Calculating the density of matter

The density of a substance is a scalar physical quantity defined as the ratio of the mass of a body to the volume occupied by this body. Based on the definition of density, it is customary to measure it in kg / m³.


Body density calculation

Weight, kg:
Volume, m3:

The density is found by the formula:

where m — is body weight, V — its volume;

When calculating the density of gases under standard conditions, this formula can also be written in the form:

Where М —
molyarnaya massa
molar mass газа,  V— molar volume (under standard conditions, it is approximately equal to 22.4 l / mol).

As a rule, as the temperature decreases, the density increases, although there are substances whose density in a certain temperature range behaves differently, for example, water, bronze and cast iron. Thus, the density of water has a maximum value at 4 ° C and decreases with both increasing and decreasing temperature relative to this value.

With a change in the state of aggregation, the density of a substance changes abruptly: the density increases during the transition from a gaseous state to a liquid and when the liquid solidifies. Water, silicon, bismuth and some other substances are exceptions to this rule, since their density decreases during solidification.