1. What is the same about them? 06/06/2016 They both contain copper ions Cu 2+

2. Learning objectives All Recall how copper can be extracted from its ore and explain why this is an example of reduction. State that copper can be purified by electrolysis and label the apparatus used. Explain some of the advantages and disadvantages of recycling copper. Some describe what happens at each electrode in words and using half-equations. 06/06/2016

3. Title: Extracting copper The ore from which copper is extracted. Its green colour comes from copper carbonate. Copper carbonate can be separated from the rock, but two chemical reactions are needed to extract the copper element. 06/06/2016 Malachite

4. Two-step process: Copper carbonateCopper oxideCopper 06/06/2016 Thermal decomposition Reduction (removing oxygen)

5. Heading: 1.Thermal decomposition of copper carbonate to copper oxide 06/06/2016 1.Write a word equation for the reaction. 2.Write a symbol equation for the reaction, including state symbols. 3.What test can we use to prove that carbon dioxide is one of the products? 4.What colour change do we see if carbon dioxide is present? 1.Write a word equation for the reaction. 2.Write a symbol equation for the reaction, including state symbols. 3.What test can we use to prove that carbon dioxide is one of the products? 4.What colour change do we see if carbon dioxide is present?

6. Answers 1. Word equation copper carbonate → copper oxide + carbon dioxide 2. Symbol equation CuCO 3(s) → CuO (s) + CO 2(g) 3. Test for carbon dioxide Bubble the gas through limewater 4. Colour change observed Turns limewater cloudy/milky 06/06/2016

7. Heading 2.Extracting copper from copper oxide To obtain copper metal, the oxygen needs to be removed from the copper oxide. Carbon is used to take this oxygen away to make carbon dioxide and leave the copper element. 06/06/2016 Reduction = the removal of oxygen The opposite is oxidation (adding oxygen)

8. copper oxide and carbon Bunsen burner tripod metal tray Method: 1.Mix two spatulas of copper oxide with four spatulas of charcoal powder in a disposable cup. 2.Pour the mixture into a pile in the centre of a metal tray and cover the pile with small pieces of carbon. 3.Heat the mixture strongly for 10 minutes. 4.Use tongs to tip the mixture into a beaker of water. Any copper will sink to the bottom. 5.Swirl the beaker and pour the water and carbon into a waste bucket, leaving the copper in the bottom of the beaker. 6.Add more water, swirl and tip it out again, to clean the copper. Wear goggles Task: Write word and symbol equations for the reaction Is it balanced? Task: Write word and symbol equations for the reaction Is it balanced?

9. Equations Copper oxide + carbon → copper + carbon dioxide CuO + C → Cu + CO 2 06/06/2016 22

10. Extracting Copper Although copper is extracted it is still not pure enough to use for electrical wiring. The conductivity of copper is drastically reduced by tiny amounts of impurities. Because of this, most copper metal is further purified by electrolysis.

11. Extracting copper questions 1.What can you heat copper ore with to get copper out? 2.Why can smelted* copper not be used to make things? 3.List two reasons why recycling copper is cheaper than extracting it from its ore. 4.List two potential problems with recycling copper. *Smelting = heating an ore to extract the metal 06/06/2016

12. Extracting copper answers 1.What can you heat copper ore with to get copper out? Carbon 2.Why can smelted copper not be used to make things? It’s impure 3.List two reasons why recycling copper is cheaper than extracting it from its ore. Saves resources – we don’t need so many huge copper mines (copper ore is a finite resource). Saves the energy needed to crush rocks and operate smelters and electrolysis cells. 4.List two potential problems with recycling copper. Getting people to recycle it in the first place. Sorting the copper from other metals and impure copper. 06/06/2016

13. Recap questions – Copper extraction Although copper is extracted through smelting (copper oxide + carbon → copper + carbon dioxide), it is still not pure enough to use for electrical wiring. Why? The conductivity of copper is drastically reduced by tiny amounts of impurities. How do we further purify the copper? By electrolysis.

14. What is electrolysis? The process of breaking down compounds in solution, or when molten, to form two products. One product is formed at the negative electrode, the other at the positive electrode. 06/06/2016

15. Key words Electrolyte: the solution or molten compound Anode: +ve electrode Cathode: -ve electrode Anions: -ve ions that are attracted to the anode Cations: +ve ions that are attracted to the cathode 06/06/2016

16. Copper is purified by electrolysis. Electricity is passed through solutions containing copper sulphate (electrolyte). The anode - the positive electrode is impure copper The cathode - the negative electrode is where pure copper forms. Title: Purification of copper through electrolysis 06/06/2016

17. An electrolysis cell 06/06/2016 e.g. Cu 2+ cations e.g. SO 4 2- anions

18. Title: Purification of copper through electrolysis electrode copper sulfate solution 1.Set up the circuit shown in the diagram. The electrodes should be clamped to the rim of the beaker with crocodile clips and must not touch. 2.Adjust the voltage of the power pack to give a current of about 0.5 A. 3.Leave the experiment running for 10 minutes. 4.Remove the electrodes from the beaker and lay them on a paper towel. 5.One electrode should look pale and clean as if its surface has been removed. The other electrode should be coated with a layer of fresh copper. Note the appearance of each electrode. 6.Deduce what happened to the copper atoms that disappeared from the + electrode. Wear goggles Copper dissolves at the anode by becoming copper ions. These move through the solution and gain electrons at the cathode, and turn back into copper metal atoms.

19. Copper ions form at the anode Impure copper is used as the anode of an electrolysis cell. The battery pulls electrons off the copper atoms in the anode. By losing electrons these atoms become copper ions and so the anode slowly ‘dissolves’ away. Impurities just sink to the bottom as ‘anode mud’.

20. Copper atoms at the cathode Opposite charges attract. Positive copper ions (Cu 2+ ) move to the negative cathode. At the cathode these ions gain electrons and turn into copper atoms. So, during electrolysis a copper cathode gets thicker.

21. Purification: The whole process

22. Purification of copper Copy and complete the diagram by adding these labels: anode cathode copper dissolves here copper is plated here copper(II) sulphate electrolyte impure copper power pack pure copper 06/06/2016

23. Purification of copper: The half equations Anode (+ve electrode) – impure copper Cu(s) → Cu 2+ (aq) + 2e - Cathode (-ve electrode) – where pure copper forms Cu 2+ (aq) + 2e - → Cu(s)

24. 06/06/2016 copper oxide (CuO) a compound made of ions copper (Cu) an element made of atoms

25. To free a metal from a compound, these ions need to be converted back into atoms. This happens when carbon removes oxygen from copper oxide. This is reduction. So reduction has two meanings: 1.Loss of oxygen2. Gain of electrons a)Deduce what two ions copper sulfate (CuSO 4 ) contains. ___________________________________________ b)What must copper atoms lose to become copper ions? ___________________________________________ Cu 2+, SO 4 2- Two electrons OIL Oxidation Is Loss of electrons RIG Reduction Is Gain of electrons OIL Oxidation Is Loss of electrons RIG Reduction Is Gain of electrons

26. Copper is purified to improve its NOT CIVIC DUTY Copper is purified by CELERY IS LOST Pure copper forms at the DO TEACH Impurities form called A ODD MENU The anode will slowly DIVE LOSS At the cathode copper ions gain CORN STEEL conductivity electrolysis cathode anode mud dissolve electrons Unscramble the words to end the sentences

27. Learning objectives All Recall how copper can be extracted from its ore and explain why this is an example of reduction. State that copper can be purified by electrolysis and label the apparatus used. Explain some of the advantages and disadvantages of recycling copper. Some describe what happens at each electrode in words and using half-equations. F = Fully understand C = Competent D = Development 06/06/2016

29. Why aren’t these in the periodic table? 06/06/2016 Steel Bronze Brass Solder Alloys a mixture of a metal element with another element Alloys a mixture of a metal element with another element

30. Learning objectives All Recall that alloys are mixtures containing one or more metal elements. Recognise that brass, bronze, solder, steel, and amalgam are alloys, name the metals in them and recognise their large scale uses. Recognise that the properties of an alloy are different from the properties of the metals in it. Some Link the properties of alloys to their uses. Explain why ‘smart alloys’ are so useful. 06/06/2016

31. Why are most metallic objects made from alloys? Adding small amounts of other substances to a metal can enhance its properties. E.g. solder is an alloy of… …lead and tin. This makes it melt and solidify over a range of temperatures, enabling it to be squeezed into cracks while it is semi-solid.

32. Title: Comparing melting points 06/06/2016 1.Place samples of lead, tin and solder at equal distances from the centre of a metal tray, and note the position of each sample. 2.Heat strongly from the centre with a roaring Bunsen flame. 3.Note the order in which the metals melt. 4.The solder is a mixture of tin and lead. How does mixing the metals affect their melting point? Wear eye protection at all times. Hair and ties tied back / tucked in. Wash your hands at the end of the practical. Wear eye protection at all times. Hair and ties tied back / tucked in. Wash your hands at the end of the practical. Extn. Pg 152-153, Q6-9 in full sentences

33. Right for the job Use page 153 to help with the following: a)Link up the words in each column so that each row reads correctly. b)Use the data in the table to answer the question. 06/06/2016

34. Smart alloys If you wear glasses, can you bend the frame without breaking it? If you can, the frames are probably made from a smart alloy. 06/06/2016

35. Heading: Smart alloys Nitinol is a smart alloy made from nickel and titanium, and is used in spectacle frames and teeth braces. When deformed by force, the alloy is formulated to spring back into shape above a certain threshold temperature. This is called ‘shape memory’. Answer Q3 Nitinol, parts a-e, on the sheet. Extn. Read the purple section on pg 153. Explain how smart alloys are used in heart stents and shower heads. 06/06/2016

36. Nitinol Answers Q3a If bent it springs back into shape. Q3b They would return to their original shape after a crash. Q3c They exert a constant force as they try to return to their original length. Q3d By changing shape when the room reaches a certain temperature. Q3e By using electricity to heat them. 06/06/2016

37. Learning objectives All Recall that alloys are mixtures containing one or more metal elements. Recognise that brass, bronze, solder, steel, and amalgam are alloys, name the metals in them and recognise their large scale uses. Recognise that the properties of an alloy are different from the properties of the metals in it. Some Link the properties of alloys to their uses. Explain why ‘smart alloys’ are so useful. F = Fully understand C = Competent D = Development 06/06/2016