Advertisement
If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)
Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie
Hi there,
There is an issue with role permissions that is being worked on at the moment.
If you are having trouble with access or permissions on regional forums please post here to get access: https://www.boards.ie/discussion/2058365403/you-do-not-have-permission-for-that#latest

GAMSAT sample paper Unit 9 help

  • 28-08-2011 9:07am
    #1
    Registered Users, Registered Users 2 Posts: 132 ✭✭


    the conversion of sucrose to fuctose and glucose in acid ic solution can be represented by the following eqn

    Sucrose(aq) + H20 (H+ above arrow)-> fructose(aq) + Glucose

    Rate law for rxn is rate =k(H+)(sucrose)

    let the rate f the reaction at pH 3 be r .If all the variable are kept constant except that pH is changed to 2 then the rate will be ??

    so does that mean

    r=k(3)(Sucrose)
    r/3=k(sucrose)
    ?? but whats the story with the ph change of 2?:confused:


Comments

  • Closed Accounts Posts: 1,141 ✭✭✭imported_guy


    the conversion of sucrose to fuctose and glucose in acid ic solution can be represented by the following eqn

    Sucrose(aq) + H20 (H+ above arrow)-> fructose(aq) + Glucose

    Rate law for rxn is rate =k(H+)(sucrose)

    let the rate f the reaction at pH 3 be r .If all the variable are kept constant except that pH is changed to 2 then the rate will be ??

    so does that mean

    r=k(3)(Sucrose)
    r/3=k(sucrose)
    ?? but whats the story with the ph change of 2?:confused:

    you should really be posting these in the relevant chemistry/physics forums you will get a much better response


  • Registered Users, Registered Users 2 Posts: 1,979 ✭✭✭Jammyc


    pH 2 is ten times as acidic as pH3 and 100 times as acidic as pH4.

    Seeing as the rate is dependant on the H+ concentration, a pH change from 3 to 2 would bring a 10 fold increase in the H+ conc.

    Not sure what the answer would be but thats what I can see in it.


  • Registered Users, Registered Users 2 Posts: 1 Kbear


    pH = -log[H+]

    A pH 3 = 0.001 M H+
    A pH 2 = 0.01 M H+
    Therefore, at a pH of 2 the concentration of hydrogen ions is 10 times greater than at a pH of 3

    Answer= 10r


  • Registered Users, Registered Users 2 Posts: 132 ✭✭spotsanddots


    your right the answer is 10 times the rate 10r


Advertisement