Example Question - 3

AQA AS-level ChemistryEquilibriaLesson 16 of 20

Question: 0.400 mol of SO₂ and 0.200 mol of O₂ were placed in a 2.00 dm³ vessel. At equilibrium, 0.300 mol of SO₃ had formed. Calculate K_c and give its units.
2SO₂(g) + O₂(g) ⇌ 2SO₃(g)

Step 1: equilibrium moles. Forming 0.300 mol of SO₃ uses 0.300 mol of SO₂ and 0.150 mol of O₂. SO₂ left = 0.100 mol and O₂ left = 0.050 mol.

More in Equilibria

• The Equilibrium Constant Kc
• Finding the Value of Kc
• Example Question - 1
• Example Question - 2
• The Effect of Changing Temperature on Kc
• The Effect of Changing Concentration on the Position of Equilibrium
• Kc and the Position of Equilibrium
• Catalysts

All 20 lessons in Equilibria · All AQA AS-level Chemistry topics