Hey there! Sign in to join this conversationNew here? Join for free
    • Thread Starter
    Offline

    0
    ReputationRep:
    Hi,I've been doing the Iodine-Clock Reaction for my Salters investigation, using Potassium Iodide, Sodium Thiosulphate and persuklfate, I know the order of the reaction is rate=k[I-][S2O82-] , so they're both first order.

    But how do I find the rate constant k?

    I kept the conc of one substance constant for one experiment, then changed the other and vice versa, I have all the times/rates I just have no clue how to do it.

    Thanks,

    Ben Ingham
    Offline

    0
    ReputationRep:
    (Original post by Ben Ingham)
    Hi,I've been doing the Iodine-Clock Reaction for my Salters investigation, using Potassium Iodide, Sodium Thiosulphate and persuklfate, I know the order of the reaction is rate=k[I-][S2O82-] , so they're both first order.

    But how do I find the rate constant k?

    I kept the conc of one substance constant for one experiment, then changed the other and vice versa, I have all the times/rates I just have no clue how to do it.

    Thanks,

    Ben Ingham
    You have the equation, simply rearrange:

    k = rate/[I-][S2082-]

    Using the corresponding rates and concentrations.
    The answer should be similar no matter which set of results you use, assuming you're performed the procedure correctly.
    • Thread Starter
    Offline

    0
    ReputationRep:
    (Original post by Cyclohexane)
    You have the equation, simply rearrange:

    k = rate/[I-][S2082-]

    Using the corresponding rates and concentrations.
    The answer should be similar no matter which set of results you use, assuming you're performed the procedure correctly.


    The problem I have is that I don't know which values to use for [I-] and [S2O82-, I did two experiments keeping one conc. constant and varying the other, so do I use 1 for the constant value and the concentration of the other to work it out?
    Offline

    0
    ReputationRep:
    (Original post by Ben Ingham)
    The problem I have is that I don't know which values to use for [I-] and [S2O82-, I did two experiments keeping one conc. constant and varying the other, so do I use 1 for the constant value and the concentration of the other to work it out?
    It shouldn't matter, the rate constant should be the same/similar whichever set of results you use.
    If you're unsure, calculate the rate constant using a few different sets of data, to see whether they're similar.


    Posted from TSR Mobile
 
 
 
  • 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
    Would you like to hibernate through the winter months?
  • 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.