DENSITY
The property of density is intrinsic to a substance; substances such as water,
lead, carbon dioxide, or ethyl alcohol, for example, all have different densities.
Density is a measure of the ratio of an object’s mass to its volume.
Generally, if we say “water is heavy,” we mean that water has a high density
relative to other substances. Ten kilograms of water occupy a relatively small
volume—about 10 L. When we say “feathers are light,” we mean that feathers
have a low density relative to other substances. Ten kilograms of feathers occupy
a relatively large volume.
How do we measure density? We measure it in units that reflect mass per
volume. That means we might measure it in g/L, or mg/L, or kg/mL, or any
other combination that represents mass per volume. We calculate density using
the following formula:
density = Consider a 2 mL sample of substance X and a 2 mL sample of substance Y. The
sample of substance X weighs 8 grams, and the sample of substance Y weighs 6
grams. Therefore:
Density X = = 4 g/mL