Questions Corrections 2022

Question 1

Suggest why poly(butene) insulation must be removed from scrap copper wire before the copper is recycled

Answer 1

Otherwise the copper produced would be impure

Question 2

Describe how scrap copper wire can be recycled to make new copper water pipes

Answer 2

Wire heated until copper melts
Reformed into pipes

Question 3

Suggest two reasons why recycling scrap copper is more sustainable than extracting copper from copper ores

Answer 3

Uses less energy
Produces less waste

Question 4

A solution can be added to copper sulfate solution to show show the presence of copper ions
Name the solution and the result of the test

Answer 4

Sodium hydroxide solution
Blue precipitate

Question 5

Describe one test to show the presence of sulfate ions in copper sulfate solution

Answer 5

Add acidified barium chloride solution
White precipitate

Question 6

Suggest why the test tube and contents were heated until the mass did not change

Answer 6

So that the reaction was complete

Question 7

Name two materials produced from feedstock for the petrochemical industry

Answer 7

Solvents
Detergents

Question 8

Explain why sulfur impurities are removed before petrol is burned in car engines

Answer 8

As sulfur dioxide is produced
Which causes acid rain

Question 9

Justify the students prediction that heavy fuel oil is more viscous than kerosene

Answer 9

As molecular size increases viscosity increases
Heavy fuel oil has larger molecules than kerosene

Question 10

Three conditions for cracking

Answer 10

High temperature
Catalyst
Steam

Question 11

What type of hydrocarbon molecules turn bromine water colourless

Answer 11

Alkenes

Question 12

Explain why the concentration of sodium and chloride ions are unchanged through filtration

Answer 12

The ions pass through the filter
As the ions are in solution

Question 13

Explain why the ground water requires exposure to UV before the water is safe to drink

Answer 13

Contains microbes which are harmful to humans
So water is sterilised

Question 14

Suggest what a chemical company means by ‘pure’ water

Answer 14

The water is in its natural state

Question 15

Describe the test for chlorine gas

Answer 15

Damp litmus paper
Paper is bleached

Question 16

Give the sources of nitrogen and of the hydrogen used in the Haber process

Answer 16

Nitrogen= air
Hydrogen = natural gas

Question 17

Explain how ammonia produced is separated from the unreacted nitrogen and hydrogen

Answer 17

Mixture is cooled
So only ammonia liquefies

Question 18

Sulfur is produced in a reaction explain why the mixture became cloudy

Answer 18

Sulfur is a precipitate

Question 19

Explain why the mean rate of reaction decreases from 0-60 seconds in terms of concentration

Answer 19

Rate decreases
because concentration of reactants decreases