Sulfur trioxide is manufactured in the Contact process by the reversible reaction between sulfur dioxide, SO2\text{SO}_2SO2, and oxygen, O2\text{O}_2O2.
Write the balanced symbol equation for this reversible reaction to produce sulfur trioxide, SO3\text{SO}_3SO3.
30 exam-style questions on Edexcel GCSE Chemistry 6.3 Dynamic equilibria, covering 6.3.1 The Haber process as a reversible reaction, 6.3.2 Conditions and rate in industrial equilibria, and 6.3.3 Fertilisers and the preparation of ammonium sulfate. Each one has a worked solution and a mark scheme showing where the marks go.