## Textbook question 7A.17

$aR \to bP, Rate = -\frac{1}{a} \frac{d[R]}{dt} = \frac{1}{b}\frac{d[P]}{dt}$

Paige Lee 1A
Posts: 136
Joined: Sat Sep 07, 2019 12:16 am

### Textbook question 7A.17

For part c, I keep getting 2.85, instead of 2.85*10^-12. But I got the correct answer for part d using 2.85. Is there a typo in the textbook?

The following data were obtained for the reaction A 1 B 1 C S products:
Initial concentration,
[J]initial/(mmol·L21) Initial rate/
Experiment A B C ((mmol)·L21·s21)
1 1.25 1.25 1.25 8.7 2 2.5 1.25 1.25 17.4 3 1.25 3.02 1.25 50.8 4 1.25 3.02 3.75 457
5 3.01 1.00 1.15 ?
(a) Write the rate law for the reaction. (b) What is the order of the reaction? (c) Determine the value of the rate constant. (d) Use the data to predict the reaction rate for Experiment 5.

Rachel Yu 1G
Posts: 113
Joined: Fri Aug 09, 2019 12:15 am

### Re: Textbook question 7A.17

I actually got 2.85 x 10^12 mol/Ls for the rate constant. The only difference is that in the problem, the initial concentration and initial rate are given in mmol/Ls rather than mol/Ls. I think you can get the right answer for part D because the units match up (mmol for both k and concentrations).

Brian J Cheng 1I
Posts: 115
Joined: Thu Jul 11, 2019 12:15 am

### Re: Textbook question 7A.17

That tripped me up too. It's the unit conversions that cause it to have 10^-12.

AKatukota
Posts: 100
Joined: Thu Jul 25, 2019 12:18 am

### Re: Textbook question 7A.17

I believe that they just converted the units differently in the answer key