Chapter 10 - Reaction Rates and Chemical Equilibrium - 10.4 Using Equilibrium Constants - Questions and Problems - Page 386: 10.28

$$[NH_3] = 0.14 \space M$$

1. Write the equilibrium constant expression: $$K_c = \frac{[Products]}{[Reactants]} = \frac{[ NH_3 ]^{ 2 }}{[ H_2 ]^{ 3 }[ N_2 ]}$$ 2. Solve for the missing concentration: $$ \sqrt[2]{K_c \times [ H_2 ]^{ 3 }[ N_2 ]}{} = [NH_3]$$ 3. Evaluate the expression: $$ [NH_3] = \sqrt[2]{(1.7 \times 10^2 ) \times {( 0.18 )^{ 3 }( 0.020 )}{}}$$ $$[NH_3] = 0.14 \space M$$