Properties and uses of some metals
3 marks · NormalAluminium is often used to make power transmission cables because it has a low density and is a good conductor of electricity. A section of cable is made of pure aluminium and has a mass of and a volume of .
Calculate the density of aluminium in . State one reason, based on its properties, why aluminium is chosen for this use.
Density = mass ÷ volume
Calculate the density of aluminium in .
State one property of aluminium that makes it suitable for use in power cables.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) 2.7 g/cm^3 · must show Correct formula, Correct working, Correct units
(b) Low density OR good conductor of electricity OR resists corrosion · must show Any one correct property relevant to use in power cables
Common mistakes: Incorrect division of mass and volume; Confusing mass for volume; Listing an unsuitable property like 'it is magnetic'
Show mark scheme and worked solution
Marking points
M1 (a) · 1 mark · Correctly substitutes values into the density formula or shows correct calculation step.
A1 (a) · 1 mark · Obtains correct value for density: 2.7 g/cm³, allow 2.7 to 2.8 due to rounding. (follow-through)
B1 (b) · 1 mark · States a relevant property of aluminium (e.g. low density, good conductor, or resists corrosion).
Worked solution
a) Use the formula: density = mass ÷ volume.
b) One property of aluminium making it suitable for power cables is its low density (it is lightweight), or it is a good conductor of electricity, or it resists corrosion.