Hey there! Sign in to join this conversationNew here? Join for free

Kinetics- the effect of decreasing temperature on most probable energy Watch

    • Thread Starter
    Offline

    0
    ReputationRep:
    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?
    Thanks in advance
    • Community Assistant
    • Study Helper
    Offline

    14
    ReputationRep:
    Community Assistant
    Study Helper
    (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?
    Thanks in advance
    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.

    Name:  MB2.gif
Views: 57
Size:  8.3 KB
    Offline

    2
    ReputationRep:
    (Original post by charco)
    it's wrong, you are correct.

    PM'd You
    Offline

    4
    ReputationRep:
    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
 
 
 
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • Poll
    Brussels sprouts
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

    Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

    Quick reply
    Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.