## 11.39

Grace Boyd 2F
Posts: 50
Joined: Thu Jul 27, 2017 3:01 am

### 11.39

"Use the information in table 11.2 to determine the value of K at 500 K for the reaction 2 BrCl(g) + H2(g) = Br2(g) + 2 HCl (g) "
The equations given in table 11.2 are:
2 BrCl(g) = Br2(g) + Cl2(g) K=377
H2(g) + Cl2(g) = 2HCl(g). K=4.0x10^31

I am wondering why in the solutions it says that since these 2 equations are added together to get the equation given in question 39, the two K values are multiplied to find the new value of K. Why do we multiply these K values?
Last edited by Grace Boyd 2F on Sun Nov 26, 2017 9:30 pm, edited 1 time in total.

Aijun Zhang 1D
Posts: 53
Joined: Tue Oct 10, 2017 7:13 am

### Re: 11.39

The Kc for 2BrCl + H2 = Br2 + 2HCl (you wrote Br2 instead of H2 which is wrong) is expressed as [Br2]*[HCl]^2/([H2][BrCl]^2).
The Kc for 2BrCl=Br2 + Cl2 is expressed as [Br2][Cl2]/[BrCl]^2; the Kc for H2 + Cl2 = 2HCl is expressed as [HCl]^2/([H2][Cl2]). As the Kcs of later two times, you can get the expression of Kc for the reaction it asks. So the two Kc value should be timed.

Grace Boyd 2F
Posts: 50
Joined: Thu Jul 27, 2017 3:01 am