Question

Why is it necessary to use absolute scale in solving gas problem?

Answer 1

It makes sense (classically) that when a gas isn't moving it has no temperature and thus no energy. You could probably reformulate the gas laws so that you could use any temperature scale, but what's the point? It'd just be easier to convert between units. Because the equations only work with an absolute scale.

Answer 2

Explanation:

The Kelvin scale is used in gas law problems because the pressure and volume of a gas depend on the kinetic energy or motion of the particles. The Kelvin scale is proportional to the KE of the particles… that is, 0 K (absolute zero) means 0 kinetic energy. 0 °C is simply the freezing point of water..