Determine the value of K for the reaction, 2 NOCl(g) <=> O2(g) + N2(g) + Cl2(g)

Question

by combining the equations below to give the needed equation and using their K values to calculate the K value of that equation.

1/2 N₂(g) + 1/2 O₂(g) <=> NO(g)         K = 0.0112

NO(g) + 1/2 Cl₂(g) <=> NOCl(g)    K = 0.0478

Answer 1

Hess' Law: 2NOCl <==> O2 + N2 + Cl2 ... K = ? TARGET EQUATION

eq. 1: 1/2 N2 + 1/2 O2 <==> NO ... K = 0.0112

eq. 2: NO + 1/2 Cl2 <==> NOCl ... K = 0.0478

Reverse eq. 2 and multiply by 2 to get 2NOCl on left and change sign of K:

2NOCl <==> 2NO + Cl2 ... K = -0.0956

Reverse eq. 1 and multiply by 2 and change sign:

2NO <==> N2 + O2 ... K = -0.0224

Add the two new equations:

2NOCl <==> Cl2 + N2 +O2 ... K = -0.0956 + -0.0224

K = 0.118