O-LevelChemistryMetals & Reactivity5070/21 · Oct/Nov 2015 · Q410 Marks

Copper is a metal.

(a)Draw a labelled diagram to show the bonding in copper.[2]
(b)Explain why metals are malleable.[2]
(c)(i)Copper corrodes slowly in damp air. One of the corrosion products has the formula CuCO3.Cu(OH)2. Calculate the percentage by mass of copper in this compound.[2]
(c)(ii)How could you show that CuCO3.Cu(OH)2 contains carbonate ions?[2]
(d)Copper is oxidised by concentrated sulfuric acid. This redox reaction can be represented by equations A and B. A Cu → Cu2+ + 2e- B 4H+ + SO42- + 2e- → 2H2O + SO2 Which reaction, A or B, is oxidation and which is reduction? Explain your answer.[2]

Mark scheme

Marking points from the official mark scheme (Oct/Nov 2015). The mark or mark type is shown in brackets.

[2] A4 (a) positive ions in regular layers with a minimum of two layers of ions (1) electrons shown interspersed between the particles shown (1) + + + + positive ion e 0000 electron e e e e e + + + + Marks can be awarded from correct description in writing or from labelled diagram.
[2] (b) idea of layers of metal atoms/or ions (1) can slide over each other (when force applied) (1)
[2] (c) (i) correct Mᵣ of 128 or (2 × 64) as numerator of fraction OR correct Mᵣ (2 × 64) + 12 + (16 × 5) + (2 × 1) or 222 as denominator (1) percentage = 57.65/57.7 (1)
[2] (ii) add acid (1) gas evolved turns limewater milky (1)
[2] (d) A is oxidation because electrons are lost (1) B is reduction because electrons are gained (1)

On Oracle Prep you can write or photograph your own answer and have it marked by AI against this mark scheme, with feedback on what you missed.