Hydrogen can be produced by steam-cracking methane according to
the reaction:

CH4 + 2 H2O ⟺ CO2 + 4 H2

An initial mixture at 10-atm total pressure and 700K consists of
50% excess steam. Determine the following: (a) the equilibrium
constant for the conversion (b) the equilibrium mole fractions of
CH4, H2O, CO2, and H2

Gibbs (CH4) @ 298K = -50.8 kJ/mol

Gibbs (CO2) @ 298K = -394.42 kJ/mol

Gibbs (H2) @ 298K = 0

Gibbs (H2O) @ 298K = -228.6 kJ/mol