In the mixture of NO and CO2 (initially containing 4 mol of NO and 0.9 mole of CO2) reaction occurs according to the equation below: NO(g) + CO2(g) ⇌ NO2(g) + CO(g). At equilibrium 0.1 mol of CO2 was present. What is the equilibrium constant at the temperature of this experiment?

In the mixture of NO and CO2 (initially containing 4 mol of NO and 0.9 mole of CO2) reaction occurs according to the equation below: NO(g) + CO2(g) ⇌ NO2(g) + CO(g). At equilibrium 0.1 mol of CO2 was present. What is the equilibrium constant at the temperature of this experiment?

Explanation

Given reaction:

NO(g) + CO₂(g) ⇌ NO₂(g) + CO(g)

Initial moles:

NO = 4 mol

CO₂ = 0.9 mol

NO₂ = 0

CO = 0

At equilibrium:

CO₂ = 0.1 mol

→ So, change in CO₂ = 0.9 - 0.1 = 0.8 mol consumed

→ Therefore, 0.8 mol of NO also reacted

→ 0.8 mol each of NO₂ and CO formed

Equilibrium moles:

NO = 4 - 0.8 = 3.2 mol

CO₂ = 0.1 mol

NO₂ = 0.8 mol

CO = 0.8 mol

Equilibrium expression:

K = [NO2][CO]/[NO][CO2] = (0.8)(0.8)/(3.2)(0.1) = 0.64/0.32 = 0.2