O-LevelChemistryMetals & Reactivity5070/22 · May/June 2014 · Q58 Marks

Haematite, limestone and coke are heated together in a blast furnace in the manufacture of iron.

(a)State why each of the following compounds are needed in a blast furnace. haematite limestone coke [3][3]
(b)Iron has a high melting point because it has strong metallic bonding. Describe, using a labelled diagram, metallic bonding. .[2][2]
(c)When iron is made into the alloy steel, the properties of iron are changed. High carbon steels are stronger than iron but are brittle. State a property of low carbon steels. .[1][1]
(d)(i)When magnesium powder is added to aqueous iron(II) sulfate, the following reaction occurs. Mg(s) + Fe2+(aq) → Mg2+(aq) + Fe(s) Explain, using electron transfer, why iron(II) ions are reduced in this reaction. .[1][1]
(d)(ii)What would you observe in this reaction? .[1][1]

Mark scheme

Marking points from the official mark scheme (May/June 2014). The mark or mark type is shown in brackets.

[1] A5 (a) Haematite – is iron ore / contains the iron / is reduced to form iron (1)
[1] (a) Limestone - (decomposes to) form calcium oxide which removes impurities (1) ALLOW: lime (in place of calcium oxide)
[1] (a) Coke - forms carbon monoxide / reduces the iron ore (1)
[1] (b) Positive ions in regular layers (1) NOTE: 2 layers of ions is the minimum required in a diagram.
[1] (b) Electrons shown interspersed between the particles drawn (1) NOTE: Marks can be scored from correct description in writing or from a labelled diagram.
[1] (c) Softer / more malleable / more ductile (1)
[1] (d) (i) Iron(II) ions gain electrons / iron ions gain electrons / it gains electrons (1)
[1] (d) (ii) Green solution becomes paler / green solution fades / green solution becomes colourless / magnesium becomes coated with a dark solid (1)

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