Paper 4 : C4 + C5 + C6 + C7

Question 1

Why do all group 1 elements react in the same way?

Answer 1

They all have one electron in the outer shell

Question 2

Why do all group 7 elements react in the same way?

Answer 2

They all have 7 electrons in the outer shell

Question 3

Why do group 2 elements have higher melting points than group 1 elements?

Answer 3

Group 2 elements have a higher charge

There is greater attraction between the oppositely charged ions

Question 4

What is meant by equilibrium when we are discussing reversible reactions?

Answer 4

The rate of the forwards and backwards reaction are equal

The concentrations of reactants + products remain constant

Question 5

Why is universal indicator not used in titrations?

Answer 5

Universal indicator gives a gradual colour change

A single indicator needs to be used so there is a sudden colour change

Question 6

Why does increasing the temperature increase the rate of reaction?

Answer 6

Particles move faster
More frequent collisions between reactant particles
More successful collisions between reactant particles

Question 7

What is a limiting reactant?

Answer 7

The reactant that is all used up

Question 8

Why does increasing the concentration/pressure of a reactant increase the rate of reaction?

Answer 8

More particles in the same volume

More frequent collisions

Question 9

Why is a high percentage yield important for a reaction?

Answer 9

Reduces cost

Doesn’t waste starting materials

Question 10

Why is a high atom economy desirable?

Answer 10

Reduces the production of unwanted products
Makes the process more sustainable
Maximises profit

Question 11

How are soluble salts made?

Answer 11

Titration - Alkali added to acid until it is just neutralised
Water evaporated

Question 12

Why is a compromise temperature sometimes used for reversible reactions which are exothermic in the forward direction?

Answer 12

A low temperature would give a high yield

However, a low temperature would give a slow rate of reaction.

Question 13

Why does a powder react faster than a lump of solid?

Answer 13

Powder has a greater surface area

Greater frequency of collisions between reactant particles

Question 14

What effect does a catalyst have on reversible reactions?

Answer 14

It increases the rate of the forward and backwards reactions

It doesn’t affect the position of equilibrium

Question 15

What are the disadvantages of using fuel cells?

Answer 15

Contain poisonous catalysts

Pollution is caused by the burning of fossil fuels when making the raw materials for the fuel cell

Question 16

What are the disadvantages of using fuel cells?

Answer 16

Contain poisonous catalysts

Pollution is caused by the burning of fossil fuels when making the raw materials for the fuel cell

Question 17

Why is a batch process used to make drugs but a continuous process used to make fertilisers?

Answer 17

Drugs are needed in small amounts

Fertilisers are used in large amounts

Question 18

Why is it important that air pollution is controlled?

Answer 18

Prevent harm to living organisms

Protect buildings

Question 19

Explain one advantage and one problem of recycling copper

Answer 19

Saves resources because the ore does not have to be extracted But, copper has to be sorted from other metals

Question 20

Why is reinforced steel a better construction material than normal concrete?

Answer 20

Steel is strong under tension, whereas concrete is strong under compression

Steel is more flexible

Question 21

What are the advantages of using aluminium rather than steel in car construction?

Answer 21

Aluminium is less dense

Aluminium does not corrode

Question 22

What is a hydrocarbon?

Answer 22

A compound that contains only hydrogen and carbon

Question 23

What is meant by a saturated compound?

Answer 23

All carbon-carbon bonds are single bonds

Question 24

What is meant by an unsaturated hydrocarbon?

Answer 24

Contains carbon-carbon double bonds

Question 25

Describe a chemical test for unsaturated fats

Answer 25

Add bromine water

Goes from orange to colourless

Question 26

Why can hydrocarbons be separated by fractional distillation?

Answer 26

Larger hydrocarbon molecules have stronger intermolecular forces

This means they have higher boiling points

Question 27

What political problems are associated with oil production?

Answer 27

UK is dependent on oil from other countries

Future supplies are not secure because wars happens

Question 28

What does non-renewable mean?

Answer 28

It is made slower than it is used up

Question 29

What is the test for an unsaturated hydrocarbon?

Answer 29

Bromine water

Changes from orange to colourless

Question 30

How do fertilisers increase crop yield?

Answer 30

Replaces essential elements
Nitrogen used to make plant protein
Phosphorous used to make ATP

Question 31

What are the benefits and disadvantages of fertilisers?

Answer 31

World population is rising so we need to produce more food

Water supplies become polluted

Question 32

Why is it important that fertilisers are soluble in water?

Answer 32

So they can be absorbed by the plant

Question 33

Why is water filtered before it is used for drinking?

Answer 33

To remove insoluble substances

Question 34

Why is water chlorinated before it is used for drinking?

Answer 34

To kill microbes

Question 35

What is a disadvantage of using distillation to purify water?

Answer 35

Large amounts of energy are needed

Question 36

How can rusting be prevented?

Answer 36

Painting, alloying, galvanising or sacrificial protection

Question 37

How does galvanising work?

Answer 37

Zinc acts a barrier for the water and oxygen

Zinc is a sacrificial metal as it loses electrons more readily