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Homework Help: Chem lab help (Rate Laws)

  1. Mar 24, 2014 #1
    1. The problem statement, all variables and given/known data
    Hello. I need help with a lab today that involves rate laws.

    The goal of this lab is to show the concentration of the reactant ions in this equation

    5(HSO3) + 2(IO3) -> I2 + 5(SO4) + H2O + 3H.

    We did several trials of varying amounts of the ions and calculated the rate of disappearance of the bisulfate for each trial.


    I got the rate of disappearance from taking the volume of the bisulfate and dividing it by the time it took (for the blue color to show, this is supposedly an "iodine clock", thus meaning that the bisulfate had all been used up)

    Then I used this formula to calculate the order. I did this for every trial that had the same volume of bisulfate.

    This one is using trials 1 and 2.
    (20 mL/10 mL)^m (10 mL/10 mL)^n = (.85 mL/s /.46 mL/s)

    Sorry if that's hard to read. I did that with trials 1 and 2, 2 and 3, 1 and 3, 1 and 4, and 1 and 5. All the ones that had the same value in my table for the B. That may be confusing. After I did that we averaged the orders of the ones we got. My average order for "m" was 0.95.

    But now I am stumped on what to do next. How do I find the value for the order of N so I can find the Rate Law? Is there a way I can find the value of N if none of them are the same for each of the experiments? I cannot seem to be able to find the N because none of the iodate initial concentrations are the same value from experiment to experiment. Some guidance on what to do next would be helpful.

    2. Relevant equations
    Rate law

    Thank you all for your time, always good help here at physicsforums.
  2. jcsd
  3. Mar 24, 2014 #2
    I figured it out. Just plugged in value of M and did it all for the Ns, the average N came out to be about 3.05.
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