Phosphorus, sulfur and chlorine can all react with oxygen to form oxides.

1. (a)(i)Phosphorus reacts with an excess of oxygen to form phosphorus(V) oxide. Write an equation to show the reaction of phosphorus with excess oxygen.[1]
2. (a)(ii)Describe the reaction of phosphorus(V) oxide with water.[2]
3. (a)(iii)State the structure and bonding of solid phosphorus(V) oxide.[1]
4. (b)(i)The two most common oxides of sulfur are SO2 and SO3. When SO₂ dissolves in water, a small proportion of it reacts with water to form a weak Brønsted-Lowry acid. Explain the meaning of the term weak Brønsted-Lowry acid.[2]
5. (b)(ii)Write the equation for the reaction of SO2 with water.[1]
6. (b)(iii)SO2 reacts with NO2 in the atmosphere to form SO3 and NO. NO is then oxidised in air to form NO2. SO2 + NO2 → SO3 + NO; 2NO + O2 → 2NO2; State the role of NO2 in this two-stage process.[1]
7. (c)(i)Emissions of SO2 from coal-fired power stations can be reduced by mixing the coal with powdered limestone. Limestone is heated to form CaO in reaction 1. This then reacts with SO2 and O₂ to form CaSO4 in reaction 2. reaction 1: CaCO3(s) → CaO(s) + CO₂(s); reaction 2: CaO(s) + SO2(g) + ½O2(g) → CaSO4(s); State the type of reaction occurring in reaction 1.[1]
8. (c)(ii)Use the data to calculate the enthalpy change of reaction 2. compound | ΔH/kJ mol⁻¹ ---|--- CaO(s) | -635 SO2(g) | -297 CaSO4(s) | -1434 enthalpy change of reaction 2 = ................................... kJ mol⁻¹[2]
9. (d)(i)Chlorine forms several oxides, including Cl₂O, ClO2 and Cl₂O6. Draw a 'dot-and-cross' diagram of Cl₂O. Show outer-shell electrons only.[1]
10. (d)(ii)ClO2 can be prepared by reacting NaClO2 with Cl2. Write the oxidation state of chlorine in each species in the boxes provided. 2NaClO2 + Cl2 → 2ClO2 + 2NaCl; oxidation state of chlorine: [+3] [ ] [ ] [ ][1]
11. (d)(iii)Cl₂O6(g) is produced by the reaction of ClO2(g) with O3(g). 2ClO2(g) + 2O3(g) ⇌ Cl₂O6(g) + 2O2(g) ΔH = −216 kJ mol⁻¹. The reaction takes place at 500K and 100kPa. State and explain the effect on the yield of Cl₂O6(g) when the experiment is carried out: • at 1000K and 100 kPa • at 500 K and 500 kPa.[4]
12. (e)(i)Element E is a Period 5 element. E reacts with oxygen to form an insoluble white oxide that has a melting point of 1910°C. The oxide of E conducts electricity only when liquid. Suggest the type of bonding shown by the oxide of E. Explain your answer.[2]
13. (e)(ii)E also reacts readily with Cl2(g) to form a white solid that reacts exothermically with water. The resulting solution reacts with aqueous silver nitrate to form a white precipitate that dissolves in dilute ammonia. Suggest the type of bonding shown by the chloride of E. Explain your answer.[2]