### 15.17 type problems

Posted:

**Thu Mar 08, 2018 2:23 pm**How much work do we need to show for this kind of problem? Because sometimes you can just look at the data and estimate the orders for the reactants.

Created by Dr. Laurence Lavelle

https://lavelle.chem.ucla.edu/forum/

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=145&t=29223

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Posted: **Thu Mar 08, 2018 2:23 pm**

How much work do we need to show for this kind of problem? Because sometimes you can just look at the data and estimate the orders for the reactants.

Posted: **Thu Mar 08, 2018 4:06 pm**

Yes you can look at the data and tell the order of the reactant but Dr.Lavelle requires some sort of work or explanation in order to receive full credit. You can use the ratio of concentration to rate to show work.

Posted: **Thu Mar 08, 2018 4:12 pm**

For work, I usually show something like 2^a=2 (the concentration doubled, rate doubled), therefore a=1, and the order of [A] is first order. But you need to show work, at least on the quizzes and tests,

Posted: **Thu Mar 08, 2018 5:39 pm**

You can show your work by writing the ratio of concentration in exp 1 over concentration in exp 2 raised to some power equals the ratio of rate in exp 1 over rate in exp 2. This would be written as (conc1/conc2)^n=(rate1/rate2) where n is the order.

Posted: **Thu Mar 08, 2018 6:14 pm**

I show work in these problems by:

1) Specifying which reactant I'm finding the order of

2) Taking the ratio of the initial rates for the two experiments

3) Taking the ratio of the concentrations for the two experiments

4) Solve for n in: (ratio of concentrations)^n=(ratio of initial rates)

5) The value of n is the order for that reactant

1) Specifying which reactant I'm finding the order of

2) Taking the ratio of the initial rates for the two experiments

3) Taking the ratio of the concentrations for the two experiments

4) Solve for n in: (ratio of concentrations)^n=(ratio of initial rates)

5) The value of n is the order for that reactant