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Rate law accuracy question?

  1. Apr 1, 2010 #1
    An experiment was done by me to determine the rate law of a reactant. If the reaction occurred faster(ex. by just stirring reactants), would the accuracy of rate law calculated increase? If it doesn't increase accuracy, then what is the point of stirring/swirling the reactants?

    I think that the accuracy would increase, because the rate law is most accurate for the initial concentrations at an specified temperature, and this changes more throughout a longer experiment, than a shorter one. So a faster experimental rate of reaction would increase the accuracy. Need some confirmation. Thanks.
  2. jcsd
  3. Apr 1, 2010 #2
    The rate laws using concentrations assume that the activity of the reactants are approximately equal to their concentrations, which is a fair assumption at low concentrations and temperature.

    Regarding your question about stirring, it might be useful to have the rectants uniformly spread throughout the container.
  4. Apr 1, 2010 #3
    Right, i don't understand why it needs to be uniform.
  5. Apr 1, 2010 #4
    In which situation do you think the reaction A+B->C will proceed faster, given the rate law r=k[A]. Remember that the rate law applies only locally.

    1) A and B uniformly distributed throughout the container.

    2) A on the bottom and B on the top, with smaller region in between where they are mixed.
  6. Apr 1, 2010 #5
    If the concentrations of the reactants vary at different points in the solution, then the reaction rate will also not be the same at all points in the solution.
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