Question

Determine the equilibrium constant, Kc, for the following reaction: N2(g) + O2(g) ⇌ 2NO(g) If the initial concentration of N2 is 0.50 M, O2 is 0.40 M, and NO is 0.10 M at equilibrium, what is the value of Kc?

Answer 1

To determine the equilibrium constant Kc, we first need to find the change in concentration for each species during the reaction. We can do this by setting up an ICE  Initial, Change, Equilibrium  table:``          N2 g    O2 g    2NO g Initial:  0.50    0.40    0.00Change:  -x       -x      +2xEquilibrium: 0.50-x  0.40-x  0.10+2x``We are given the equilibrium concentrations of N2, O2, and NO. We can use these values to solve for x:0.50 - x = 0.50  no change in N2 concentration x = 00.40 - x = 0.40  no change in O2 concentration x = 00.10 + 2x = 0.10  equilibrium concentration of NO 2x = 0x = 0Since there is no change in the concentrations of the reactants and products, the reaction has not proceeded. Therefore, the equilibrium constant Kc is 1, as the reaction is at equilibrium with no change in concentrations:Kc = [NO]^2 /  [N2] * [O2] Kc =  0.10 ^2 /  0.50 * 0.40 Kc = 0.01 / 0.20Kc = 0.05The equilibrium constant Kc for the given reaction is 0.05.