Question

How does the density of a liquid (or gas) vary
with temperature ?
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Answer 1

Density is the ratio of mass to volume. When the temperature varies, the volume of the liquid changes.

Cooling a substance causes molecules to slow down and get slightly closer together, occupying a smaller volume that results in an increase in density.

When the temperature of the gas molecules increases, it increase the energy of the molecules. As such, the Kinetic energy of the Molecules increase, which means the volume increases. This mean the intermolecular space increases.

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