Liquids and Solids

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Abby Ellstrom 1I
Posts: 53
Joined: Fri Sep 29, 2017 7:04 am

Liquids and Solids

Postby Abby Ellstrom 1I » Thu Jan 11, 2018 6:30 pm

If enthalpy change is in terms of gaseous substances, how do you determine the enthalpy change in the dissociation of a liquid or solid?

Diego Zavala 2I
Posts: 65
Joined: Fri Sep 29, 2017 7:07 am
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Re: Liquids and Solids

Postby Diego Zavala 2I » Thu Jan 11, 2018 8:58 pm

The back of the textbook should have a table of enthalpy values for the different physical states of common compounds, however, I dont think that there exist an equation that allows you to calculate the enthalpy of ice given the enthalpy of water

Julia Cheng 2J
Posts: 31
Joined: Thu Jul 13, 2017 3:00 am

Re: Liquids and Solids

Postby Julia Cheng 2J » Fri Jan 12, 2018 11:30 am

Yes, even for the same substance, its standard enthalpy of formation is different depending on what state it is in. On tests and in the textbook, the standard enthalpies of formation are given and specific to whatever physical state the molecule is in, so we have to pay attention to that.

Lucia H 2L
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Re: Liquids and Solids

Postby Lucia H 2L » Fri Jan 12, 2018 8:06 pm

The back of the book does have standard enthalpy of formation for several compounds in multiple states. It is definitely listed for water in solid, liquid and gas forms (they just did the phase conversion for us).

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