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Why are phase changes endothermic?

Posted: Sun Jan 27, 2019 3:03 pm
by Michelle Wang 4I
Why are phase changes from solid-->liquid-->vapor endothermic reactions?

Re: Why are phase changes endothermic?

Posted: Sun Jan 27, 2019 3:14 pm
by 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.

Re: Why are phase changes endothermic?

Posted: Sun Jan 27, 2019 3:37 pm
by varunhariharan
These phase changes all require bonds to be broken which require an input of energy.

Re: Why are phase changes endothermic?

Posted: Sun Jan 27, 2019 3:43 pm
by 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

Re: Why are phase changes endothermic?

Posted: Sun Jan 27, 2019 3:48 pm
by eden tefera 2B
Phase changes like freezing, however release energy into the surroundings so it can be considered exothermic.

Re: Why are phase changes endothermic?

Posted: Sun Jan 27, 2019 4:10 pm
by 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.

Re: Why are phase changes endothermic?

Posted: Sun Jan 27, 2019 4:15 pm
by 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.

Re: Why are phase changes endothermic?

Posted: Sun Jan 27, 2019 4:43 pm
by 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.

Re: Why are phase changes endothermic?

Posted: Sun Jan 27, 2019 4:57 pm
by davidryan3f
Phase changes from solid-->liquid-->vapor are endothermic reactions because it requires an input of heat and energy to break the intermolecular forces.

Re: Why are phase changes endothermic?

Posted: Sun Jan 27, 2019 5:42 pm
by Esther Lee 4H
when you break the forces youre inputting heat so its considered an endothermic reaction

Re: Why are phase changes endothermic?

Posted: Sun Jan 27, 2019 8:33 pm
by 704913468
Phase changes are endothermic because of the heat released from bonds breaking.

Re: Why are phase changes endothermic?

Posted: Sun Jan 27, 2019 8:34 pm
by 704913468
Phase changes are endothermic because of the heat released from bonds breaking.