3.1 Density [Should Do]

Look at the densities of these materials:

pine wood 0.41 g/cm³

polycarbonate 1.2 g/cm³

polyethene 0.95 g/cm³

water 1.0 g/cm³

Which of these materials will sink in water?

• pine wood

• polycarbonate

• polyethene

Which is the equation for density?

• Density = mass x volume

A block of aluminium has a volume of 5.0 cm³ and a mass of 13.5 g. Calculate the density of the aluminium. Give your answer in g/cm³.

• 2.7

• 0.37

• 67.5

• 6.75

The block of wood in the diagram has a mass of 59 g. Calculate the density of the wood.

• 7.38

• 0.82

• 2.46

• 1.22

Silver has a density of 10.5 g/cm³ . Calculate the mass of silver that has a volume of 20 cm³.

• 1.90 g

• 0.525 g

• 210 g

Lead has a density of 11.3 g/cm³.

Calculate the volume of lead that has a mass of 6.0 g.

• 0.53 cm³

• 1.88 cm³

• 67.8 cm³

The irregular rock in the diagram has a mass of 65 g.

Calculate the density of the rock. (1 ml = 1 cm³)

• 2.6 g/cm³

• 0.38 g/cm³

• 16.25 g/cm³

The densities of diesel, water and gasoline are 860, 1000 and 725 in kg/m³ respectively.

So, A is ​ (a)   , B is ​ (b)   and C is ​ (c)   .

• water
• diesel
• gasoline

What is the property of the gas in balloon needed to make the balloon float in air?

Choose 2 answers.

• The gas must be less dense than air.

• The average density of the balloon, the string and the gas is less than that of air.

• The balloon must exceed a certain minimum size.

• The temperature of the surroundings must not be too law.

It is cooler in the early morning and late evening, so the surrounding air will be ​ (a)   ; the difference in density between the hot air balloon and the surrounding air will be ​ (b)   ; the hot air balloon will float more ​ (c)   .

• denser
• greater
• easily
• less dense
• smaller
• difficult