Density: Formula and units
In a nutshell
Density is a measure of how heavy 1cm3 of a material is. Another way of saying this is that density is the mass per unit volume of a material. Every material has its own density.
Density formula
The density of a material is given as:
density=volumemass
Or, more simply:
D=VM
Units of density, mass and volume
Measurement
| Units
|
| Density
| kilograms per cubic metre (kg/m3), grams per cubic centimetre (g/cm3)
|
| Mass
| kilograms ( kg), grams ( g) |
| Volume
| cubic metres ( m3), cubic centimetres ( cm3) |
Solving density problems
To solve problems involving density, follow this procedure:
procedure
| 1.
| Identify what values you have and what variable you want to find.
|
| 2.
| Rearrange the density formula for the desired variable.
|
| 3.
| Substitute in known values.
|
| 4.
| Give the answer with the correct units.
|
Example 1
The density of gold is 19,300kg/m3. A bar of gold weighs 4,000kg. What is the volume of this bar to two decimal places?
From the given information, identify the density and the mass:
D=19,300kg/m3,M=4,000kg
Write down the density formula:
D=VM
Rearrange the density formula for volume:
V=DM
Substitute in the known values:
V=19300kg/m34000kg
Give the answer with the correct units:
V=0.207253886...m3
Round to two decimal places, like the question asks:
V=0.21m3, to two decimal places.
