## 15.19

Vanessa Romero-Campos 2B
Posts: 39
Joined: Fri Sep 25, 2015 3:00 am

### 15.19

Can someone explain how to figure out the rate law of the reaction when you are given a+b+c--> products and a chart of experiments. How do you know what experiments to look at and how do you use them?

Lucian1F
Posts: 87
Joined: Fri Sep 29, 2017 7:07 am
Been upvoted: 1 time

### Re: 15.19

You look for two reactions where there is a difference in concentrations for just one of the reactants, then use this and the change in the rate to get the order of that reactant. Repeat this to get the orders of the others reactants. Once you have all the orders, you can pick any trial you want, plug in all the numbers you know, and solve for k

Ramya Lakkaraju 1B
Posts: 67
Joined: Fri Sep 29, 2017 7:03 am

### Re: 15.19

It is important to choose 2 reactions in which only the concentration of one reactant is changing. This is so that you can say for sure that the change in rate is due to the change in the concentration of that one reactant.

ZoeHahn1J
Posts: 63
Joined: Sat Jul 22, 2017 3:01 am
Been upvoted: 1 time

### Re: 15.19

Choose two experiments (rows) in which all but one reactant has the same concentration and the other changes. Compare the change in the reactant concentration to the change in the rate. If the reactant concentration doubled and the rate doubled, this must be first order for that reactant (ie, if the amount the rate increased = amount the reactant increased). If the reactant concentration doubled and the rate increased by a factor of 4, this is second order (that is, change in reactant conc squared = change in rate). If the reactant concentration changed and the rate didn't change, it's zero order for that reactant.