Question

Write the equilibrium constant expressions for K_c for the following reactions: 2NO_2(g)+7H_2(g) equivalent 2NH_3(g)+4H_2O(l) 2ZnS(s)+3O_2(g) equivalent 2ZnO(s)+2SO_2(g) C(s)+CO_S(g) equivalent 2CO(g) C_6H_5COOH(aq) equivalent C_6H_5COO^-(aq)+H^+(aq)

Answer 1

aA+bB⇌cC+dDaA+bB⇌cC+dD

The equilibrium constant always has the same value, irrespective of the amounts of A, B, C and D you started with. It is also unaffected by a change in pressure or whether or not you are using a catalyst.

The square brackets show concentatons in mol dm-3 equilibrium constant C[AB) Right-hand side of the equaton on top; left-hand side on the bottom "C" shows that it is in terms of concentation The indices are the numbers in front of each substance in the chemical equation.

Compare this with the chemical equation for the equilibrium. The convention is that the substances on the right-hand side of the equation are written at the top of the Kc expression, and those on the left-hand side at the bottom. The indices (the powers that you have to raise the concentrations to - for example, squared or cubed or whatever) are just the numbers that appear in the equation.

2NO2(g) + 7H2(g) ←→ 2NH3(g) + 4H20(1) a. [NH3]? H2o INO21 [H21 b. 2ZnS(s) 302g)2Zno(s) 2SO2(g) IZnop2 so22 Zns1 1o213 C(s) + CO2(g) (-) 2CO(g) C. CO] Kc= ICI ICO2 Kc = C6H5COOH