For 2 so2g o2g 2 so3g kp 30 104 at 700 k in a 200-l

Question

At 800 K the equilibrium constant for I2(g) 2 I(g) is Kc = 3.1 10-5. If an equilibrium mixture in a 10.0-L vessel contains 3.18 10-2 g of I(g), how many grams of I2 are in the mixture?

For 2 SO2(g) + O2(g) 2 SO3(g), Kp = 3.0 104 at 700 K. In a 2.00-L vessel the equilibrium mixture contains 1.72 g of SO3 and 0.171 g of O2. How many grams of SO2 are in the vessel?