ΔH

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Dina 2k
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Joined: Wed Sep 18, 2019 12:17 am

ΔH

Postby Dina 2k » Wed Feb 05, 2020 6:02 pm

I remember discussing how to find ΔH(Fusion/Vaporization) but I can't find it in my notes. Can someone please eloborate a bit on the equation used? and if we are told to calculate heat of fusion (q), will we be given ΔHf?

Jordan Young 2J
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Joined: Thu Jul 25, 2019 12:17 am
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Re: ΔH

Postby Jordan Young 2J » Wed Feb 05, 2020 6:19 pm

ΔH of fusion is the change in enthalpy required for a substance to undergo a phase change from liquid to solid (or solid to liquid) and ΔH of vaporization is the change in enthalpy required for a substance to undergo a phase change from liquid to gas (or gas to liquid). You would use these values to calculate the q value for phase change by multiplying the number of moles by the corresponding ΔH. And usually yes we would be given the value.

Sanjana Munagala_1j
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Re: ΔH

Postby Sanjana Munagala_1j » Fri Feb 07, 2020 10:48 am

When we are calculating ΔH vaporization we could calculate it by subtracting ΔHf of the liquid from ΔHf of the gas. (ΔHf gas- ΔHf liquid) or (final - initial). However, usually these values are given to you as per mole values and so when calculating them in problems just multiply the given values by the number of moles of substance.

Hope that helps!

Anna Heckler 2C
Posts: 102
Joined: Wed Sep 18, 2019 12:18 am

Re: ΔH

Postby Anna Heckler 2C » Fri Feb 07, 2020 12:43 pm

ΔHfusion and vaporization are given values, so you do not need to worry about memorizing them!

Ying Yan 1F
Posts: 101
Joined: Fri Aug 02, 2019 12:16 am

Re: ΔH

Postby Ying Yan 1F » Sun Feb 09, 2020 4:25 pm

From what a recall, Delta H of formation and condensation will usually be given to you in a problem, and you will need to find the net delta H through the given values.


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