1. 1
   An electricity company uses long aluminium cables strung between pylons to carry electricity across the countryside, because aluminium conducts electricity very well and is relatively light. During installation, workers also need to bend the cables around the pylon supports without them snapping.

   (a)

   Which statement correctly describes a general property shared by metals such as aluminium?

   [1 mark]

   • AMetals conduct electricity only when heated to very high temperatures
   • BMetals are generally poor conductors of heat and electricity
   • CMetals are generally good conductors of both heat and electricity
   • DMetals conduct electricity but never conduct heat

   (b)

   During installation, workers bend the aluminium cables around the pylon supports without them snapping. Which statement explains why metals such as aluminium can generally be bent into shape?

   [1 mark]

   • ALayers of atoms within the metal are able to slide over each other while remaining held together
   • BMetal atoms are only loosely connected and can be pulled apart easily
   • CMetals contain gaps between atoms that allow them to be reshaped freely
   • DMetals become liquid briefly when bent, then solidify again

   (c)

   Explain why aluminium is a suitable material for both carrying electricity over long distances and being bent into shape around pylon supports during installation.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A goldsmith hammers a small lump of gold into an extremely thin sheet of gold leaf, so thin that light can almost pass through it, without the gold cracking or breaking apart. The goldsmith's workshop also uses copper wiring, which conducts heat away from a soldering iron very effectively.

   (a)

   Which statement explains why gold can be hammered into such a thin sheet?

   [1 mark]

   • AThe layers of atoms in gold can slide over each other under the force of hammering, allowing the metal to be flattened without breaking
   • BGold atoms dissolve into each other when hammered, forming a thinner liquid layer
   • CGold contains no chemical bonds between its atoms, so it separates easily when hammered
   • DGold becomes a gas when hammered thin enough to let light through

   (b)

   The goldsmith's workshop uses copper wiring, which conducts heat away from a soldering iron very effectively, preventing the handle from overheating. Which statement correctly describes this property of copper?

   [1 mark]

   • ACopper, like most metals, is a good conductor of heat, allowing thermal energy to spread through it and away from a hot point quickly
   • BCopper is a poor conductor of heat, which is why the handle does not overheat
   • CCopper only conducts heat when it is melted
   • DCopper absorbs heat permanently and never releases it

   (c)

   Explain why gold can be hammered into extremely thin sheets without cracking, and why copper is a good choice of material for conducting heat away from a hot soldering iron.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A student compares a metal rod (iron) with a non-metal rod (sulfur) of the same size. She connects each rod in turn to a circuit with a battery and ammeter, and also tries to bend each rod slightly. The iron conducts electricity and bends slightly without breaking; the sulfur does not conduct and snaps immediately when bent.

   (a)

   Explain, referring to general properties of metals and non-metals, why the two rods behave so differently.

   [3 marks]

   (b)

   The student also touches each rod after it has been sitting in a warm room and notices that the iron rod feels warmer to the touch more quickly than the sulfur rod when both are placed briefly on a hot surface. Explain this observation, and describe how the general physical properties of metals like iron make them useful for a wide range of everyday and industrial applications.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A construction engineer is choosing materials for a new road bridge and selects steel (an alloy of iron) for the main support beams, partly because it can be rolled and shaped into girders during manufacturing and partly because it must safely carry electrical earthing currents from lightning strikes. The engineer also considers using a brittle, non-metal ceramic material for a small non-load-bearing decorative panel on the bridge.

   (a)

   Describe, referring to the general properties of metals, why steel is well suited to both of these requirements.

   [6 marks]

   (b)

   The engineer also considers using a brittle, non-metal ceramic material for a small non-load-bearing decorative panel on the bridge, but decides it would be completely unsuitable for the main support beams. Explain, referring to the general properties of metals compared with non-metals, why a ceramic material would be unsuitable for the main support beams of the bridge, even though it might be acceptable for a small decorative panel that carries no load.

   [6 marks]

   Total for question 4: 12 marks

End of questions