Question

Why is absolute zero important?

Answer 1

It is the point at which particle motion stops for monatomic ideal gases. However, molecules will still vibrate.

Explanation:

All temperatures above absolute zero will cause particles in any material to move/vibrate slightly, as temperature gives particles Kinetic energy, according to the equipartition theorem for monatomic ideal gases:

`K_(avg)=3/2k_BT`

`k_B` = Boltzmann's constant = `1.38065 times 10^-23 J//K`
`T` = absolute temperature (Kelvin)

At absolute zero, `T = "0 K"`, so there is effectively no average kinetic energy of the molecules. (although the state of absolute zero is more of a concept as it has not yet been achieved). This means that particle motion ceases in monatomic gases.

Absolute zero is also the foundation for the Kelvin scale, as `"0 K" = -273.15^@ "C"` is the coldest that you can ever hope to get.