A reaction vessel at 27 °C contains a mixture of SO2 (P = 3.10 atm) and O2 (P = 1.10 atm). When a catalyst is added the reaction
2SO2 (g) + O2 (g) ⇌ 2SO3 (g) takes place.
At equilibrium the total pressure is 3.95 atm.
Find the value of Kc. Express your answer using two significant figures.