## Hmwrk 15.39

$\frac{d[R]}{dt}=-k[R]^{2}; \frac{1}{[R]}=kt + \frac{1}{[R]_{0}}; t_{\frac{1}{2}}=\frac{1}{k[R]_{0}}$

Lina Petrossian 1D
Posts: 77
Joined: Fri Oct 05, 2018 12:16 am

### Hmwrk 15.39

15.39 Determine the time required for each of the following second-order reactions to take place: (a) 2 A -> B + C, for
the concentration of A to decrease from 0.10 mol L-1 to
0.080 mol L-1, given that k = 0.015 L mol-1 min-1 for the rate law expressed in terms of the loss of A; (b) A -> 2 B + C, when [A]0 = 0.15 mol L-1, for the concentration of B to increase to 0.19 mol L-1, given that k = 0.0035 L mol-1 min-1 in the rate law for the loss of A.

What is the purpose of writing "in the rate law for the loss of A"? What else could have been written and how would that effect how we solved the problem?

Danny Zhang 4L
Posts: 62
Joined: Fri Sep 28, 2018 12:26 am

### Re: Hmwrk 15.39

To my understanding, the question could have just told us that "k = 0.015 L mol-1 min-1 for the rate law of this reaction", and that would not change how you should approach the problem.