A-LevelChemistryChemical bonding9701/21 · May/June 2017 · Q215 Marks

Structure and bonding can be used to explain many of the properties of substances.

(a)Copper, ice, silicon(IV) oxide, iodine and sodium chloride are all crystalline solids. Complete the table with: - the name of a type of bonding found in each crystalline solid, - the type of lattice structure for each crystalline solid. crystalline solid type of bonding type of lattice structure copper ice silicon(IV) oxide iodine sodium chloride[5]
(b)(i)Name the strongest type of intermolecular force in ice.[1]
(b)(ii)Draw a fully labelled diagram of two water molecules in ice, showing the force in (i) and how it forms.[3]
(c)(i)The graph represents how the temperature of a sample of copper (melting point 1085°C) changes as it is gradually cooled from 1200 °C. [Figure 2.1] Identify the state(s) of matter present during each stage of the process shown in the graph. X Y Z[2]
(c)(ii)State what is happening to the energy and movement of the particles in the copper during stage X.[2]
(c)(iii)Explain why the temperature stays constant at T₁ during stage Y.[2]

Mark scheme

Marking points from the official mark scheme (May/June 2017). The mark or mark type is shown in brackets.

[1] copper metallic giant/metallic
[1] ice covalent OR hydrogen(-bonding) / H(-bonding) hydrogen-bonded / simple / molecular
[1] silicon(IV) oxide covalent giant (molecular) / macromolecular
[1] iodine covalent simple / molecular
[1] sodium chloride ionic giant/ionic
[1] hydrogen bonding
[1] H-bond between O and H of different molecules
[1] minimum three partial charges (in a row) over two H₂O molecules, i.e.: either δ⁻O—Hδ⁺ – – – – δ⁻O or Hδ⁺ – – – – δ⁻O—Hδ⁺
[1] lone pair of electrons on O of H-bond, in line with H-bond
[1] X = liquid AND Z = solid
[1] Y = liquid and solid OR 'liquid / solid' OR 'liquid OR solid'
[1] (kinetic) energy reducing
[1] motion slowing (owtte)
[1] energy given out / released forming bonds / forming bonds exothermic
[1] compensates for / counteracts heat loss / cooling (owtte)

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