8 At 2400 C Ke equals 35 x 103 for the reaction N2g O2g 2NO

8. At 2400 °C, Ke equals 3.5 x 103 for the reaction: N2(g) + O2(g) 2NO(g) Determine whether the following systems are at equilibrium and, if not, in which direction each reaction is expected to proceed: (a) IN2] 0.030 M; [O2] 0.060 M; [NO] 0.020 M (b) [N2] = 0.050 M: [OJ = 0.070 M: [NO] = 3.5 x 10-3 M

Solution

Kc = 3.5 x 10^-3

a)

Qc = [NO]^2 / [N2] [O2]

Qc = (0.020)^2 / 0.03 x 0.06

Qc = 0.222

Qc > Kc . so the reaction proceeds towards reactants side. i.e left

b)

Qc = (3.5 x 10^-3)^2 / 0.05 x 0.07

Qc = 3.5 x10^-3

here Kc = Qc . so there is no shift in the reaction . it is exactly at equilibrium