Paper 2 Practice questions

Question 1

Ethanol can be produced from ethene and steam
The reaction is exothermic
Explain how the conditions for this reaction should be chosen to produce the ethanol as economically as possible

Answer 1

Higher temperature will give higher rate
Due to more successful collisions
Higher pressure will induce higher rate
because more collisions
The use of a catalyst

Higher temperature will give lower yield
because the reaction is exothermic
High temp will use more energy so cost increase
finding a compromise between temperature, yield and pressure

Question 2

Compare ethene with ethane
Refer to:
Their structure and bonding
Their reactions

Answer 2

Structure and bonding:
Both are hydrocarbons
Both contain 2 carbons atoms
Ethene has 4 hydrogen atoms while ethane has 6
Both have covalent bonds
But ethene is unsaturated while ethane is saturated

Reactions:
Both reaction with oxygen in complete combustion reactions
To produce water and C02
Ethene is more reactive than ethane so can react with bromine
so can turn orange bromine water colourless
Ethene can undergo (addition) polymerisation

Question 3

A student adds a solution of ethanoic acid and zinc CARBONATE in a flask on a balance
Explain what happens to the mass of the flask during the reaction

Answer 3

Mass of flask decreases
Because carbon dioxide is produced
which escapes from the flask

Question 4

The rate of methanoic acid is greater then the rate of reaction of ethanoic acid
Explain why

Answer 4

Methanoic acid has a lower pH
So methanoic acid has a higher concentration of hydrogen ions
So there will be a higher rate of collisions

Question 5

Wine contains alcohol
a bottle of wine was left open in the air
After a few days it tasted of vinegar
Explain how oxidation causes the wine to taste of vinegar

Answer 5

Air contains oxygen which oxidises the ethanol to produce ethanoic acid

Question 6

Sand is heated with two other materials to create glass?
What two other materials?

Answer 6

Limestone
sodium carbonate

Question 7

Describe how a rate of reaction changes ( from a graph)

Answer 7

Usually rate will be greatest at the start
then rate decreases

Question 8

why is the rate of reaction greater when a higher conc of acid/alkali is used?

Answer 8

More particles in the same volume
so more particle collisions each second

Question 9

Why is chlorine added to filtered water to treat it?

Answer 9

To sterilise the water

Question 10

Calcium compounds produce an orange-red colour
The students method did not produce a distinct orange- red flame colour when using calcium iodide solution

Answer 10

the metal wire used was not dipped in HCL to remove any impurities/ other substances

Question 11

Explain how a furnace that burns copper sulphide could cause environmental pollution?

Answer 11

Sulfur from the copper will react with Oxygen causing sulfur oxide which can create acid rain

Question 12

Explain why the solution of ethanoic acid has a higher PH then the solution of hydrochloric acid?

Answer 12

Carboxylic acids known as ‘weak’ acids
ethanoic partially ionises
shown between dynamic equlibrium of ethanol and ethanoic acid

Question 13

what does volatile mean?

Answer 13

can easily turn into a gas

Question 14

The activation energy for a reaction between zinc and sulfuric acid is lowered if a solution containing metal ions is added.
What meta ion is most likely to be added?

Answer 14

Copper as TRANSITON METALS ARE CATALYSTS

Question 15

Petrol obtained from crude oil contains sulphur impurites
Explain why they should be removed before the petrol is burned in car engines

Answer 15

When the sulphur impurities are burned
they create sulphur dioxide
which creates acid rain

Question 16

Why did co2 decrease in the earth’s early atmosphere?

Answer 16

The co2 decreased was dissolved into the oceans
in the form of precipitates/sediments

Question 17

Natural gas is a fossil fuel
describe how deposits of natural gas were formed

Answer 17

Plankton/ marine organisms died
And covered by sediments
and subjected to high temp and pressure over millions of years

Question 18

Suggest 2 reasons why bitumen is not used as a fuel

Answer 18

Is to viscious
Not very volatile
Boiling point is too high

Question 19

Magnesium is fixed to steel ships
Explain how this prevents the steel from rusting

Answer 19

Mg is more reactive then steel so the Mg will errode before the steel

Question 20

Explain why aluminum window frames do not corrode after they are made

Answer 20

Aluminum has a coating of aluminum oxide
protects the metal from corrosion

Question 21

What is bioleaching?

Answer 21

bioleaching uses bacteria to produce leachate solutions that contain metal compounds

Question 22

Limewater is an aqueous solution of

Answer 22

calcium hydroxide

Question 23

explain why the increase in world population may have caused the increase in the concentration of carbon dioxide in the atmosphere?

Answer 23

more energy required
so more fossils fuels burnt which emit c02

Question 24

Describe what is meant by bioleaching?

Answer 24

Using bacteria
to produce leachate solution
to extract metal from its compound

Question 25

explain how a manganese dioxide CATALYST increases the rate of decomposition of hydrogen peroxide?

Answer 25

catalysts provide a different reaction pathway
which means activation energy is lowered.

Question 26

how is potassium chloride found in the earth?

Answer 26

through mining/quarrying