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At 700 K, the equilibrium constant Kp, for the reaction 2 SO3 (g) ⇌ 2 SO2 (g) + O2 Is 1.8 X 10-3 kPa. What is the numerical value in moles per liter of Kc for the reaction at the same temperature?

Relation between Kp and Kc is given as:
Kp = Kc (RT) ∆n
Kc = Kp / (RT) ∆n
T = 700 K
R = 8.314 J mol -1 K-1
∆n = (2 + 1) – 2 = 1
Kp = 1.8 X 10-3 kPa = 1.8 Pa
Therefore,
Kc = 1.8 Pa / (8.314 J mol -1 K-1) (700)1
= 3.09 X 10-7 mol m-3

Hence, the numerical value in moles per liter of Kc is equal to 3.09 X 10-7 mol m-3