What states of changing matter put off heat, and what states of changing matter take in heat?

Question

The six changes of states of matter are melting (ice to water), evaporation (water to water vapor), condensation (water vapor to water), sublimation (dry ice to gas), deposition (water vapor to frost), and solidification (water to ice).

Please help!!! I need the answer soon and I can't find it!

Answer 1

Think of it this way:

solid-------->liquid------->gas

least heat-------------->most heat

So if you're going down that chain from a gas to a liquid(condensing) you're going from a state with more heat to a state with less therefore you're releasing heat. If you do the opposite from a liquid to a gas (evaporating) you're going from less heat to more heat so you're taking in heat. It works this way for all of your other phase changes.

Cheers,

Andrew

Answer 2

Changes of state that put out heat are called exothermic.  Those that absorb heat are endothermic.  Melting ice is endothermic, it absorbs heat.  Freezing to ice is exothermic.