Metals

Question 1

Copper-rich ores are running out. New ways of extracting copper from low grade ores are being researched. Recycling of copper may be better than extracting copper from its ores. Explain why. (3 marks)

Answer 1

Any three explanations from:
For recycling
• less acid rain (pollution)
• copper reserves last longer / conserved
Or
•	do not run out
• energy for extraction (saved)
or
•	less energy required
• less mining / quarrying
• less waste (copper) / electrical
appliances dumped
or
less landfill
Against recycling
• collection problems
• transport problems
• difficult to separate copper from appliances
• energy used to melt the collected copper

Question 2

What is the meaning of the term ore? (1 mark)

Answer 2

• Contain enough metal to make it economical / worth while to extract

Question 3

Iron can be produced by reacting iron oxide with carbon in a blast furnace. What type of reaction produces the iron? (1 mark)

Answer 3

Reduction

Question 4

List three typical properties of transition metals. (3 marks)

Answer 4

Shiny; easily bent or hammered into shape/ malleable; good conductors of heat and electricity

Question 5

Pure iron is relatively soft and not very strong. The iron from the blast furnace is very hard and brittle. It contains about 4% carbon and is used as cast iron. Explain the differences in the properties of pure iron and cast iron. (3 marks)

Answer 5

Pure Iron
- (in pure metal all the atoms are the same size and) able to slip / slide over each other . (property soft)
Cast iron
- (in cast iron) different sized atoms / larger atoms or structure is distorted / disrupted
- so it is difficult for layers of atoms to slip / slide over each other

Question 6

What does reduction mean? (1 mark)

Answer 6

Removal of oxygen

Question 7

Give one property of titanium that makes it more useful than steel for hip replacement joints. (1 mark)

Answer 7

• light(er) / less dense
• resistant to acids / alkalis /chemical
• resistant to corrosion

Question 8

The use of titanium is limited because it is expensive. Explain why titanium costs more than steel. (3 marks)

Answer 8

• takes a long time to process
• low abundance (of ore)
• small amount produced
• batch process used or blast furnace is continuous
• more stages used to manufacture titanium
• more energy used (per tonne of titanium)
• labour intensive

Question 9

Suggest the benefits of recycling aluminium. (3 marks)

Answer 9

• resources / aluminium / ores are conserved
• less / no mining or less associated environmental problems eg quarrying / eyesore / dust / traffic / noise / loss of land / habitat
• less / no waste (rock) / landfill
• no purification / separation (of aluminium oxide)
• (aluminium extraction / production) has high energy / electricity / heat / temperature requirements
• less carbon dioxide produced

Question 10

Pure aluminium is rarely used for the construction of large objects. Small amounts of other metals are usually mixed with aluminium. Explain why. (2 marks)

Answer 10

Statement (1 mark) link to reason (1 mark)
(pure) Al / it is weak / soft (1) as layers / rows can slide (over each other) (1)
or
alloy / other metals / they makes it stronger / harder (1) stops layers / rows sliding over each other (1)

Question 11

Why is iron described as an element? (1 mark)

Answer 11

(because iron is made up of only) one type of atom (not thing!!!)

Question 12

Suggest why pure iron would not be suitable for a hip replacement joint. (1 mark)

Answer 12

not strong
ignore soft / corrosive / flexible
accept it rusts / corrodes or that it could wear away
accept could change shape / bend
accept layers / atoms could slide (over each other)

Question 13

Explain why stainless steel is harder than pure iron. (2 marks)

Answer 13

has different sized atoms / particles
or
structure is different/distorted / disrupted
so it is difficult for layers / atoms / particles to slip / slide (over each other)

Question 14

Suggest how blowing oxygen into molten cast iron removes most of the carbon. (2 marks)

Answer 14

reacts with carbon / C

- carbon dioxide / CO2 / gas is formed / given off

Question 15

Why are different metals sometimes added to molten carbon steels? (1 mark)

Answer 15

• change / improve properties

- accept to make alloys

Question 16

The UK government has set targets for the percentage of iron and steel to be recycled.
In 2006 the target was exceeded. Suggest two reasons why the UK government wants to encourage recycling of iron and steel. (2 marks)

Answer 16

• to conserve ores / iron
• to prevent the use of landfills
• to conserve energy / fuel
• to reduce carbon / carbon dioxide emissions
• to meet EU / International targets

Question 17

Aluminium is the most abundant metal in the Earth’s crust. Suggest two reasons why we should recycle aluminium drinks cans. (2 marks)

Answer 17

any two from:
- saves resources / non-renewable
- landfill problem
- saves energy / fuel / electricity
- less carbon dioxide / carbon emissions or reduces carbon footprint
- less quarrying / mining
accept aluminium / ore will run out or conserves aluminium
accept aluminium does not corrode
ignore global warming
ignore consequences of
quarrying / mining
ignore pollution / harms environment / costs / easy to recycle

Question 18

Titanium is extracted from the titanium chloride by reacting it with sodium at 1000 °C in a reactor. Suggest why the reactor contains argon and not air. (1 mark)

Answer 18

• sodium / titanium would react with oxygen / air
• sodium / titanium does not react with argon
  accept air / oxygen is reactive
  accept argon is unreactive / inert / a noble gas / in group O

Question 19

Iron from a blast furnace is called cast iron and contains about 4% carbon. Why is pure iron softer than cast iron? (1 mark)

Answer 19

layers / atoms in pure iron are able to slide over each other
or
layers / atoms in cast iron are unable to slide over each other (easily)

Question 20

Steel is made by reducing the percentage of carbon in cast iron and then adding different metals to form the type of steel required. In the UK we use about 1.8 billion steel cans every year but only 30% of these are recycled. Recycling reduces waste. Producing steel from recycled cans requires only 25% of the energy needed to make steel from iron ore. Give three environmental benefits of recycling a higher percentage of used steel cans. (3 marks)

Answer 20

any three from:

• less iron ore used
• less other metals extracted / used to make different steels
• less fuel used
• less specified pollution
• less / no landfill space needed
• less / no mining needed or fewer specified effects of mining

Question 21

Why can iron be used to get copper from copper sulphate solution? (1 mark)

Answer 21

iron displaces copper from solutions of its salts

accept iron is more reactive than copper

Question 22

Give two advantages of phytomining compared to the traditional method of quarrying. (2 marks)

Answer 22

• less expensive/energy to extract the small amounts of copper
• plants will remove carbon dioxide from the atmosphere as they grow
• can release energy when plants are burned

Question 23

Suggest one disadvantage of phytomining. (1 mark)

Answer 23

not continuous as it takes a long time for plants to grow.

Question 24

Describe how copper is extracted by phytomining and bioleaching. Give an advantage of each process. (4 marks)

Answer 24

Phytomining involves planting certain plants on low-grade copper ores. The plants absorb copper compounds. Burning the plants produces ash that is rich in copper compounds. An advantage of this process is that it can extract copper from low-grade ores, which would not be economic to extract in other ways. Bioleaching involves bacteria, which obtain their nutrients and energy from copper compounds in low-grade copper ores. The bacteria produce solutions of copper compounds. Chemical reactions or electrolysis extract copper metals from these solutions. Again, an advantage of this process is that it can extract copper from low-grade ores, which would not be economic to extract in other ways.

Question 25

Use ideas about particles and properties to explain why aluminium alloys are used in aeroplanes and not the pure metal. (2 marks)

Answer 25

Pure aluminium is not strong enough to be used in aeroplanes. Mixing aluminium with small amounts of other metals makes alloys. Aluminium alloys are stronger than pure aluminium because the atoms of the other metals disrupt the regular pattern of atoms in aluminium, meaning the atoms can slide over each other less easily.