Determine the equilibrium concentrations.

At a particular temperature, k=1.00 x 102 for the reaction.
H2 (g) + F2(g) à2HF

a) In an experiment 2.00 mol of H2 and 2 mol F2 are placed in a 1.00L flask. find out the concentrations of all the species in the flask when equilibrium is reached.

b) To the equilibrium mixture in part a, an additional o.50 mol of H2 is added, what are the new equilibrium concentrations of all species.