Question

What is happening to the particles as solid→liquid or a liquid→gas and why does it make sense?

Answer 1

As substances change phases, their particle movement and distance from eachother changes

Explanation:

In the gas phase, particles fill up their entire container. (Think about air in a jar) In this phase, the particles are really spread out and zooming around in order to take up large areas of space.

In the liquid phase, particles are closer together and are moving more slowly but they are able to slide past each-other. This is why liquids have definite volume but indefinite shape. (Think about water)

In the solid phase, particles are very close together and are moving very little i.e vibrating, etc. (BUT: they are still moving. Only at absolute zero is there no particle movement)

Hope this helps!