Obtaining and using metals

Question 1

give two ways of extracting metals from their ores

Answer 1

heating with carbon, electrolysis

Question 2

give an example of extracting a metal by heating it with carbon

Answer 2

metals such as iron are extracted from their compounds by heating the ores with carbon.

Question 3

give a word equation of heating iron with carbon

Answer 3

iron oxide + carbon > iron + carbon dioxide

Question 4

give an example of extracting a metal by electrolysing it

Answer 4

reactive metals such as aluminium are extracted by melting the ore and then carrying out electrolysis. electrolysis decomposes aluminium oxide.

Question 5

give a word equation of electrolysing aluminium oxide

Answer 5

aluminium oxide > aluminium + oxygen

Question 6

Explain why the method used to extract a metal is related to its position in the reactivity series and cost of the extraction process

Answer 6

most reactive elements are the hardest and most expensive to extract and they are extracted through electrolysis of a molten compound. less reactive, the easiest and cheapest to extract.

Question 7

what an oxidation reaction

Answer 7

a reaction where oxygen is gained

Question 8

what an reduction reaction

Answer 8

a reaction where oxygen is lost

Question 9

does the extraction of metals involve oxidation or reduction

Answer 9

it involves reduction

Question 10

what does the oxidation of metals cause

Answer 10

it causes corrosion

Question 11

what is the link between a metals resistance to corrosion and its position on the reactivity series.

Answer 11

the most reactive metals are the least resistant to corrosion and they corrode the fastest. metals lower in the reactivity series are more resistant to corrosion and corrode the slowest. the metals lowest in the reactivity series are most resistant to corrosion and do not corrode at all.

Question 12

give 6 advantages of recycling metals

Answer 12

1) means that the earth’s supply of metals will last longer
2) if metals are recycled we need fewer mines. this helps the environment, because mining causes dust and noise pollution and damages the landscape.
3) produces less pollution
4) less land is needed for landfill sites
5) carbon dioxide is emitted when fossil fuels are used to heat ores or to generate electricity used in electrolysis. so far less carbon dioxide is emitted by the recycling process, as less energy is needed.
6) it takes less energy to melt down used metals than it does to extract the metal from its ore. this makes some recycled metals more sustainable and cheaper.

Question 13

Describe the uses of gold in relation to its properties

Answer 13

used for jewellery because it looks attractive and it does not corrode. used in some electrical connections inside electronic devices because it is one of the best electrical conductors.

Question 14

Describe the uses of copper in relation to its properties

Answer 14

used for electrical cables because it is a very good conductor of electricity. used in water pipes because it does not corrode easily

Question 15

Describe the uses of steel in relation to its properties

Answer 15

used for bridges, cars and buildings because it is strong and resistant to corrosion.

Question 16

Describe the uses of aluminium in relation to its properties

Answer 16

used for drinks cans because it does not corrode. used in aeroplanes and some cars because it has a low density

Question 17

why converting pure metals into alloys

often increases the strength of the product

Answer 17

in a pure metal the layers of atoms can slide over each. an alloy is stronger, because the atoms of the added metal are different sizes and they jam up the structure and stop the layers from sliding.

Question 18

give an example of a alloy

Answer 18

steel is an alloy of ion with small amounts of other metals and some carbon. steel is stronger than iron and more resistant to corrosion.

Question 19

describe how gold is alloyed

Answer 19

pure gold is alloyed with other metals to make it stronger and harder.

Question 20

describe smart or shape memory alloys, give an example

Answer 20

smart materials have different properties in different conditions. shape memory alloys are smart materials, as their shape changes when the temperature changes. nitinol is an alloy of nickel and titanium. if the shape of something made from nitinol is changed, it will return to its original shape when it is heated.

Question 21

give a use of shape memory alloys

Answer 21

shape memory alloys are used to make spectacle frames. these alloys are examples of new materials developed to meet new needs.

Question 22

give one use of nitinol

Answer 22

it is used to keep arteries open. a stent is made from a tube of nitinol, which is cooled and squashed, so it is small enough to slide into the blocked artery. when the nitinol warms up to body temperature it resumes its original shape and holds the artery open.

Question 23

what does carats measure

Answer 23

the percentage of gold in a gold alloy

Question 24

what does fineness mean

Answer 24

fineness is the parts per thousand of gold in the alloy