1. IGCSE CHEMISTRY SECTION 2 LESSON 4

2. Content The iGCSE Chemistry course Section 1 Principles of Chemistry Section 2 Chemistry of the Elements Section 3 Organic Chemistry Section 4 Physical Chemistry Section 5 Chemistry in Society

3. Content Section 2 Chemistry of the Elements a)The Periodic Table b)Group 1 Elements c)Group 7 Elements d)Oxygen and Oxides e)Hydrogen and Water f)Reactivity Series g)Tests for ions and gases

4. Lesson 4 f) Reactivity Series f) Reactivity series 2.29 understand that metals can be arranged in a reactivity series based on the reactions of the metals and their compounds: potassium, sodium, lithium, calcium, magnesium, aluminium, zinc, iron, copper, silver and gold 2.30 describe how reactions with water and dilute acids can be used to deduce the following order of reactivity: potassium, sodium, lithium, calcium, magnesium, zinc, iron and copper 2.31 deduce the position of a metal within the reactivity series using displacement reactions between metals and their oxides, and between metals and their salts in aqueous solutions 2.32 understand oxidation and reduction as the addition and removal of oxygen respectively 2.33 understand the terms redox, oxidising agent, reducing agent 2.34 describe the conditions under which iron rusts 2.35 describe how the rusting of iron may be prevented by grease, oil, paint, plastic and galvanising 2.36 understand the sacrificial protection of iron in terms of the reactivity series

5. What is the REACTIVITY SERIES?

6. The REACTIVITY SERIES places metals in order of their reactivity based on how vigorously they react with water and dilute acids.

7. The Reactivity Series ELEMENT Potassium Sodium Lithium Calcium Magnesium Aluminium Zinc Iron Tin Lead Copper Silver Gold INCREASING REACTIVITY

8. The Reactivity Series ELEMENT Potassium Sodium Lithium Calcium Magnesium Aluminium Zinc Iron Tin Lead Copper Silver Gold INCREASING REACTIVITY { Very reactive

9. The Reactivity Series ELEMENT Potassium Sodium Lithium Calcium Magnesium Aluminium Zinc Iron Tin Lead Copper Silver Gold INCREASING REACTIVITY { Very reactive { Quite reactive

10. The Reactivity Series ELEMENT Potassium Sodium Lithium Calcium Magnesium Aluminium Zinc Iron Tin Lead Copper Silver Gold INCREASING REACTIVITY { Very reactive { Quite reactive { Not so reactive

11. The Reactivity Series ELEMENT Potassium Sodium Lithium Calcium Magnesium Aluminium Zinc Iron Tin Lead Copper Silver Gold INCREASING REACTIVITY { Very reactive { Quite reactive { Not so reactive { Unreactive

12. Reaction with water ELEMENT Potassium Sodium Lithium Calcium Magnesium Aluminium Zinc Iron Tin Lead Copper Silver Gold Very vigorous reaction with water, forming the hydroxide. Fizzes, and hydrogen is released. 2K (s) + 2H 2 0 (l)  2KOH (aq) + H 2(g) 2Na (s) + 2H 2 0 (l)  2NaOH (aq) + H 2(g) 2Li (s) + 2H 2 0 (l)  2LiOH (aq) + H 2(g)

13. Reaction with water ELEMENT Potassium Sodium Lithium Calcium Magnesium Aluminium Zinc Iron Tin Lead Copper Silver Gold Slow reaction with cold water (very slow in the case of magnesium) to form the hydroxide. Bubbles of hydrogen gas will be seen. Ca (s) + 2H 2 O (l)  Ca(OH) 2(aq) + H 2(g) Mg (s) + 2H 2 O (l)  Mg(OH) 2(aq) + H 2(g)

14. Reaction with water ELEMENT Potassium Sodium Lithium Calcium Magnesium Aluminium Zinc Iron Tin Lead Copper Silver Gold Do not react with cold water, but will react with steam to form the oxide. Hydrogen gas is produced. Al (s) + 3H 2 O (l)  Al 2 O 3(s) + 3H 2(g) Zn (s) + H 2 O (l)  ZnO (s) + H 2(g) Fe (s) + H 2 O (l)  FeO (s) + H 2(g)

15. Reaction with water ELEMENT Potassium Sodium Lithium Calcium Magnesium Aluminium Zinc Iron Tin Lead Copper Silver Gold No reaction with water or steam

16. Reaction with dilute acid ELEMENT Potassium Sodium Lithium Calcium Magnesium Aluminium Zinc Iron Tin Lead Copper Silver Gold These elements react with acid in a very violent and dangerous manner. These experiments would not normally be attempted in the school laboratory. Examples: 2K (s) + 2HCl (aq)  2KCl (ag) + H 2(g) 2Na (s) + H 2 SO 4(aq)  Na 2 SO 4(aq) + H 2(g) Ca (s) + 2HNO 3(aq)  Ca(NO 3 ) 2(aq) + H 2(g)

17. Reaction with dilute acid ELEMENT Potassium Sodium Lithium Calcium Magnesium Aluminium Zinc Iron Tin Lead Copper Silver Gold These elements react reasonably well with acid, and the reactivity decreases as we go down the series. Examples: Mg (s) + 2HCl (aq)  MgCl 2(ag) + H 2(g) Zn (s) + H 2 SO 4(aq)  ZnSO 4(aq) + H 2(g) Sn (s) + 2HNO 3(aq)  Sn(NO 3 ) 2(aq) + H 2(g)

18. Reaction with dilute acid ELEMENT Potassium Sodium Lithium Calcium Magnesium Aluminium Zinc Iron Tin Lead Copper Silver Gold No reaction with dilute acids

19. Displacement reactions

20. What is a DISPLACEMENT REACTION?

21. A DISPLACEMENT REACTION is one in which a more reactive metal displaces a less reactive metal from a compound.

22. In other words, a metal higher up in the reactivity series will ‘push out’ a metal that is lower in the series.

23. “deduce the position of a metal within the reactivity series using displacement reactions between metals and their oxides, and between metals and their salts in aqueous solutions.”

25. Displacement reactions Aluminium powder + iron oxide Iron plug A very violent displacement reaction occurs Magnesium ribbon fuse

26. Displacement reactions Aluminium powder + iron oxide Iron plug Magnesium ribbon fuse Aluminium + Iron oxide  Aluminium oxide + Iron

27. Displacement reactions Aluminium powder + iron oxide Iron plug Magnesium ribbon fuse Aluminium + Iron oxide  Aluminium oxide + Iron Al (s) + FeO (s)  Al 2 O 3(s) + Fe (s)

28. “deduce the position of a metal within the reactivity series using displacement reactions between metals and their oxides, and between metals and their salts in aqueous solutions.”

29. Displacement reactions Copper sulphate solution Iron sulphate solution Displacement reaction occurs Iron nail Copper deposit

30. Displacement reactions Copper sulphate solution Iron sulphate solution Displacement reaction occurs Iron nail Copper deposit A displacement reaction occurs because iron is higher than copper in the reactivity series

31. Displacement reactions Copper sulphate solution Iron sulphate solution Displacement reaction occurs Iron nail Copper deposit A displacement reaction occurs because iron is higher than copper in the reactivity series Copper sulphate + Iron  Iron sulphate + Copper

32. Displacement reactions Copper sulphate solution Iron sulphate solution Displacement reaction occurs Iron nail Copper deposit A displacement reaction occurs because iron is higher than copper in the reactivity series CuSO 4(aq) + Fe (s)  FeSO 4(aq) + Cu (s)

33. Displacement reactions Will displacement reactions occur?

34. Displacement reactions Will displacement reactions occur? METALSOLUTION WILL DISPLACEMENT HAPPEN? LeadIron sulphate LeadCopper sulphate IronZinc sulphate TinCopper sulphate

35. Displacement reactions Will displacement reactions occur? METALSOLUTION WILL DISPLACEMENT HAPPEN? LeadIron sulphateNO LeadCopper sulphateYES IronZinc sulphateNO TinCopper sulphateYES

36. Oxidation and Reduction Understand oxidation and reduction as the addition and removal of oxidation respectively

37. Oxidation and Reduction Understand oxidation and reduction as the addition and removal of oxidation respectively Oxidation may be defined in three ways: 1.Oxidation is the addition of oxygen to a substance 2.Oxidation is the removal of hydrogen from a substance 3.Oxidation is the loss of electrons from a substance

38. Oxidation and Reduction Understand oxidation and reduction as the addition and removal of oxidation respectively Examples of oxidation: S (s) + O 2(g)  SO 2(g) 2CO (g) + O 2(g)  2CO 2(g)

39. Oxidation and Reduction Understand oxidation and reduction as the addition and removal of oxidation respectively Reduction may be defined in three ways: 1.Reduction is the removal of oxygen from a substance 2.Reduction is the addition of hydrogen to a substance 3.Reduction is the gain of electrons by a substance

40. Oxidation and Reduction Understand oxidation and reduction as the addition and removal of oxidation respectively Examples of reduction: 2Pb 3 O 4(s)  6PbO (s) + O 2(g) 2NaNO 3(s)  2NaNO 2(s) + O 2(g)

41. Oxidation and Reduction Understand the terms redox, oxidising agent, reducing agent

42. Oxidation and Reduction Understand the terms redox, oxidising agent, reducing agent What is redox?

43. Oxidation and Reduction Understand the terms redox, oxidising agent, reducing agent What is redox? ?

44. In a redox reaction, both reduction and oxidation occur. For example, when hydrogen is passed over heated copper oxide, copper and water vapour are formed.

45. Oxidation and Reduction Copper oxide Anhydrous copper sulphate Dry hydrogen Excess hydrogen HEAT

46. In a redox reaction, both reduction and oxidation occur. The water vapour can be trapped by the anhydrous copper sulphate, turning it from white to blue. The excess hydrogen is burnt.

47. In a redox reaction, both reduction and oxidation occur. CuO (s) + H 2(g)  Cu (s) + H 2 O (g) HEAT

48. In a redox reaction, both reduction and oxidation occur. CuO (s) + H 2(g)  Cu (s) + H 2 O (g) HEAT OXIDATION

49. In a redox reaction, both reduction and oxidation occur. CuO (s) + H 2(g)  Cu (s) + H 2 O (g) HEAT OXIDATION REDUCTION

50. In a redox reaction, both reduction and oxidation occur. CuO (s) + H 2(g)  Cu (s) + H 2 O (g) HEAT OXIDATION REDUCTION REDOX

51. Oxidation and Reduction Understand the terms redox, oxidising agent, reducing agent

52. Oxidation and Reduction Understand the terms redox, oxidising agent, reducing agent An oxidising agent is a substance which brings about oxidation. Eg. by adding oxygen to something

53. Oxidation and Reduction Understand the terms redox, oxidising agent, reducing agent An oxidising agent is a substance which brings about oxidation. Eg. by adding oxygen to something Eg. hydrogen peroxide as an oxidising agent: H 2 O 2(l) + Na 2 SO 3(aq)  Na 2 SO 4(aq) + H 2 O (l)

54. Oxidation and Reduction Understand the terms redox, oxidising agent, reducing agent

55. Oxidation and Reduction Understand the terms redox, oxidising agent, reducing agent A reducing agent is a substance which brings about reduction. Eg. by removing oxygen from something

56. Oxidation and Reduction Understand the terms redox, oxidising agent, reducing agent A reducing agent is a substance which brings about reduction. Eg. by removing oxygen from something Eg. carbon monoxide as a reducing agent: 3CO (g) + Fe 2 O 3(s)  2Fe (s) + 3CO 2(g)

57. Oxidation and Reduction Describe the conditions under which iron rusts. Describe how the rusting of iron may be prevented by grease, oil, paint, plastic and galvanising. Understand the sacrificial protection of iron in terms of the reactivity series

58. Oxidation and Reduction Describe the conditions under which iron rusts. Describe how the rusting of iron may be prevented by grease, oil, paint, plastic and galvanising. Understand the sacrificial protection of iron in terms of the reactivity series The corrosion of iron and steel is known as rusting

59. Oxidation and Reduction Describe the conditions under which iron rusts. Describe how the rusting of iron may be prevented by grease, oil, paint, plastic and galvanising. Understand the sacrificial protection of iron in terms of the reactivity series Rusting is an oxidation process as it results it the formation of iron oxide, Fe 2 O 3

60. Oxidation and Reduction Describe the conditions under which iron rusts. Describe how the rusting of iron may be prevented by grease, oil, paint, plastic and galvanising. Understand the sacrificial protection of iron in terms of the reactivity series Rusting requires both oxygen and water. In the absence of either, iron does not rust.

61. Rusting experiment No rusting Slow rusting Fast rusting Dry airBoiled waterWater Dilute sodium chloride solution Moisture excluded Air excludedAir and water Air, water and salt Anhydrous calcium chloride Cotton wool Vaseline

62. Prevention of Rusting

63. Surfaces can be painted, greased, covered in oil or plastic.

64. Prevention of Rusting Galvanizing :- iron or steel object is dipped into molten zinc. Zinc is higher in the reactivity series, so if the surface is scratched, the zinc is oxidised in preference to the iron.

65. Prevention of Rusting Sacrificial metal, eg magnesium

66. Prevention of Rusting Sacrificial metal, eg magnesium The sacrificial metal is attached to the steel object. Since magnesium is higher than iron in the reactivity series of metals, magnesium is oxidised in preference to iron. The magnesium is used up in this process, but can be renewed.

67. End of Section 2 Lesson 4 In this lesson we have covered: The Reactivity Series of Metals Displacement reactions Oxidation and reduction Rusting