[joemok]

thermodynamics gives you the starting point and the end point, but it can't get you from start to finish.  Kinetics gets you from start to finish.

As you have said, thermodynamics can tell us the starting point and end point, but is there relationship with the points with the rate of the equation?

I mean is there possibility that the postulate is luckily right in some cases and in the whole it is wrong? Apart from this, i indeed appreciate the consistence of the postulate's prediction with many reactions.

Actually i am going to take my AL chemistry exams in Hong Kong. In the previous years' past papers, there are quite many questions that set on this. In these questions, there are statements relating thermodynamics and kinetics and they want us to answer: Thermodynamic data provides no kinetic prediction to the reactions.

[english]

I'm no physical chemist, so I don't have an equation handy...sorry 'bout that.

 

[joemok]

I don't if i can quote websites here. but have a look on this:
http://www.science.uwaterloo.ca/~cchieh/cact/c123/chmkntcs.html

In that page, there is a sentence:
"However, thermodynamic data have no direct correlation with reaction rates, for which the kinetic factor is perhaps more important. "

[movies]

I don't if i can quote websites here. but have a look on this:
http://www.science.uwaterloo.ca/~cchieh/cact/c123/chmkntcs.html

In that page, there is a sentence:
"However, thermodynamic data have no direct correlation with reaction rates, for which the kinetic factor is perhaps more important. "

Okay, I think we are really on the same page here, we just don't realize it.

The statement you quoted is completely correct.  The thermodynamic data can't account for kinetic factors.  However, to completely understand a reaction pathway, you need both kinetic and thermodynamic data.  If thermodynamics tell you that a reaction is way uphill (products have higher energy than reactants) then it probably isn't going to happen under normal conditions.  On the other hand, just because a reaction is downhill, it doesn't mean that it will happen.  So kinetics and thermodynamics are separate in the sense that you are looking at different things, but you can't say that they are independent of one another.

The thing that you have to remember is that thermodynamic data don't tell you what the kinetics of a process are, so you have to be very careful about the conclusions you draw from the data you collect.  I think that this is the point of the statement you have quoted.

By definition a postulate isn't proven.  However, the Hammond postulate is consistent with many calculated transition states and loads of thermodynamic data.  Regardless, it doesn't matter whether or not is precisely correct because it does predict the observed behavior.  I think the statement of the Hammond postulate makes logical sense.

[joemok]

I got it! 
thanks for all the repliers, and esp Movies.

[AhmedEzatAlzawalaty]

i learnt that if compound is stable at high temperature is thermodynamically controlled and that stable at low temperature and has a stable structure is formed

[movies]

I got it! 
thanks for all the repliers, and esp Movies.

Phew!  Glad I could help.