1. Water

2. Describe chemical tests for the presence of water using anhydrous cobalt(II) chloride and anhydrous copper(II) sulfate
3. Describe how to test for the purity of water using melting point and boiling point
4. Explain that distilled water is used in practical chemistry rather than tap water because it contains fewer chemical impurities
5. State that water from natural sources may contain substances, including:
6. (a) dissolved oxygen
7. (b) metal compounds
8. (c) plastics
9. (d) sewage
10. (e) harmful microbes
11. (f) nitrates from fertilisers
12. (g) phosphates from fertilisers and detergents
13. State that some of these substances are beneficial, including:
14. (a) dissolved oxygen for aquatic life
15. (b) some metal compounds provide essential minerals for life
16. State that some of these substances are potentially harmful, including:
17. (a) some metal compounds are toxic
18. (b) some plastics harm aquatic life
19. (c) sewage contains harmful microbes which cause disease
20. (d) nitrates and phosphates lead to deoxygenation of water and damage to aquatic life
21. Details of the eutrophication process are not required
22. Describe the treatment of the domestic water supply in terms of:
23. (a) sedimentation and filtration to remove solids
24. (b) use of carbon to remove tastes and odours
25. (c) chlorination to kill microbes

26. Fertilisers

27. State that ammonium salts and nitrates are used as fertilisers
28. Describe the use of NPK fertilisers to provide the elements nitrogen, phosphorus, and potassium for improved plant growth

29. Air Quality and Climate

30. State the composition of clean, dry air as approximately 78% nitrogen, N2, 21% oxygen, O2, and the remainder as a mixture of noble gases and carbon dioxide, CO2
31. State the source of each of these air pollutants, limited to:
32. (a) carbon dioxide from the complete combustion of carbon-containing fuels
33. (b) carbon monoxide and particulates from the incomplete combustion of carbon-containing fuels
34. (c) methane from the decomposition of vegetation and waste gases from digestion in animals
35. (d) oxides of nitrogen from car engines
36. (e) sulfur dioxide from the combustion of fossil fuels which contain sulfur compounds
37. State the adverse effect of these air pollutants, limited to:
38. (a) carbon dioxide: higher levels of carbon dioxide leading to increased global warming, which leads to climate change
39. (b) carbon monoxide: toxic gas
40. (c) particulates: increased risk of respiratory problems and cancer
41. (d) methane: higher levels of methane leading to increased global warming, which leads to climate change
42. (e) oxides of nitrogen: acid rain, photochemical smog, and respiratory problems
43. (f) sulfur dioxide: acid rain
44. Describe how the greenhouse gases carbon dioxide and methane cause global warming, limited to:
45. (a) the absorption, reflection, and emission of thermal energy
46. (b) reducing thermal energy loss to space
47. State and explain strategies to reduce the effects of these environmental issues, limited to:
48. (a) climate change: planting trees, reduction in livestock farming, decreasing use of fossil fuels, increasing use of hydrogen and renewable energy, e.g., wind, solar
49. (b) acid rain: use of catalytic converters in vehicles, reducing emissions of sulfur dioxide by using low-sulfur fuels and flue gas desulfurisation with calcium oxide
50. Describe photosynthesis as the reaction between carbon dioxide and water to produce glucose and oxygen in the presence of chlorophyll and using energy from light
51. State the word equation for photosynthesis,
52. carbon dioxide + water → glucose + oxygen
53. Explain how oxides of nitrogen form in car engines and describe their removal by catalytic converters, e.g., 2CO + 2NO → 2CO2 + N2
54. State the symbol equation for photosynthesis,
55. 6CO2 + 6H2O → C6H12O6 + 6O2

56. Corrosion of Metals

57. State the conditions required for the rusting of iron and steel to form hydrated iron(III) oxide
58. State some common barrier methods, including painting, greasing, and coating with plastic
59. Describe how barrier methods prevent rusting by excluding oxygen or water
60. Describe the use of zinc in galvanising as an example of a barrier method and sacrificial protection
61. Explain sacrificial protection in terms of the reactivity series and in terms of electron loss