What is density?

Density measures the compactness in molecular arrangement in any substance which determines how heavy or light any substance is.

The density formula is #"density"# = #"mass"/"volume"#. Mass units are most commonly grams or kilograms. Volume units are most commonly cubic centimeters (#"cm"^3#), cubic meters (#"m"^3#), or millileters (mL).

Examples of density include the following:

The density of water at #"4"^"o""C"# can be written as #"1.000g/cm"^3#, #"1.000g/mL"#, #"1000Kg/m"^3#, and #"1.000kg/L"#.

The density of iron at #"0"^"o""C"# is #"7.874g/cm"^3# and #"7874kg/m"^3#.

The density of sodium metal at #"0"^"o""C"# is #"0.968g/cm"^3#, and #"968kg/m"^3#.

In order to determine the density of a substance, you need to know its mass and its volume. Then divide its mass by its volume, remembering to divide the units as well.

Example
A #"1.26cm"^3# sample of the element mercury has a mass of #"17.05g"#. What is it's density?

Solution

#"density"# = #"mass"/"volume"# = #"17.05g"/"1.26cm"^3# =

#"13.5g/cm"^3"#

Here is a video example of how to solve a density problem.