Reactivity of Metals

1. Reactivity of Metals

2. Reactions of metals with oxygen METAL + OXYGEN METAL OXIDE • Copy and complete the following reactions: • Magnesium + oxygen • Copper + oxygen • Calcium + oxygen • Iron + oxygen When a metal reacts with oxygen it will form a METAL OXIDE. This is what happens when a metal rusts. We can make this reaction happen quicker by burning the metal.

3. Reactions of metals with water METAL + WATER METAL OXIDE + HYDROGEN METAL + WATER METAL HYDROXIDE + HYDROGEN • Copy and complete the following reactions: • Sodium + water • Potassium + water • Calcium + water • Iron + steam When a metal reacts with water hydrogen is always given off. The other product will be either a metal hydroxide or a metal oxide.

4. Reactions of metals with acids METAL + ACID SALT + HYDROGEN e.g. magnesium + hydrochloric acid magnesium chloride + hydrogen • Copy and complete the following reactions: • Calcium + hydrochloric acid • Zinc + hydrochloric acid • Iron + hydrochloric acid • Lithium + sulphuric acid When a metal reacts with an acid it gives off hydrogen (which can be “popped” using a lit splint). The other product is a salt.

5. Complete the following reactions: • Lithium + water • Lithium + hydrochloric acid • Silver + oxygen • Magnesium + sulphuric acid • Potassium + oxygen • Aluminium + oxygen • Manganese + water • Sodium + sulphuric acid • Lithium + oxygen • Nickel + hydrochloric acid Lithium hydroxide + hydrogen Lithium chloride + hydrogen Silver oxide Magnesium sulphate + hydrogen Potassium oxide Aluminium oxide Manganese oxide + hydrogen Sodium sulphate + hydrogen Lithium oxide Nickel chloride + hydrogen

6. An example question on reactivity

7. The Reactivity Series Increasing reactivity Potassium Sodium Calcium Magnesium Aluminium Carbon Zinc Iron Lead Copper Silver Gold The Reactivity Series lists metals in order of reactivity:

8. Displacement reactions Magnesium Copper sulphate Mg Cu SO4 The magnesium DISPLACES the copper from copper sulphate Mg SO4 Cu Magnesium sulphate Copper A displacement reaction is one where a MORE REACTIVE metal will DISPLACE a LESS REACTIVE metal from a compound.

9. Displacement reactions A displacement reaction is one where a MORE REACTIVE metal will DISPLACE a LESS REACTIVE metal from a compound. For example, if you drop some magnesium into copper sulphate a reaction will happen because magnesium is more reactive than copper, so the reaction is: Magnesium + copper sulphate copper + magnesium sulphate However, if you drop some copper into magnesium sulphate NOTHING will happen.

10. Some example reactions… Extension work – write down the equations for these reactions

11. Some example reactions… Extension work – write down the equations for these reactions

12. Extracting Metals Some definitions: A METAL ORE is a mineral or mixture of minerals from which it is “economically practical” to extract some metal. Most ores contain METAL OXIDES (e.g. rust = iron oxide). To “extract” a metal from a metal oxide we need to REDUCE the oxygen. This is called a REDUCTION reaction.

13. How do we do it? Metals ABOVE CARBON, because of their high reactivity, are extracted by ELECTROLYSIS Metals BELOW CARBON are extracted by heating them with carbon in a BLAST FURNACE Increasing reactivity These LOW REACTIVITY metals blatantly won’t need to be extracted because they are SO unreactive you’ll find them on their own, not in a metal oxide Potassium Sodium Calcium Magnesium Aluminium Carbon Zinc Iron Tin Lead Copper Silver Gold Platinum

14. Extracting metals • What is an ore? • In what form are metals usually found in the Earth? • How do you get a metal out of a metal oxide? • What is this type of reaction called?

15. The Blast Furnace 1) HAEMATITE (iron ore), limestone and coke (carbon) are fed in here 2) Hot air is blasted in here 3) The carbon reacts with oxygen from the air to form carbon dioxide. 4) The carbon dioxide reacts with more carbon to form carbon monoxide 5) Carbon monoxide reduces iron oxide to iron. The molten iron is tapped off here 6) Molten slag (waste) is tapped off here Iron oxide + carbon monoxide iron + carbon dioxide

16. Electrolysis Molecule of solid copper chloride Molecule of solid copper chloride after being dissolved Copper ion Chloride ion

17. Electrolysis = chloride ion = copper ion Electrolysis is used to extract a HIGHLY REACTIVE metal. When we electrolysed copper chloride the negative chloride ions moved to the positive electrode and the positive copper ions moved to the negative electrode – OPPOSITES ATTRACT!!!

18. Redox reactions At the positive electrode the negative ions LOSE electrons to become neutral – this is OXIDATION At the negative electrode the positive ions GAIN electrons to become neutral – this is REDUCTION These happen during electrolysis: These two processes are called REDOX REACTIONS OILRIG – Oxidation Is Loss of electrons Reduction Is Gain of electrons

19. Purifying Aluminium Aluminium has to be extracted from its ore (called ________) by electrolysis. This is because aluminium is very ___________. The ore is mixed with cryolite to lower its ________ ________. The ore is then melted so that the ions can ______. The positively charged aluminium ions gather at the ___________ electrode. Oxygen forms at the positive electrode and causes it to wear away, which means that they have to be __________ frequently. Words – melting point, replaced, negative, bauxite, reactive, move

20. Rusting Experiment NO RUST – no water NO RUST – no oxygen RUST

21. Rusting • Rust is formed when iron reacts with water AND oxygen. It’s an example of an oxidation reaction which can be sped up using salt. There are several ways of dealing with rust: • Regular painting or oiling • Galvanising – this is when iron objects are coated with zinc • Making objects out of a non-rusting metal, such as stainless steel • Attaching zinc bars to ships – the water will react with the zinc before it reacts with the iron, because zinc is more reactive