Calculate Kc at this temperature for the following reaction:

Question

The equilibrium constant, K_c , for the following reaction is 10.1 at 352 K.

CH₂Cl₂ (g) --> CH₄ (g) + CCl₄ (g)

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Calculate K_c  at this temperature for the following reaction:

 K_c = 1/2 CH₄ (g) + 1/2 CCl₄ (g) --> CH₂Cl₂ (g)

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Answer 1

I believe you presented an incorrect equation and I think it should have a 2 in front of CH2Cl2 as....

2CH₂Cl₂ (g) <==> CH₄ (g) + CCl₄ (g) Kc1 = 10.1

1/2 CH₄ (g) + 1/2 CCl₄ (g) <==> CH₂Cl₂ (g) Kc2 = ?

Since the 2nd reaction is the reverse of the first reaction, the Kc will be the inverse of the Kc for reaction 1. But the 2nd reaction is ALSO 1/2 the original, so the Kc would be the square root of that for reaction 1. Putting these together, the Kc for the 2nd reaction would be √1/Kc1

√ 1/10.1 = Kc2

Kc2 = 0.3115