Page **1** of **1**

### 15.19a

Posted: **Tue Mar 06, 2018 1:55 am**

by **Abigail Urbina 1K**

Can someone explain to me how they found the order of reactant B? I know to look at experiments 2 and 3 to solve this. I'm just confused because the solutions manual says that increasing the concentration of B by the ratio 3.02/1.25 increases the rate by (3.02/1.25)^2, so the reaction is then second order. I'm not really sure how they came up with that logic. Could someone clarify?

### Re: 15.19a

Posted: **Tue Mar 06, 2018 2:54 am**

by **Silvino Jimenez 1A**

I believe they made a very generous estimation and rounded the increase in rate between experiments 2 and 3. The change in [B] increased from 1.25 to 3.02 which is approx an increase of a multiple of 2. The change in the concentration is approx. an increase of a multiple of 3. Here is where I was confused too.

Here I am assuming they rounded the increase i concentration rate to a multiple of 4. This would allow us to conclude that the concentartion was squared thus making it a second order reaction

### Re: 15.19a

Posted: **Tue Mar 06, 2018 10:20 am**

by **Alvin Tran 2E**

To find the order of [B] you want to compare reaction 1 and 3 because the concentrations of A and C stay the same.

So we have

5.84 = 2.416

^{M}Solve for M and you get 2.

So B is second order.