1. The reaction between hydrogen gas and oxygen gas to form water: 2H2 + O2 → 2H2O 2. The reaction between iron and sulfur to form iron sulfide: Fe + S → FeS 3. The reaction between magnesium and oxygen to form magnesium oxide: 2Mg + O2 → 2MgO 4. The reaction between nitrogen gas … Continue reading 10 Examples of combination reactions