A B B 1 C I Alkali Ii Neutralisation Iii Sodium Chloride

Answers / Marks
1 / a B
b 1
c i alkali
ii neutralisation
iii sodium chloride / 1
1
1
1
1
2 / a A white precipitate or a white solid.
b lead nitrate + sodium chloride → lead chloride + sodium nitrate (reactants for one mark, products for one mark)
c Add sodium chloride or any other soluble salt that will give a precipitate with lead ions or a named alkali; allow to settle or filter. / 1
2
2
3 / There is a clear and detailed scientific description of how to prepare copper(ii) sulfate solution from copper(ii) oxide and dilute sulfuric acid and how to obtain crystals from the solution with five or six points from the examples given. The answer shows almost faultless spelling, punctuation and grammar. It is coherent and in an organised, logical sequence. It contains a range of appropriate and relevant specialist terms used accurately.
There is a scientific description of the preparation of copper(ii) sulfate with three or four points from the examples given. There are some errors in spelling, punctuation and grammar. The answer has some structure and organisation. The use of specialist terms has been attempted but not always accurately.
There is a brief description of the reaction of copper(ii) oxide with an acid or of crystallisation of a solution of copper(ii) sulfate with one or two points from the examples given. The spelling, punctuation and grammar are very weak. The answer is poorly organised with almost no specialist terms and/or their use demonstrating a general lack of understanding of their meaning.
No relevant content.
Examples of the chemistry points made in the response:
• Use dilute sulfuric acid.
• Place acid in a beaker.
• Warm the acid.
• Add copper(ii) oxide.
• In small amounts.
• Until in excess or there is no further reaction.
• Filter (to remove excess copper(ii) oxide).
• Heat filtrate/solution to evaporate some water.
• Allow solution to cool and crystallise or allow to evaporate slowly at room temperature.
• Remove/filter crystals from remaining solution. / 5-6
3-4
1-2
0
4 / a Two from: ions can move in solution; opposite charges attract; silver ions are positive and spoon is negative.
b gaining an electron
c Any sensible suggestion – e.g. better appearance; less toxic; less likely to corrode; less expensive than solid silver. / 2
2
1
5 / a i Sensible suggestion – e.g. high melting point; strong; can be shaped; holds (hot) liquid, does not react with liquid (magnesium chloride/magnesium); low cost; at high temperature carbon electrode would burn with oxygen from the air to produce carbon dioxide.
ii Sensible suggestion – e.g. does not react with chlorine; high melting point; low cost (but do not accept if low cost already allowed in i).
b i Less heat/energy needed or lower cost of energy (accept less heat lost).
ii Less fossil fuel burned (for heat/energy) so less pollution; less global warming; resources conserved; less mining (must be linked) or less thermal; heat pollution.
c i Mg2+ + 2e– → Mg
ii Cl– → Cl2 + 2e– / 1
1
1
1
1
1