Chapter 10 - Reaction Rates and Chemical Equilibrium - 10.3 Equilibrium Constants - Questions and Problems - Page 383: 10.19

The numerical value of $K_c$ for this reaction is 260

1. Write the equilibrium constant expression: $$K_c = \frac{[Products]}{[Reactants]} = \frac{[ CH_4 ][ H_2O ]}{[ CO ][ H_2 ]^{ 3 }}$$ 2. Substitute the values and calculate the constant value: $$K_c = \frac{( 1.8 )( 2.0 )}{( 0.51 )( 0.30 )^{ 3 }} = 260$$