Sulfur trioxide decomposes to form sulfur dioxide and oxygen, like this: 2SO3(g) 2SO2(g) + O2(g) Also, a chemist finds that at a certain temperature the equilibrium mixture of sulfur trioxide, sulfur dioxide, and oxygen has the following composition:

compound	concentration at equilibrium
SO3	1.5M
SO2	0.12M
O2	1.5M

Calculate the value of the equilibrium constant Kc for this reaction. Round your answer to 2 significant digits.