Metals

Question 1

What happens in a displacement reaction

Answer 1

The more reactive metal displaces the other and ends up in solution

Question 2

What is a spectator ion

Answer 2

An ion that is in the reaction but doesn’t take part

Question 3

How do you write the ionic equation

Answer 3

Split all compounds into its ions
& Cross out the spectator ions

Question 4

How can you measure reactivity with different solutions in a reaction

Answer 4

See which has the most vigorous reaction

Question 5

What is the life cycle assessment

Answer 5

Assesses wether something is ‘worth’ recycling

Question 6

Name 3 advantages of recycling

Answer 6

Conserves natural reserves of metal ores so need to mine is reduced
Less waste metal ends up in landfill sites
Less pollution produced

Question 7

Name 3 disadvantages of recycling

Answer 7

Difficult to sort materials
Cost and energy used in collection is high
Sometimes it can be more expensive to recycle than to extract new metals

Question 8

List the steps in the life cycle of a metal

Answer 8

Metal ore is extracted
Pure metal is extracted from its ore by electrolysis
Metal is shaped and processed into product
Product is sold and used by consumer
Product is thrown into landfill or recycled

Question 9

How can you tell if it is better to recycle or to extract new metal

Answer 9

If more energy is required to extract the new metal then it is better to recycle

Question 10

What is an ore

Answer 10

A rock containing a metal compound
There needs to be enough of it for extraction to be economically viable

Question 11

What can reduction also mean other than gain of electrons

Answer 11

Loss of oxygen

Question 12

What can oxidation also mean other than loss of electrons

Answer 12

Gain of oxygen

Question 13

What are redox reactions

Answer 13

A reaction in which oxidation AND reduction take place
Eg. Electrolysis

Question 14

Is a metal being isolated from their ore reduction or oxidation

Answer 14

ALWAYS reduction

Question 15

Metals more reactive than WHICH ELEMENT can be extracted using ELECTROLYSIS

Answer 15

Carbon

Question 16

What are the 2 ways small amounts of copper can be extracted from their ores

Answer 16

Bioleaching and phytoextraction

Question 17

What is bioleaching

Answer 17

Bioleaching uses bacteria grown on a low grade ore
The bacteria produce a solution containing copper ions called a leachate
Copper is extracted from the leachate by displacement and purified by electrolysis

Question 18

Are the melting points of transition metals typically high or low

Answer 18

High

Question 19

Do transition metals typically have high or low densities

Answer 19

High

Question 20

Name 4 properties of transition metals

Answer 20

Ductile
Shiny
Malleable
Conducts electricity

Question 21

Do transition metals typically form coloured compounds

Answer 21

Yes

Question 22

What is an alloy

Answer 22

A mixture of a metal with at least one other element

Question 23

What does adding other elements to a metal do

Answer 23

It changes the overall structure and so changes its properties

Question 24

What can scientists do by changing the amount of each element in an alloy

Answer 24

Material scientists can custom make alloys to fit a given job

Question 25

What is the alloy brass used for and why

Answer 25

Door knobs, buttons and musical instruments BECAUSE it does not tarnish

Question 26

What is the alloy amalgam used for and why

Answer 26

Dental fillings BECAUSE it can be shaped when warm and resists corrosion

Question 27

Why is yellow gold a different colour from pure gold

Answer 27

Because it is an alloy of copper and silver Adding more copper gives redder shades

Question 28

Why is steel stronger than iron

Answer 28

In pure iron the atoms are arranged in dense layers (these layers can slide over each other which means iron is quite soft) The atoms of other elements are different sizes so when they are added to iron they distort the regular structure This makes it harder for the layers to slide past each other and so increases strength

Question 29

What happens when metals react with oxygen in air

Answer 29

They oxidise to form metal oxides

Question 30

What is tarnishing

Answer 30

Metals may form a thin layer of tarnish when they oxidise This layer stops oxygen reaching the metal preventing any further oxidation Eg. Statue of Liberty

Question 31

What is corrosion

Answer 31

Corrosion happens when the metal continues to oxidise and so overtime becomes weaker

Question 32

What is rusting

Answer 32

Corrosion of iron or steel when reacting with oxygen and water

Question 33

How can rusting be prevented by keeping air away

Answer 33

metal kept in unreactive atmosphere of nitrogen or argon

Question 34

How can rusting be prevented by keeping water away

Answer 34

Use a desiccant powder that absorbs water vapour

Question 35

What are the physical barriers used to prevent rusting

Answer 35

Painting, coating with plastic, greasing and oiling

Question 36

What is sacrificial protection

Answer 36

A method of rust prevention that does not rely on keeping water and oxygen away

Question 37

How is a sacrificial metal chosen

Answer 37

Any metal that oxidises more easily than the metal that is at risk from rusting

Question 38

Explain how magnesium prevents steel from rusting

Answer 38

Magnesium is more reactive than steel Magnesium acts as the sacrificial protection as it oxidises faster than steel Mg —-> Mg2+ + 2e- Magnesium has been oxidised because it has lost electrons