Examiner reports

Question 1

Describe how ethanol is produced from sugar solution.
Give the name of this process.

Answer 1

fermentation
add yeast
anaerobic (conditions)

Question 2

Name the gas produced when sodium is added to ethanol.

Answer 2

Hydrogen.

Question 3

Suggest why ammonia condenses but the other gases do not.

Answer 3

ammonia has a higher boiling
point

Question 4

What type of substance reacts with methanol to produce methanoic acid?

Answer 4

oxidising (agent).

Question 5

Why are scientists not certain about the percentage of each gas in the Earth’s early atmosphere?

Answer 5

• occurred 4.6 billion years ago

Question 6

Explain how carbon monoxide is produced when petrol is burned in car engines.

Answer 6

incomplete combustion
insufficient oxygen supply

Question 7

Give two effects of atmospheric pollution which are reduced by using catalytic converters

Answer 7

acid rain
* respiratory problems

Question 8

Suggest why a catalyst is used in this industrial process.

Answer 8

less energy is needed.

Question 9

The chemist sets up a paper chromatography experiment in order to check for impurities in the paint.
Describe how the chemist could use chromatography to calculate the Rf value of indigo blue.

Answer 9

● draw (pencil) start line on (chromatography)
paper
● place spot of food colouring on start line
● place solvent in beaker/ place paper in
● solvent is below start line
● use a lid
● wait for solvent to travel up the paper
● mark solvent front.
divide the distance travelled by the component by the distance travelled by the solvent.

Question 10

A water company wants to test the amount of solids dissolved in their water.
Suggest a method of how they might do this

Answer 10

● weigh (evaporating) basin
● add measured volume of water
● weigh (evaporating) basin and water
● heat to evaporate water
● reweigh
● repeat heating until constant mass obtained
● subtract mass of (evaporating) basin from mass

Question 11

Oil contains carbon and some sulfur.
When oil is burned, the products of combustion may be released into the atmosphere.
Explain the environmental effects of releasing these products of combustion into the atmosphere.

Answer 11

sulfur dioxide produced
* (which causes) acid rain
* (so) damage to buildings / statues
* carbon / soot produced
* (which are) particulates
* (which cause) global dimming

Question 12

Suggest three reasons why recycling scrap copper is a more sustainable way of
obtaining copper than processing copper ores.

Answer 12

recycling conserves copper ores
* recycling uses less energy
* recycling reduces waste