Steam reforming of methane (CH4) produces "synthesis gas," a mixture of carbon monoxide gas and hydrogen gas, which is the starting point for many important industrial chemical syntheses. An industrial chemist studying this reaction fills 1.5L a flask with of methane gas and 2.6 atm of water vapor at 47C, and when the mixture has come to equilibrium measures the partial pressure of carbon monoxide gas to be 1.4 atm.

Calculate the pressure equilibrium constant for the steam reforming of methane at the final temperature of the mixture. Round your answer to significant digits.

Kp = 4.5

Explanation:

The balanced equation for the production of synthetic gas is

    CH4 +  H20 ⇒ CO + 3H2

Let x be the change in the concentration of each species at equilibrium

 CH4  +   H20   ⇔ CO  +  3H2

Initial                  0.60       2.6        0          0

Change               -x           -x          +x       +3x

Equilibrium      0.60-x      2.6-x       x        3x

Given that the equilibrium partial pressure of H2= 1.4 atm

then, 3x= 1.40

x= 1.4/3 = 0.466667

The equilibrium concentrations are

{CH4} = 0.60- x = 0.60 - 0.466667 = 0.133333atm

{H2O} = 2.60- x = 2.60 - 0.466667 = 2.133333atm

{CO} = x = 0.466667atm

{H2} = 1.4atm (given)

Kp  = {CO}{H2}³

        {CH4}{H2O}

Kp = (0.466667)(1.4)³

         (0.133333)(2.133333)

=  4.501875

Kp = 4.5