## 15.23 c

$\frac{d[R]}{dt}=-k[R]; \ln [R]=-kt + \ln [R]_{0}; t_{\frac{1}{2}}=\frac{0.693}{k}$

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Gabriela Carrillo 1B
Posts: 53
Joined: Fri Sep 29, 2017 7:04 am

### 15.23 c

If given the molarity of how much product was formed, how would you use dimensional analysis to figure out [A]?

Ashin_Jose_1H
Posts: 51
Joined: Fri Sep 29, 2017 7:04 am

### Re: 15.23 c

We know that two moles of A are consumed to produce 1 mole of B. Therefore, we can calculate the resulting concentration by multiplying the concentration of B by two. Since we are given the initial concentration of A, the concentration of A at time t, would be the initial concentration minus the resulting concentration we calculated.

Yutian Zhao -1J
Posts: 30
Joined: Fri Sep 29, 2017 7:05 am

### Re: 15.23 c

according to unique reaction rate law: -(1/a)*delta[A]/delta t= (1/b)*delta[B]/delta t, we can cancel delta t on both sides since they are the same, then we know that a=2, b=1, and we also know delta[B] =0.034mol/L since [B]initial is zero. Then we can derive delta[A] from the equation. since we also know the initial [A] is 0.153mol/L, we can use initial[A]- delta[A] to get [A] at 115s. Hope it helps.

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