Question

why density of a substance decreases with increase in temperature​

Answer 1

Answer:

Densities of substances don't decrease with temperature. On the contrary, it increases with decrease in temperature. ... Since density is inversely proportional to volume, as density decreases with an increase in volume. Hence, density decreases with an increase in temperature.

Answer 2

Answer:

Density changes with temperature because volume changes with temperature. Density is mass divided by volume. As you heat something up, the volume usually increases because the faster moving molecules are further apart. Since volume is in the denominator, increasing the volume decreases the density.