Density Exercises

The lava lamp shown on the right works by changes to the density of the oil inside the water.

Explain how these density changes come about.
Compare the density of the oil and the water as the oil rises.
The density of a sample of salty water is 1.1g/cm3 . What will 30cm3 of this salty water weigh?
The cube on the right is made of a pure unknown substance "X". If it weighs 132 grams calculate its density?

The densities of 5 liquid substances are shown below.

Substance "F" = 3.8 g/cm3
Substance "A" = 1.4 g/cm3
Substance "J" = 1.1 g/cm3
Substance "H" = 1.9 g/cm3
Substance "K" = 4.2 g/cm3
Indicate True or False for each statement.

Statement
True
 False
Substance "X" will float on a layer of substance "K"
Substance "A" will float on a layer of substance "H"
30cm3 of substance "K" will weigh 110 grams.
A sample of substance "J" weighs 8.8 grams and its volume is 8cm3
20cm3 of substance "F" is mixed with 20cm3 of substance "A" to give a 40cm3 solution with a density of 2.6g/cm3

Which has the greatest density 5kg of lead or 22 kg of aluminium?