Metals and their uses

Transcription

1 Metals and their uses

2 Starter - What is a metal? From this list can you pick out proper9es of metals?

3 An economic argument? It costs a lot of money to extract metals from the compounds they are found in. Why is it worth it? Write a list of all the things that we use metals for.

4 Obtaining ores How do we get the ores out of the ground?

5 Benefits/risks Write down one benefit of mining and one risk/danger associated with it.

6 Video examples Miners in Chile hjp:// v=gr8mtntp5jw Steel / skyscrapers hjp:// v=37vigvscmky&feature=fvwrel

7 Notes to copy and complete Unreac9ve metals such as are found in the Earth as the itself. Most metals are found as that require chemical reac9ons to the metal.

8 Homework Choose a metal. Select something you haven t studied yet. (ex. Copper, Lead, Tin, Zinc, other ) Inves9gate online and write a descrip9on of how we get the pure metal Give 4 examples of the uses of that metal. Write at least half a page in your notes

9 Summary Discuss the financial benefit and expense of obtaining metals Describe how ores and metals are mined Explain that reac9ve metals need a chemical reac9on to turn them into the metal

10 Metals from ores

11 Objec9ves Must Recall the posi9on of different elements on the reac9vity series Should Descibe how the posi9on of an element on the reac9vity series determines how to extract it Could Explain that carbon is used in a blast furnace to reduce iron oxide to iron

12 Reac9vity series All metal elements have a different reac9vity. Some such as sodium are very reac9ve even in air. Others such as gold are extremely unreac9ve.

13 Finding an order? Can you place these elements in a list of reac9vity with most reac9ve a the top and least at the bojom? Copper Sodium Zinc Gold Magnesium Iron

14 How did you get on? Most reac9ve Sodium Magnesium Zinc Iron Copper Least reac9ve Gold

15 Extrac9ng metals A metal can be extracted from a compound by reac9ng with an element higher up in the reac9vity series. So for example copper is more reac9ve than silver. If we add copper metal to silver nitrate compound we make silver metal.

16 Extrac9ng iron Iron ore (haema9te) is iron oxide. To make iron we need to remove the oxygen. This process is called REDUCTION Copy down this equa9on Iron oxide + carbon Iron + Carbon dioxide

17 Extrac9ng Iron from its ore Carbon can also be put into the reac9vity series and is higher (more reac9ve) than iron. This means iron can be extracted from its ore using carbon.

18 Notes to copy and complete Metals that are reac9ve than carbon in the reac9vity series can be from their oxides by with. Iron oxide is reduced in the to make iron. [extracted, reduc9on, carbon, less, blast furnace]

19 Is it possible to obtain lead from its ore using carbon? Be prepared to say why. Most reac9ve Aluminium Zinc Carbon Iron Lead Least reac9ve Copper

20 Obtaining lead from its ore Due to its posi9on on the reac9vity series it is possible to obtain lead from its ore using carbon. This process is called REDUCTION.

21 Steelmaking and alloys

22 Objec9ves Recall that most iron is converted into steels. Describe how steels are alloys since they are mixtures of iron with carbon. Explain that alloys can be designed to have proper9es for specific uses.

23 Why make steel? Pure iron is rela9vely sol and not very strong. The iron from the blast furnace is very hard and brijle. It contains about 4% carbon and is used as cast iron. We need an iron that is in between these two extremes.

24 Basic oxygen steelmaking Carbon steels can be made by the following processes: blowing oxygen into molten cast iron to remove most of the carbon as carbon dioxide; then adding a calculated amount of carbon.

25 Video of the BOS process (Corus) hjp:// v=qo50kxlu_34&feature=fvsr

26 The BOS process

27 Copy and complete is made from cast iron by blowing into a large vessel containing molten iron. Oxygen reacts with in the iron to make carbon dioxide and carbon monoxide The steel has carbon than cast iron. is added to cool the reac9on.

28 Alloys An alloy is a metal that contains other elements. Cast iron is an alloy

29 Alloys with carbon Low carbon steel is easily shaped (more bendy). High carbon steel is hard and brijle (strong but not easily shaped).

30 Other problems

31 Why alloy? To change the proper9es for example to be: harder stronger rust less or not at all lighter heavier a different colour

32 Stainless steel This is an example of a very useful alloy of iron. It contains lots of different elements in small amounts. The most important addi9on is chromium and this stops the metal from rus9ng.

33 Other alloys Most metals in everyday use are alloys. are for many uses and so are mixed with small amounts of similar metals to make them harder.

34 Why recycle? In pairs come up with 3 main reasons why we should recycle this car?