Chemistry (7th Edition)

(a) $K_c = 7.9 \times 10^4$ (b) $K{_c} ' = 1.3 \times 10^{-5}$
** Remember to put the balanced coefficients as the exponents of the concentrations. (a) $K_c = \frac{[Products]}{[Reactants]} = \frac{(5.0 \times 10^{-2})^2}{(3.0 \times 10^{-3})^2(3.5 \times 10^{-3})} = 7.9 \times 10^4$ (b) $K{_c} '= \frac{[Products]}{[Reactants]} = \frac{(3.0 \times 10^{-3})^2(3.5 \times 10^{-3})}{(5.0 \times 10^{-2})^2} = 1.3 \times 10^{-5}$