Oxford Revise AQA GCSE Combined Science Foundation | Chapter C10 answers

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C10: Equilibrium

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Mark

AO / Specification reference

01.1

reactants, products

⇌

products, reactants

1

1

1

AO1

5.6.2.1

01.2

combustion of paper

1

AO1

5.6.2.1

01.3

(dynamic) equilibrium

1

AO1

5.6.2.3

01.4

endothermic

1

AO1

5.6.2.3

02.1

ammonium chloride

1

AO3

5.6.2.1

02.2

reaction is reversible

therefore, as ammonia and hydrogen chloride gases cool, they react to form ammonium chloride

1

1

1

AO2

5.6.2.1

02.3

crystals turn blue/hydrated copper(II) sulfate is made

1

AO3

5.6.2.1

02.4

test tube would warm up

1

AO3

5.6.2.2

03.1

reaction is reversible

1

AO2

5.6.2.2

03.2

white crystals turn blue

test tube gets warm

1

1

AO3

5.6.2.2

03.3

ionic

1

AO2

5.2.1.1

03.4

one from:

  • fingers don’t get burnt
  • wear goggles to protect eyes
  • stand back to avoid spitting from basin
  • use heat proof mat under Bunsen burner
  • gloves

1

AO3

5.6.2.2

04.1

endothermic

1

AO1

5.6.1.1

04.2

A and B

1

AO1

5.6.1.1

04.3

N2 + 3H2 ⇌ 2NH3

1

AO2

5.1.1.1

04.4

endothermic

1

AO1

5.6.1.2

04.5

no

1

AO2

5.6.1.2

05.1

reversible

accept equilibrium

1

AO1

5.6.2.1

05.2

H2 and I2 react together to make HI at the same rate that HI reacts to form H2 and I2

1

AO2

5.6.2.3

05.3

when H2 and I2 react to form HI energy is transferred from the surroundings/the system takes in energy from the surroundings

ignore exothermic

the energy transfers need to be explained

1

AO1

5.6.2.1

05.4

increase pressure

increased frequency of collisions

or

increase temperature

more frequent collisions with activation energy

1

1

or

1

1

AO2

5.6.1.3

06.1

g, g, s

1

AO2

5.2.2.2

06.2

the products of the reaction can react to produce the original reactants

1

AO1

5.6.2.1

06.3

(dynamic) equilibrium

1

AO1

5.6.1.3

07.1

exothermic

1

AO2

5.5.1.1

07.2

measure temperature increase/change of the surroundings

1

AO3

5.5.1.1

07.3

exothermic, endothermic

1

AO1

5.6.2.3

07.4

4 J

1

AO2

5.6.2.3

08.1

N2O4 ⇌ 2NO2

1

AO2

5.1.1.1

08.2

take in energy from the surroundings

1

AO1

5.5.1.1

08.3

more NO2 gas produced

1

AO3

5.6.2.3

08.4

prevents escape of reactants and

products/substances/gases

1

AO1

5.6.2.3

09.1

substances/water/steam/gas can escape from the apparatus

1

AO2

5.6.2.3

09.2

Bunsen burner

1

AO1

5.6.2.2

09.3

steam/water/water vapour

1

AO2

5.6.2.2

09.4

attach bung and delivery tube to test tube

feed delivery tube into beaker

in icy water

1

1

1

AO3

5.6.2.2

10.1

increase in temperature

crushing lump into powder

1

1

AO1

5.6.1.2

10.2

activation energy

1

AO1

5.5.1.2

10.3

reduce the number of acid particles/reactant particles in a given volume

less frequent collisions

lower rate of reaction

1

1

1

AO1

5.6.1.3

11.1

two from:

  • moves around on surface of water
  • fizzing
  • lilac/mauve/purple flame
  • if universal indicator has been added to the water, there is a colour change from green to purple/blue

one for each correct observation up to a maximum of two marks

2

AO1 – 2

4.1.2.5

11.2

reactivity with water increases as you go down the group

because the single electron in the outer shell is further away from the nucleus

accept shielding from more shells

1

1

AO1

5.1.2.5

11.3

eye goggles/handle with gloves/safety screen

accept any sensible suggestion

1

11.4

lithium hydroxide

hydrogen

1

1

AO1 – 2

4.1.2.5

4.4.1.2

11.5

no change

1

AO1 – 1

4.4.2.1
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