Answer
a) $8.2\times10^{-2}$
b) 0.29
Work Step by Step
a) $K_{c} = \frac{[NH_{3}]^{2}}{[N_{2}][H_{2}]^{3}} = \frac{(0.25)^{2}}{0.11(1.91)^{3}} \approx 8.2\times10^{-2}$
b) The equation is divided by 2. So, the new equilibrium constant is the square root of the original. i.e. $K_{c}= (8.2\times10^{-2})^{\frac{1}{2}} \approx 0.29$
