Reacting metals with oxygen

3. + metal oxygen  metal oxide Reacting metals with oxygen Most metals react with oxygen. Some metals react quickly and some only react very slowly. Magnesium, for example, burns in oxygen with a bright flame. When a metal reactswith oxygen, the product is a metal oxide. This is called an oxidation reaction.

4. Investigating reactivity with oxygen

5. Order of reactivity with oxygen

6. + magnesium oxygen  magnesium oxide + 2Mg O2  2MgO + copper oxygen  copper oxide + 2Cu O2  2CuO + iron oxygen  iron oxide + 4Fe O2  2Fe2O3 Equations: reactions of metals with oxygen What is the balanced symbol equation for each reaction?

7. What happens to the mass?

8. Metals and oxygen: true or false?

10. Metals and water The Romans used lead to make water pipes but didn’t know that lead reacts slowly with water and makes itpoisonous! Some metals react vigorously with water, some metals react slowly and some do not react at all. Which is the best type of metal to use for water pipes?

11. Using unreactive metals The words ‘plumber’ and ‘plumbing’ come from plumbum (the Latin word for lead) because the ancient Romans used lead for their water pipes. Why is lead no longer used in plumbing? Copper is a much better metal for water pipes because it does not react at all with water – perhaps plumbers should be renamed coppers!

12. + + metal water  metal hydroxide hydrogen Reacting metals with water When any metal reactswith water, the products are a metal hydroxide and hydrogen gas. This is the general equation for the reaction of a metal with water: What tests could you do to show that hydrogen and a hydroxide have been produced?

13. Investigating reactivity with water (I)

14. potassium hydroxide + + potassium water  hydrogen + + 2K 2H2O  2KOH H2 lithium hydroxide + + lithium water  hydrogen + + 2Li 2H2O  2LiOH H2 sodium hydroxide + + sodium water  hydrogen + + 2Na 2H2O  2NaOH H2 Equations: reactions of metals with water What is the balanced symbol equation for each reaction?

15. metal reaction with water reacts slowly with cold water but reacts quickly with steam gold calcium no reaction silver no reaction zinc no reaction Investigating reactivity with water (II) James investigated how reactive some metals were with water. He made these observations: Copper is used in plumbing and silver and gold in jewellery. Why are these unreactive metals suitable for such uses?

16. Order of reactivity with water

17. Odd one out

19. + iron oxygen  iron oxide + 2Fe 3O2  Fe2O3 Corrosion of metals Metals corrode when they are left in contact with air or water. Which metals corrode quickly and which corrode slowly? When iron corrodes, it is called rusting. Rusting is the oxidation reaction of iron with oxygen in the presence of water.

20. Does salt make iron rust faster? People who live by the seaside often claim that their cars go rusty faster. Does salt speed up the rate of the rusting reaction?

21. What is needed for iron to rust?

22. plastic coating painting galvanising oiling Preventing rust Rusting destroys a huge amount of iron and steel every day. People spend a lot of money making sure that their iron and steel buildings, engines, lorries and ships do not rust. What methods could you use to prevent things rusting?

23. reactive metal iron Rusting: sacrificial protection Sacrificial protection is another way of preventing rust. This involves attaching big blocks of magnesium or zinc to the iron hull of a ship or water pipe. Because magnesium is more reactive than iron, it corrodes first, leaving the iron intact. Eventually the magnesium blocks have to be replaced because they have corroded completely away.

24. Rusting: true or false?

26. Reacting metals with acid

27. Order of reactivity with acid

28. Reactivity of metals sodium calcium magnesium aluminium zinc iron lead hydrogen copper Metals can be listed in order of how reactive they are. This list is called the reactivity series. • The more reactive the metal, the more vigorous the reaction. increasing reactivity • A metal that is below hydrogen will not react with dilute acids.

29. + + metal acid  metal salt hydrogen Products of metal reacting with acid When metals react with acid, bubbles of gas are produced. The ‘squeaky pop’ test shows that this gas is hydrogen. When a metal reacts with acid, the products are hydrogen gas and a metal salt. What is the general equation for the reaction of a metal with acid?

30. + + Mg 2HCl  MgCl2 H2 + + 2Al 6HCl  2AlCl3 3H2 + + Zn 2HCl  ZnCl2 H2 Metals and hydrochloric acid – equations What is the balanced symbol equation for each reaction? magnesium + hydrochloric acid magnesium chloride + hydrogen  aluminium + hydrochloric acid  aluminium chloride + hydrogen zinc + hydrochloric acid  zinc chloride + hydrogen

31. + + metal acid  salt hydrogen Reaction of metals with acids When a metal reacts with an acid, the products are a salt and hydrogen gas. The salt produced depends on the metal and type of acid involved in the reaction: • When a metal reacts with hydrochloric acid, the salt produced is a metalchloride. • When a metal reacts with sulfuric acid, the salt produced is a metal sulfate. • When a metal reacts with nitric acid, the salt produced is a metal nitrate.

32. What is the equation?

33. Word equations for metals and acids

34. Balancing equations for metals and acids

36. with water with oxygen with acid potassium calcium calcium sodium magnesium magnesium lithium zinc aluminium magnesium iron zinc copper lead iron silver copper lead gold copper Comparing reactivity The orders of reactivity of metals with water, oxygen and air can be compared. What patterns can you see in these lists?

37. The reactivity series Combining the information from all the reactions gives an overall order of reactivity called the reactivity series. One way to remember this order is to learn this silly sentence: please send charlie’s monkeys and zebras in large cages securely guarded!

38. What is the order of reactivity?

39. potassium sodium calcium magnesium aluminium zinc iron lead copper silver gold increasing reactivity Using the reactivity series The reactivity series can be used to make predictions about the reactions of metals. Predictions can be made about simple reactions of metals with oxygen, water and acids. Predictions can also be made about more complex reactions where one metal is competing with another.

40. reacts with prediction metal gold acid calcium water sodium oxygen silver oxygen zinc oxygen Predicting simple reactions Use the reactivity series to predict if a reaction will take place and how intense the reaction will be: no reaction fizzing burns vigorously very slow reaction burns moderately

41. oxygen in the atmosphere coating of oxygen atoms aluminium atoms Aluminium According to the reactivity series, aluminium should be a fairly reactive metal, but in reality it often appears unreactive. Why? This is because a protective layer of aluminium oxide quickly forms on its surface, which stops it reacting. This means aluminium can be used to build aeroplanes and saucepans. However, if the protective layer is removed, the aluminium reacts more quickly.

42. The reactivity series: summary

43. iron oxide aluminium oxide + + aluminium  iron What is a displacement reaction? The Thermit reaction is an example of a displacementreaction. In this reaction, aluminium reacts with iron oxide to make aluminium oxide and iron. The more reactive aluminium takes the oxygen from the less reactive iron. The reaction gets so hot that the iron melts! It is used to weld railway tracks.

44. before after copper sulfate magnesium sulfate + + magnesium  copper Displacement in action What happens when magnesium reacts with copper sulfate? Why does the blue colour of the copper sulfate solution gradually disappear during this reaction? Magnesium is a more reactive metal than copper and so the magnesium displaces the copper from the copper sulfate solution. This is why the blue colour disappears.

45. more reactive metal less reactive metal compound more reactive metal compound less reactive metal + +  less reactive metal more reactive metal compound no reaction +  Explaining displacement reactions The reactivity series can be used to predict if a metal will react with a metal compound. If the metal is more reactive than the metal in the compound, it pushes out, or displaces, the less reactive metal from its compound. If the metal is less reactive than the metal in the compound, it will not compete and so there is no reaction.

46. copper chloride magnesium chloride + + magnesium  copper magnesium chloride + silver  no reaction Displacement reactions – examples Will magnesium react with copper chloride? Magnesium is a more reactive metal than copper, so magnesium displaces the copper from its compound. Will silver react with magnesium chloride? Silver is a less reactive metal than magnesium, so silver does not displace the magnesium from its compound.

47. + + iron oxide carbon  carbon dioxide iron + + copper oxide carbon  carbon dioxide copper Displacement in extracting metals Displacement reactions can be used to extract metals from their ores. For example, iron and copper are extracted from their oxides by reacting the ores with carbon:

48. Displacement reactions – activity

49. magnesium oxide + aluminium magnesium chloride + iron copper nitrate + gold Displacement reactions Use the reactivity series to predict if each mixture will react and complete the word equation. aluminium oxide + magnesium  iron chloride + magnesium  + silver zinc oxide  no reaction + copper gold nitrate 