But America has a higher suicide raterate?

So in a solid, you can imagine each atom connected to each other by springs (bonds). They can vibrate on these springs. If they vibrate too much (by heating) then they can break the bonds and escape as a gas. Gasses basically have too much energy to bond again.

Molecules interact with each other. Energy is transferred as they bump around. If you were to follow a single molecule it would move around randomly. What we can measure is usually the average of many molecules.