At equilibrium the concentrations of hydrofluoride gas

Question

Question 1:

2 HF(g) <--> H₂(g) + F_2(g) 

At equilibrium, the concentrations of hydrofluoride gas, fluorine gas and hydrogen gas are (9.0000x10^-1) mol/L, (4.10x10^0) mol/L and (9.0000x10^-1) mol/L respectively. What is the value of the equilibrium constant? Answer to 3 Significant digits

Question 2:

The following system was set up and allowed to come to equilibrium:

C2H2(g) + 2 H2(g) <--> C2H6(g) 

At equilibrium the concentration of ethyne was (4.1750x10^0) mol/L, the concentration of hydrogen gas was (4.99x10^0) mol/L. The value of the equilbrium constant for the reaction at that temperature is (6.3678x10^2). What was the concentration of the ethane? (Answer to 3 S.D.)

Note: Your answer is assumed to be reduced to the highest power possible.

Question 3:

At equilbrium, the following system had a concentration of sulfur dioxide gas of 0.200 mol/L, a concentration of sulfur trioxide gas of 0.250 mol/L and a concentration of oxygen gas of 0.300 mol/L. In a second flask a new amount of reach of the substances was combined and an equilibrium was established. In the new equilibrium the concentration of the sulfur dioxide gas is 0.100 mol/L and the concentration of the oxygen gas is 2.35 mol/L. What is the new concentration of the sulfur trioxide gas?

2 SO₂(g) + O₂(g) <--> 2 SO₃(g) 

A-0.350 mol/L

B-0.122 mol/L

C-0.659 mol/L

D-0.979 mol/L