1. 1
   An electrician compares copper wire, a metal, with rubber and plastic insulation, non-metals, when wiring a building, relying on the copper to carry electric current safely.

   (a)

   Why is copper, a metal, used as an electrical wire rather than a non-metal such as sulfur?

   [1 mark]

   • AMetals are poor conductors of electricity
   • BMetals are good conductors of electricity
   • CNon-metals are always ductile
   • DNon-metals have higher electrical conductivity than metals

   (b)

   Which property allows copper to be drawn out into thin wires?

   [1 mark]

   • ABrittleness
   • BHigh electrical resistance
   • CLow melting point
   • DDuctility

   (c)

   State two other general physical properties, besides electrical conductivity and ductility, in which metals such as copper typically differ from non-metals.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A blacksmith heats an iron bar and hammers it into a horseshoe shape, then quenches it in cold water. He compares this with a lump of sulfur, which shatters when hit with a hammer.

   (a)

   Which property of iron allows the blacksmith to hammer it into a new shape without it breaking?

   [1 mark]

   • AMalleability
   • BLow density
   • CBrittleness
   • DPoor thermal conductivity

   (b)

   Why does the sulfur shatter when hit with a hammer, unlike the iron?

   [1 mark]

   • ASulfur is malleable
   • BSulfur has a higher melting point than iron
   • CSulfur is a non-metal and is brittle
   • DSulfur is a good conductor of heat

   (c)

   Explain, in terms of general physical properties, why the iron bar can be hammered into shape but the sulfur cannot.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A chemistry teacher demonstrates three reactions to a class: adding magnesium ribbon to dilute hydrochloric acid, adding sodium to cold water, and passing steam over heated iron filings.

   (a)

   Describe what would be observed when magnesium reacts with dilute hydrochloric acid, and name the gas produced.

   [3 marks]

   (b)

   Compare the reaction of sodium with cold water to the reaction of iron with steam, describing the products formed in each case and how the reactivity of the two metals differs.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   An engineer is choosing materials for a new bridge, comparing steel (mainly iron) with aluminium and considering how each metal will behave when exposed to rain, damp air and occasional road de-icing chemicals over many years.

   (a)

   Describe the general physical properties of metals, such as those used in the bridge, that make them suitable for construction, comparing them with typical non-metal properties.

   [6 marks]

   (b)

   Explain, using ideas about chemical reactivity, what would happen if the iron and steel in the bridge were exposed to oxygen, damp air and dilute acidic pollutants over time, and suggest how this compares with a less reactive metal.

   [6 marks]

   Total for question 4: 12 marks

End of questions