O-LevelChemistryMetals & Reactivity5070/21 · May/June 2020 · Q28 Marks

Part of the reactivity series is shown. calcium more reactive aluminium manganese zinc less reactive

(a)Predict the names of the products formed when manganese reacts with dilute hydrochloric acid.[1]
(b)A sample of manganese(II) carbonate, MnCO3, is heated strongly. Construct the equation for this reaction.[1]
(c)Powdered manganese is added to aqueous zinc sulfate to form aqueous manganese(II) sulfate, MnSO4· Construct an ionic equation, with state symbols, for this reaction.[2]
(d)Zinc powder, a reducing agent, is added to acidified aqueous potassium manganate(VII). Describe the colour change during this reaction.[1]
(e)(i)Aluminium is extracted by the electrolysis of aluminium oxide dissolved in molten cryolite. Write the electrode equation for the formation of aluminium atoms at the cathode.[1]
(e)(ii)Write the electrode equation for the formation of oxygen molecules at the anode.[1]
(f)State one advantage of recycling aluminium.[1]

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Mark scheme

Marking points from the official mark scheme (May/June 2020). The mark or mark type is shown in brackets.

[1] reacts to give hydrogen and manganese chloride
[1] MnCO3 → MnO + CO2
[2] Mn(s) + Zn2+(aq) → Mn2+(aq) + Zn(s) balanced (1) state symbols – dependent on correct formulae (1)
[1] purple to colourless
[1] Al3+ + 3e¯ → Al
[1] 2O2-→ O2 + 4e¯ / 2O²– – 4e¯ → O2
[1] saves natural resources / less environmental damage due to mining / saves energy

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