Answer
(a) $$K_c = \frac{[ N_2 ][ H_2O ]^{ 2 }}{[ NO ]^{ 2 }[ H_2 ]^{ 2 }}$$
(b) $K_c = 720 = 7.2 \times 10^2$
Work Step by Step
1. Write the equilibrium constant expression:
- The exponent of each concentration is equal to its balance coefficient.
$$K_c = \frac{[Products]}{[Reactants]} = \frac{[ N_2 ][ H_2O ]^{ 2 }}{[ NO ]^{ 2 }[ H_2 ]^{ 2 }}$$
2. Substitute the values and calculate the constant value:
$$K_c = \frac{( 0.082 )( 4.64 )^{ 2 }}{( 0.31 )^{ 2 }( 0.16 )^{ 2 }} = 720$$
