Step by step
The question
Question: find the density when the mass is 156 g and the volume is 12 cm³.
Mass 156 g, volume 12 cm³. Find the density.
1 Write the rule
The rule: density is the mass divided by the volume.
density = massvolume
Density tells us how much mass there is in 1 cm³.
So its unit is g per cm³.
density = the mass of 1 cm³
unit: g ÷ cm³ → g/cm³
2 Put the numbers in
The mass is 156.
The volume is 12.
density = 15612
3 Work it out
Careful!
The mass goes on the top.
The unit, g/cm³, shows it: g on the top.
Careful: not 12156 ✗
156 divided by 12 is 13.
156 ÷ 12 = 13
That is 13 g/cm³.
density = 13 g/cm³
So the density is 13 g/cm³.
4 Check
Let's check.
13 in each cm³, for 12 cm³: 13 times 12 is 156.
That is the mass.
So the answer is right!
13 g in each cm³: 13 × 12 = 156 g
Let's look back.
First: write the rule.
Then: put the numbers in.
Then: work it out.
Last: check.
Answer
density = 13 g/cm³