2018 Paper 2

Question 1

What colour flames do sodium ions produce

Answer 1

Yellow

Question 2

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

Answer 2

Fermentation. Add yeast. Need anaerobic and warm ( NOT HIGH TEMP) conditions

Question 3

Sodium thiosulfate solution reacts with dilute hydrochloric acid. The solution becomes cloudy as the reaction takes place. Explain why it becomes cloudy

Answer 3

Sulfur is formed as a precipitate

Question 4

Suggest why it is more sustainable to use a mixture of poly(propene) and wool for carpets instead of just one

Answer 4

Poly (propene) comes from a non renewable source
Poly propene is not bio degradable
To create wool you need a whole area of land wich could be used instead to cultivate crops and grow food

Question 5

Give the approximate temperature and pressure used to produce ammonia in a reactor

Answer 5

Temperature: 450
Pressure: 200 atm (atmospheres)

Question 6

Explain the changes in the level of carbon dioxide and oxygen from the earths early atmosphere

Answer 6

Carbon dioxide has decreased. It’s thought to have dissolved in the oceans. Carbon is locked up in sedimentary rocks and fossil fuels. oxygen has increased due to algae and plants evolving and photosynthesising to produce oxygen

Question 7

Name the small molecule lost after monomers join together

Answer 7

Water

Question 8

How does a catalyst increase rate of reaction

Answer 8

Provides a different pathway which has a lower activation energy

Question 9

Suggest the effect of using the catalyst on the equilibrium yield of methanol.

Answer 9

no effect

Question 10

Melamine is a polymer used to make non-disposable cups. Melamine does not melt when it is heated.
Explain why.

Answer 10

melamine is a) thermosetting (polymer) (which) contains crosslinks / bonds (between polymer chains)