325
Think a teenager can’t build a nuclear breeder reactor without getting caught? Think again. David Hahn, aka the Radioactive Boy Scout, was able to easily collect radioactive and highly dangerous materials to experiment with nuclear energy. Just when you think the story can’t get crazier, it does.

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David Han also known as the radioactive Boy Scout built a nuclear reactor in his mom's backyard out of common household items when he was 17 as shocking as that is that a teenager built a nuclear reactor at his mom's house the story of what made it all possible and the terrible mess it created is even more insane David was born just outside of Detroit Michigan in 1976 his parents who both worked for General Motors when they employed basically everyone in the area unfortunately divorced when David was still very young growing up he spent most of his time living at his dad and stepmoms house and lived on the weekends at his biological mom Patty's house when he was 10 years old his grandfather his stepmoms dad gave David a seemingly harmless gift which would start this soon-to-be out-of-control train of events in motion the gift was a book called the golden book of chemistry experiments and David was instantly obsessed David set up a small laboratory in his bedroom at his father's house but this wasn't like the pretend fun beakers full of water with food coloring in them type laboratory you might normally find in a kid's room no David bought legit beakers Bunsen burners test tubes and lined his shelves with chemistry books and volumes and volumes of the Encyclopedia by 14 when most are messing around with relatively harmless experiments or making baking soda volcanoes David had fabricated nitroglycerine David was also in the Boy Scouts in one-time show up to a Boy Scout camping trip with a bright orange face caused by an overdose of cam facts intent which he claimed he was taking to test methods for artificial tanning he was literally performing experiments on himself when he was just a kid on that same trip David along with some of his fellow Scouts blew a hole in one of their tents by igniting a stockpile of magnesium David had brought along to make fireworks despite the fact that David's father and stepmom are frequently alarmed by small explosions and chemical spills in their son's bedroom they didn't put a stop to his experimentation they just made a move his lab setup down to the basement as they were tired of him destroying his room pockmarking the walls with various explosions and spilling chemicals all over the carpet this is likely where all of this should have been put to a stop but it wasn't and David started heading down an even more dangerous path with his experiments banishing him to the basement was actually the opposite of punishing david now he just had more room and more privacy to conduct his experiments he only became more obsessed and more focused on chemistry he held down a variety of afterschool jobs just so he could make money to buy materials to mess with in his laboratory soon David would do something that would cause another change in location for his laboratory he had gotten a hold of a bunch of red phosphorous basically match heads and he placed it in a glass container and started hammering it with a screwdriver and yeah it exploded he injured his hands and arms badly and he had to have glass which exploded from the container removed from his eyes he had glass shards explode into his eyes because of course David wasn't wearing goggles again this seems like the time any parent or guardian would take away the chemistry kit but in this case David just moved his lab to his biological mother's potting shed in her backyard and that's where things started to get radioactive David would spend countless hours in the shed doing god-knows-what but both his mother and his mother's boyfriend never cared to check in on him they were both just in awe of his work ethic and dedication one day David's mom's boyfriend Michael did ask him what he was up to and David responded by saying you know someday we're going to run out of oil and here we go David's dad thought that his son needed to take his obsessive work ethic and put it towards something useful becoming an Eagle Scout Eagle Scouts need to earn 21 merit badges across a variety of disciplines some are mandatory but a few of them are Scouts choice as it were you could earn a badge in business or woodworking for example but David went ahead and opted to earn a badge in atomic energy which raised a red flag to absolutely no one even though David was the only Scout in the troops history to go after that merit badge any out of history of blowing himself up David put together an information pamphlet with the help of several utility companies to go towards earning his atomic energy badge the general gist of the pamphlet was that nuclear energy was good nuclear energy was vital and nuclear energy needed to be studied more he also made a chart explaining nuclear fission and a harmless toy model nuclear reactor using a juice can coathangers soda straws kitchen matches in a rubber band david also had the opportunity to visit a hospital's radiology unit to learn how they use radioactive isotopes and in the end David was awarded his atomic energy merit badge on May 10th 1991 just a few months before his 15th birthday not content with his fake nuclear reactor he made out of soda cans and coat hangers David decided he was going to build an actual radioactive nuclear power reactor in his mom's potting shed and guess what he did but to do so David would have to overcome some obstacles and a few more adults would have to not ask any questions David set out to build what's known as a breeder reactor which is a specific type of nuclear reactor that not only generates power it continuously creates new fuel for itself in an endless self-sustaining cycle in theory solving the world's energy problem there were a few functioning large-scale breeder reactors built but they were all either shut down for not actually producing cost-effective energy or they had partial meltdowns before we get into the type of stuff David would have to acquire to build a breeder reactor here's a very simplified explanation of the science behind it all reactors rely on a bunch of a naturally radioactive element typically uranium or plutonium as the fuel for a sustained chain of reactions known as fission fission occurs when a neutron combines with the nucleus of a radioisotope like uranium and transforms it into a new highly unstable form of uranium that immediately splits in half creating a massive amount of energy and causing a chain reaction of endless combining and splitting and the releasing of energy anyway if that went over your head don't worry about it the point is david would have to get his hands on a bunch of legitimately radioactive and extremely dangerous materials which should basically be impossible right nope not really here's how we did it and be warned it will shake your faith in just about everything quite simply David just pretended to be a college professor writing letters and making phone calls to places like the Nuclear Regulatory Commission the NRC the American nuclear Society the Edison Electric Institute and the atomic industrial forum and then nobody decided to double-check David's made-up identity over the phone a rep from the Nuclear Regulatory Commission ended up basically walking David through the end entire process of obtaining and isolating radioactive isotopes normally no one person would be able to legally obtain a large enough amount of the radioactive materials needed to pose any sort of danger but this isn't a normal situation this is David frickin Hong he was an Eagle Scout David later said the NRC gave me all the information I needed all I had to do is go out and get the materials and he did from his conversations with government officials and by looking over old Boy Scout booklets David learned that you could find small amounts of radioactive elements in smoke detectors old luminous clocks painted with a radioactive paint that made the numbers on the clock low and old camping lanterns just one of each of these items wouldn't cut it David would need a large amount more than any normal person would ever purchase to get what he needed so David just kept on pretending to be a professor and began his journey of procuring radioactive elements from these everyday items until he found something that succeeded in creating fission first he called up a smoke detector company and said he needed 100 smoke detectors for a quote school project not only did they agree to ship him 100 smoke detectors for a low price they told him exactly where the radioactive material was located in the device without ever getting confirmation of his identity or intentions David received the smoke detectors immediately obtained the radioactive material from all of them which was a mercy him too for one by the way welded it all together and placed it inside of a lead casing with a small hole punctured in it creating what is known as a neutron gun the first step to achieving fission still no adults have stepped in to stop this from there keeping in line with David's obsessively focused work ethic and keeping in line with the theme of no adults asking any questions or sounding any alarms whatsoever David was able to extract thorium from thousands of old camping lanterns and get his hands on radium from old luminescent clocks which he purchased from an antique store all that along with some uranium he had ordered from Czechoslovakia over the phone because why the hell wouldn't that be possible and some barium sulfate from the nurses at the local hospitals radiology Ward who just sort of gave it to him David made a makeshift reactor core out of the highly radioactive radium and immerse him he had gotten from the smoke detectors and clocks then he surrounded this radioactive ball with a blanket composed of tiny foil wrapped cubes of thorium ash which he got from the old camping lanterns and uranium powder which were stacked in an alternating pattern with carbon cubes and tenuously held together with duct tape now he had a fully functional an unspeakably dangerous nuclear reactor in his mom's backyard and no one had any idea from there since David was a teenager and really had no business doing any of this and wasn't exactly famous for his safety precautions in the past the level of radioactivity from his reactor kept rising it was already extremely hazardous but David soon realized that he might be putting other people in danger soon he was able to detect the radiation from his reactor five doors down from his mom's house at this point even David decided to dismantle the reactor and try to get all of that radioactive material he created to not be all concentrated in one place so he did what the pros do and started to load it into the trunk of his Pontiac at 2:40 a.m. on August 31st 1994 the police were called by David's neighbors because they thought David was stealing tires from cars he wasn't he was simply loading a nuclear reactor into his own car he told the cops he was just minding his own business basically but they didn't trust him so they searched his car with the fair warning from David that it was quote radioactive this is something the cops didn't like hearing and they assumed David was in possession of an atomic bomb the bomb squad was called in and to the delight of everyone they realized that David didn't have a homemade atomic bomb however they did measure one thousand times the normal background radiation they should have been measuring automatically triggering the federal radiological emergency response plan finally some adults were stepping in kind of it took two months two months for anyone to take any real action when he was initially arrested David didn't say anything about his lab and his mom shed and nobody took a look then when they did take a look two months after David was arrested the NRC didn't actually do anything about cleaning up the shed because it was out of their jurisdiction since it wasn't a federally recognized nuclear site it wasn't until January five months after David was arrested that the EPA showed up to David's potting shed lab what they noted was David's lab quote presented an imminent and substantial endangerment to public health or welfare or the environment and that there was actual or potential exposure to nearby human populations animals or the food chain the memo further stated that conditions such as heavy wind rain or fire could cause the contaminants to migrate or be released and also what they didn't know at that time but what they came to learn later is that during those five months of complete inaction David's mom had thrown away a lot of what was in the shed into just the regular old household trash if you're following David's mom unbeknownst to her put highly radioactive materials things that need to be cleaned up handled sealed and buried by professionals just into the bins thereby spreading the radiation even farther exposing more and more people the EPA's cleanup took place in June they dismantled the potting shed sealed it up in bits and buried it in a dump in the middle of the Great Salt Lake desert where it remains entombed alongside radioactive debris from governmental atomic bomb research and other radioactive industrial waste according to the EPA's official assessment David's nuclear reactor experiments exposed at least 40,000 people to extremely dangerous cancer-causing levels of radiation if there's any sort of lesson to be learned from this it isn't you shouldn't let kids build nuclear reactors in the backyard the lesson is rather sobering and that lesson is that everyone is just kinda winging it when presented with a case like David's none of the grown-ups or government agencies you trust to keep you safe had any idea what to do everything is chaos and we see it again and again right here in America in places like Flint where the water is poisonous or just outside of st. Louis where there is radioactive waste left over from the Manhattan Project in a landfill causing unfathomable illness and death to local residents and basically nothing has been done about it in 1995 the EPA arranged for David to have a full examination to see just what kind of damage all of the radiation he exposed himself to had done but David refused fearful of what he might learn David Hahn died in 2016 when he was 39 of alcohol poisoning which is of course tragic but the real tragedy here is that it seems like all this could have been avoided if some adults just decided to pay attention thanks for watching this video be sure to like this video and subscribe to this channel for more of history's weirdness that you won't find in your textbooks all those textbooks that you had to give back no one has their textbooks anymore right I don't have mine anyway there's this video here is this one here there's more stuff here there's more good stuff if you liked it stick around

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