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# Kinetics- the effect of decreasing temperature on most probable energy watch

1. Hi,

I was doing some past paper questions on kinetics when I came across a question from June 2011 CHEM2 (http://filestore.aqa.org.uk/subjects...W-QP-JUN11.PDF.) Question 1Cii of the paper asks
"State how, if at all, the number of molecules with the most probable energy (Emp)changes as the temperature is decreased without changing the total number ofmolecules"

I would have assumed that by decreasing the temperature, you shift the graph to the left, thus reducing the number of molecules with the most probable energy from the original graph. However, when I looked at the markscheme, it states that the number of moecules with most probable energy actually increases as you decrease temperature.

How could this be?
2. (Original post by z4_)
Hi,

I was doing some past paper questions on kinetics when I came across a question from June 2011 CHEM2 (http://filestore.aqa.org.uk/subjects...W-QP-JUN11.PDF.) Question 1Cii of the paper asks
"State how, if at all, the number of molecules with the most probable energy (Emp)changes as the temperature is decreased without changing the total number ofmolecules"

I would have assumed that by decreasing the temperature, you shift the graph to the left, thus reducing the number of molecules with the most probable energy from the original graph. However, when I looked at the markscheme, it states that the number of moecules with most probable energy actually increases as you decrease temperature.

How could this be?
Sorry I did not read the question carefully enough.

The curve gets flatter and longer as the temperature increases. Hence the number of particles with the mean energy decreases as the temperature increases.

3. (Original post by charco)
it's wrong, you are correct.

PM'd You
4. The mark scheme is right, if you decrease the temperature the number of molecules with the EMP increases as the peak of the graph gets higher, distribution is less. If you look up temperature change of Maxwell boltzmann distribution graphs you'll see if you decrease the temp, the EMP increases

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