7.4 Calculating the Equilibrium Constant

01From equilibrium data

Plug equilibrium concentrations into the K expression. If given initial amounts and one equilibrium value, build an ICE table to find the rest.

Kp = Kc(RT)^Δn, where Δn = moles gas products − reactants.

I – initial, C – change (by coefficients), E – equilibrium.

Worked example: H₂ + I₂ ⇌ 2HI, equilibrium 0.1, 0.1, 0.8 M → K = 0.64/0.01 = 64.

Key takeaways

Quick check

1.A ⇌ 2B with [A] = 0.5, [B] = 1.0. K?

2.In an ICE table, the C row follows…

3.Δn for 2SO₂(g) + O₂(g) ⇌ 2SO₃(g)?