Is a rubbing alcohol evaporating absorbing or releasing energy?

Answer 1

Actually both, in the liquid state molecules are moving around and colliding all the time (with themselves and the gases around it), usually when collisions occur one molecule transfers energy to the other, if a molecule is close to the surface and gains enough energy to escape the liquid it evaporates, in that case you can say that the liquid released energy in the vapour, but the molecule that evaporated did so because it gained energy and was close to the surface. Evaporation is just the act of the molecule escaping the rest of the liquid, it does not transfer any energy itself, it just happened because of the energy transfer between the molecules in the liquid. When the water molecules react with the gases around it (when they break down into gases or other compounds - remember vapour is not a gas, it's a mix of gas and liquid) then energy may be absorbed or released but that depends on the specific reaction.

When heat is applied the liquid absorbs the heat energy and that means the molecules move faster and collide harder and more often, so evaporation rate increases. In that case you can say that the liquid absorved energy from the heat source and released in the vapour, but evaporation occurs regardless of wheather the liquid itself it's absorving energy, just at a lower rate.

When you rub alcohol on your skin it feels cool because the liquid alcohol is absorbing energy from your skin and releasing it in the vapour, it feels cooler than water because alcohol evaporates faster.

The short answer would be, the molecules that evaporate absorb energy while the rest of the liquid releases it.

Boiling is something else, evaporation happens on the surface of the liquid while boiling happens troughout the whole liquid, in the case of boiling it would be absorving energy.