Oxford Revise AQA GCSE Combined Science Foundation | Chapter C11 answers

Question

Answers

Extra information

Mark

AO / Specification reference

01.1

top AL: short hydrocarbons out

middle AL: crude oil in

bottom AL: long hydrocarbons out

1

1

1

AO1

5.7.1.2

01.2

boiling

lower

1

1

AO1

5.7.1.2

01.3

diesel – car engine fuel

kerosene – aircraft fuel

residue – making roads

one mark for one correct

two marks for all correct

2

AO1

5.7.1.2

02.1

one from:

• lubricants
• solvents
• polymers
• detergents
• vehicle fuel
• feedstock (for other substances)
• petrol

must specify vehicle fuel

1

AO1

5.7.1.2

02.1

from top:

ethane

butane

1

1

AO1

5.7.1.1

02.2

C₂₂H₄₆

1

AO2

5.7.1.1

02.3

decane has a lower flammability, higher boiling pint, and higher viscosity

1

AO1

5.7.1.3

03.1

Ethane

1

AO2

5.7.1.1

03.2

C₃H₈

ten

C₂₀H₄₂

one mark for both cells completed

1

1

1

AO2

5.7.1.1

03.3

ethane

1

AO1

5.7.1.1

03.4

2 C atoms and 5 H atoms are added to chain

2 H atoms attached to 1 C atom and 3 H atoms added to end C atom

one mark for correct number of carbons and hydrogens

one mark for correct bonds

2

AO2

5.7.1.1

04.1

alkenes have (at least one) carbon–carbon double bond/alkenes are unsaturated

accept reverse argument for alkanes

1

AO1

5.7.1.4

04.2

brown to colourless/decolourises

‘clear’ does not gain any marks

1

AO1

5.7.1.4

04.3

C₁₁H₂₂

C₁₅H₃₀

C₄H₈

1

1

1

AO2

5.7.1.4

04.4

cracking

allow thermal decomposition

1

AO1

5.7.1.4

04.5

two from:

• ethene has a lower boiling point
• ethene has a lower meting point
• ethene is more flammable
• ethene has lower viscosity/is more runny/is a gas and is a liquid/solid

because pentacontene has a greater molecular size

for this section, award one mark for each correct point up to a maximum of two points

accept reverse argument for pentacontene

2

1

AO2

5.7.1.3

05.1

remains of ancient biomass/plankton

that was buried in the mud

1

AO1

5.7.1.1

05.2

evaporation

condensation

1

1

AO1

5.7.1.2

05.3

Level 3: Four or more correct uses are given. The writing is clear and coherent.

5-6

AO1

5.7.1.2

Level 2: Three correct uses are given. The writing is reasonably clear, but not well-organised.

3-4

Level 1: One or two correct uses are given. The writing lacks clarity and organisation.

1-2

No relevant content.

0

Indicative content:

• fuels, for example diesel, petrol, kerosene, liquefied petroleum gases
• raw materials for solvents
• raw materials for lubricants
• raw materials for polymers
• raw materials for detergents

06.1

a mixture of different length hydrocarbons

1

AO1

5.7.1.1

06.2

similar length hydrocarbon chains

1

AO1

5.7.1.2

06.3

boiling point

1

AO1

5.7.1.2

06.4

three from:

• fuel or named example (petrol, diesel, kerosene, LPG)
• solvents
• lubricants
• polymers
• detergents

one mark for each correct answer up to maximum of three marks

3

AO1

5.7.1.2

06.5

Level 3: Fully detailed description that gives evaporation/vaporisation of crude oil and where each fraction condenses. Explains why the fractions condense at three different locations in the column.

5-6

AO1

5.7.1.2

Level 2: Description of the evaporation and condensation of the three fractions, but no explanation given.

3-4

Level 1: Identify that fractions condense at different points in the column.

1-2

No relevant content.

0

Indicative content:

• crude oil vaporised
• passed into fractionating column
• fractionating column is hotter at the bottom and cools up the column
• residue condenses at the bottom of the column
• as hydrocarbons have the highest boiling points
• because they are made of the longest hydrocarbon chains
• diesel and petrol travel up the column.
• diesel condenses when it reaches its boiling point
• diesel has higher boiling point than petrol as longer hydrocarbon chains, but lower boiling point than residue as shorter hydrocarbon chain
• petrol travels furthest up the column
• as it has shortest hydrocarbon chain
• condense when it reaches its boiling point
• all three tapped off as liquids

07.1

C₆H₁₂

1

AO2

5.7.1.4

07.2

C₁₀H₂₂

allow error carried forward from question 07.1 if answer given is an alkane

1

AO2

5.7.1.4

07.3

catalytic

steam

1

1

5.7.1.4

07.4

short hydrocarbons are more useful than long hydrocarbons (or better fuels/greater demand for short hydrocarbons)

but not enough short hydrocarbons come from fractional distillation

1

1

AO1

5.7.1.4

07.5

mix with bromine water

bromine water is brown/orange

alkene will turn bromine water (back to) colourless

‘clear’ does not gain any marks

1

1

1

AO1

5.7.1.4

07.6

diesel shows an increase from 12 billion to 30 billion

petrol shows a decrease from 32 billion to 18 billion

accept +/- 2 for each mark

1

1

07.7

one from:

• less diesel fractions cracked to produce petrol
• increase in the amount of fractions cracked to produce diesel then
• decrease in the amount of fractions cracked to produce petrol

1

AO3

5.7.1.4

08.1

both require heat

In catalytic cracking, the vapour is passed over a hot catalyst.

In steam cracking, the vapour is mixed with steam before heating.

1

1

1

AO1

5.7.1.4

08.2

C₁₀H₂₂ → C₆H₁₄ + 2C₂H₄

1

AO2

5.7.1.1

08.3

to make more smaller alkane molecules for fuels

to make alkenes to produce polymers/other chemicals

1

1

AO1

5.7.1.4

09.1

length

lowest

shortest

viscous

longest

answers must be in this order

1

1

1

1

1

AO1

AO2

5.7.1.3

09.2

methane

1

AO3

5.7.1.3

09.3

decane: -30 °C

icosane: 36 °C

methane: -182 °C

pentadecane: 17 °C

one mark for one correct, two marks for two correct, three marks for all correct

3

AO3

5.7.1.3

09.4

oxygen

carbon dioxide + water

in either order

1

1

AO2

5.7.1.3

10.1

compound that contains only carbon atoms and hydrogen atoms

1

AO1

5.7.1.1

10.2

propane

1

AO1

5.7.1.1

10.3

5 C atoms and 12 H atoms are drawn

first and last C atoms in chain are attached to 3 H atoms and 1 C atom

middle 3 C atoms are attached to 2 H atoms and 2 C atoms

one mark for carbons and hydrogens

one mark for bonds

2

AO2

5.7.1.1