## Homework Question 15.23

Junghyuk_Park_1I
Posts: 34
Joined: Wed Sep 21, 2016 2:56 pm

### Homework Question 15.23

After finding the concentration of A via the concentration of B, why is the following step done?

[A]0 - [(2 mol A/1 mol B)*(0.034 mol B/L)]

Rachel Kipp 1I
Posts: 16
Joined: Wed Sep 21, 2016 2:55 pm

### Re: Homework Question 15.23

We use stoichiometry to find our concentration of A. The reaction is 2A$\rightarrow$ B + C

We can find the final concentration of A since we are given the final concentration of B. So, .034mol B/L * (2 mol A/1 mol B)=.068 mol of A.
Since we know our initial amount of A was 0.153 mol, we subtract 0.153 mol A - 0.068 mol A final and get our overall final concentration of A, which is 0.085 mol A/L