## Chemistry 9th Edition

K = $6.9\times10^{-4}$
According to the law of mass action, a general formula of the form jA + kB ⇌ lC + mD is represented by the following equilibrium expression: K = $\frac{[C]^{l}[D]^{m}}{[A]^{j}[B]^{k}}$ where A, B, C, and D represent the chemical species and j, k, l, and m are their coefficients in the balanced equation. Therefore, K = $\frac{[NO]^{2}}{[N_{2}][O_{2}]}$ K = $\frac{(4.7\times10^{-4})^{2}}{(4.1\times10^{-2})(7.8\times10^{-3})}$ K = $6.91\times10^{-4}$ (carried one extra significant digit) K = $6.9\times10^{-4}$