sulfur trioxide gas dissociates into sulfer dioxide gas and oxygen gas at 1250 degrees C. In an experiment, 3.6 moles of sulfur trioxide were placed into an evacuated 3.0-L flask. THe concentration of sulfur dioxide gas measured at equilibrium was found to be 0.20 M. What is the equilibrium constant, Kc, for the reaction?

Question

SO3 ==> SO2 + O2
(SO3) = 3.6 mols/3.0 L = 1.2 M initially.
(SO2) = 0.2 M at equilibrium.
(O2) = 0.2 M at equilibrium.
(SO3) = 1.2-0.2 = 1.0 M
Plug into Kc and calculate.

Answer 1

1.6 x 10^-2