A mixture of 2.5 moles of H2O and 100 g of C are placed in a 50.0 L container and
allowed to come to equilibrium in the following reaction:
C(s) + H2O(g) CO(g) + H2(g)
The equilibrium concentration of hydrogen gas is found to be 0.040 M. What is the
equilibrium concentration of the water vapour?