Question

At room temperature (25 °C), the gas ClNO is impure because it decomposes slightly according to the equation

2ClNO(g) Cl2(g) + 2NO(g)

The extent of decomposition is about 4%. Based upon this, what is the approximate value of ΔG°298 for the reaction at that temperature?

Is my answer correct?:
Kp = (0,02* 0.04^2)/ (0.96^2)= 3.472E5

ΔG°298 = [-(8.314)*298*In(3.472E5)]1000J
ΔG°298 = 25.4J

Answer 1

I think the sign for exponent of Kp is -5 and not +5. Check that out.
I think you have too many significant figures in 3.472 but you have rounded correctly in the answer. .

I don't understand the dG calculation at all. If I plug in 3.472E+5 I don't get 25.4. If I plug in 3.472E-5 (Kp that should be used) I get 25.4 kJ and not 25.4 J.