Basic Chemistry questions
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One often knows that a triple bond between 2 carbon atoms is NOT 3 times as strong as a single bond between 2 carbon atoms. However I do not understand the explanation behind this.
Another question is regarding stirring. Take for example a reaction between NaOH and HCl acid. When NaOH is added to acid, we would often be required to stir the mixture. May I know what are other purposes of stirring beside making the NaOH solution be even distributed throughout mixture? If I do not remember wrongly, stirring does help hasten the reaction time, doesn't it? (Not sure about this, Haha)
A physics-chemistry question: does an insulated container prevent solution inside it from absorbing and giving off heat energy to surroundings?
Very simple questions which I need some addressing.
Not forgetting, thanks.
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>>> One often knows that a triple bond between 2 carbon atoms is NOT 3 times as strong as a single bond between 2 carbon atoms. However I do not understand the explanation behind this. <<<
To properly, fully, correctly understand this, you need to get into 'A' level concepts. It has to do with atomic radii, electronegativity, bond polarity, electron repulsion between lone pairs, etc.
Here's a further hint : even the (seemingly) same single bond between two atoms of the same element (eg. C-C) has different bond strengths/enthalpies in different molecules (different microenvironments), let alone single bonds between different element atoms in different molecules (eg. C-H vs H-H vs O-H, etc)!
So obviously, since two different single bonds (eg. C-H vs H-H) already have different strengths, you cannot possibly have a simplified direct relationship between ALL triple bonds to ALL single bonds (because different single bonds already have different strengths among themselves!).
Here's a sneak preview into the Data Booklet used at 'A' levels (which is the average bond energies across a range of commonly encountered molecules) :
>>> Another question is regarding stirring. Take for example a reaction between NaOH and HCl acid. When NaOH is added to acid, we would often be required to stir the mixture. May I know what are other purposes of stirring beside making the NaOH solution be even distributed throughout mixture? If I do not remember wrongly, stirring does help hasten the reaction time, doesn't it? (Not sure about this, Haha) <<<
One reason why stirring hastens reaction time, is because the OH-(aq) becomes more evenly distributed by your stirring (and hence more available by virtue of allowed closer proximity for reaction with the more evenly spread out or ubiquitous H+ from the acid), in addition to (obviously) increasing kinetic energy of all particles (solute, solvent, reactant, products) by your stirring. You gotta make links and see connections between everything (eg. between Chemistry and Biology, between Chemistry and Physics, between Science, Philosophy, Religion, etc). Then the universe will actually begin to make sense.
Also, don't forget the even distribution of heat is also a reason for stirring (particularly when heating is involved. Besides, almost all reactions are at least slightly endothermic or exothermic.)
>>> A physics-chemistry question: does an insulated container prevent solution inside it from absorbing and giving off heat energy to surroundings? <<<
For your answer (spoonfeeding's no fun), here's another glimpse into 'A' level Chemistry (and Physics) :
http://en.wikipedia.org/wiki/Calorimeter
Originally posted by anpanman:One often knows that a triple bond between 2 carbon atoms is NOT 3 times as strong as a single bond between 2 carbon atoms. However I do not understand the explanation behind this.
Another question is regarding stirring. Take for example a reaction between NaOH and HCl acid. When NaOH is added to acid, we would often be required to stir the mixture. May I know what are other purposes of stirring beside making the NaOH solution be even distributed throughout mixture? If I do not remember wrongly, stirring does help hasten the reaction time, doesn't it? (Not sure about this, Haha)
A physics-chemistry question: does an insulated container prevent solution inside it from absorbing and giving off heat energy to surroundings?
Very simple questions which I need some addressing.
Not forgetting, thanks.
-
Originally posted by anpanman:
One often knows that a triple bond between 2 carbon atoms is NOT 3 times as strong as a single bond between 2 carbon atoms. However I do not understand the explanation behind this.
Another question is regarding stirring. Take for example a reaction between NaOH and HCl acid. When NaOH is added to acid, we would often be required to stir the mixture. May I know what are other purposes of stirring beside making the NaOH solution be even distributed throughout mixture? If I do not remember wrongly, stirring does help hasten the reaction time, doesn't it? (Not sure about this, Haha)
A physics-chemistry question: does an insulated container prevent solution inside it from absorbing and giving off heat energy to surroundings?
Very simple questions which I need some addressing.
Not forgetting, thanks.
This is hardly a "basic" question at your level.
To understand why the bonds are not equal in strength, you must first look up how the electrons orbit around the nucleus.
Google is your best friend!
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Originally posted by 16/f/lonely:
This is hardly a "basic" question at your level.
To understand why the bonds are not equal in strength, you must first look up how the electrons orbit around the nucleus.
Google is your best friend!
I onli know one thing
R=V/I
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another way to look at your first question is that after the first bond has been formed, the system in question has already changed.
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Originally posted by anpanman:
One often knows that a triple bond between 2 carbon atoms is NOT 3 times as strong as a single bond between 2 carbon atoms. However I do not understand the explanation behind this.
>>> One often knows that a triple bond between 2 carbon atoms is NOT 3 times as strong as a single bond between 2 carbon atoms. However I do not understand the explanation behind this. <<<
This one's written for you, anpanman! I didn't forsake you!
http://www.sgforums.com/forums/2297/topics/320107?page=4#posts-8799724
(scroll down to the bottom after clicking link above)