Number 8

4 marks · Hard

A block of plastic has a mass of 2.4 kg and occupies a volume of 1500 cm³.

(a)

Convert the mass to grams (g).

[1 mark]

(b)

Work out the density of the plastic in g/cm³.

[2 marks]

(c)

Express your answer to part (b) in kg/m³.

[1 mark]

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) 2400 g

(b) 1.6 g/cm³

Common mistakes: Not converting mass to grams in part (b); Not multiplying by 1000 in part (c)

Show mark scheme and worked solution

Marking points

M1 (a) · 1 mark · Converts mass from kg to g correctly.

M2 (b) · 1 mark · Uses density = mass/volume with correct units (mass in grams, volume in cm³). (follow-through)

A1 (b) · 1 mark · Correctly calculates 1.6 g/cm³ (accept follow-through from part a). (follow-through)

A2 (c) · 1 mark · Correctly converts g/cm³ to kg/m³ by multiplying by 1000 (accept follow-through from part b). (follow-through)

Worked solution

a) 1 kg = 1000 g, so

b) Density = mass / volume:

c) To convert g/cm³ to kg/m³, multiply by 1000: