Why are phase changes endothermic?

[Michelle Wang 4I]

Why are phase changes from solid-->liquid-->vapor endothermic reactions?

[705170809]

Phase changes are endothermic because heat is required to break the bonds between the atoms in order for it to go from a solid to a liquid or a liquid to a gas. This is why during a phase change, the temperature does not change.

[varunhariharan]

These phase changes all require bonds to be broken which require an input of energy.

[Jonathan Pai 2I]

Think of how we looked at endothermic reactions in equilibrium and boiling water. If you boil water (add heat), what happens. Water vapor is formed (product), so the added heat from the stove created more products, which is the characteristic of an endothermic reaction.

H2O(l) + heat <> H2O(g) , shifts right when heat added

[eden tefera 2B]

Phase changes like freezing, however release energy into the surroundings so it can be considered exothermic.

[Lisa Werner 2F]

Phase changes involving the breaking of bonds (solid->liquid->gas) are endothermic because they require/absorb heat. Phase changes involving the formation of bonds (gas->liquid->solid) are exothermic because the release heat.

[chris_tsai_4H]

Phase changes are endothermic because, in order to go from one state of matter to another, the bonds have to be broken, which requires heat.

[Mhun-Jeong Isaac Lee 1B]

Phase change from solid to liquid to gas requires energy in order for the bonds to be broken. Therefore, they are endothermic.

[davidryan3f]

Phase changes from solid-->liquid-->vapor are endothermic reactions because it requires an input of heat and energy to break the intermolecular forces.

[Esther Lee 4H]

when you break the forces youre inputting heat so its considered an endothermic reaction

[704913468]

Phase changes are endothermic because of the heat released from bonds breaking.

[704913468]

Phase changes are endothermic because of the heat released from bonds breaking.