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Phase Changes

Posted: Sun Jan 26, 2020 8:01 pm
by Vuong_2F
For reactions where substances are not in their most stable/standard phase, how would you account for that when calculating enthalpies?

Re: Phase Changes

Posted: Sun Jan 26, 2020 8:05 pm
by Christine Honda 2I
If the substance is not in the most stable/standard phases then you must use the total of the enthalpy of the phase change and the bond enthalpy when calculating.

Re: Phase Changes

Posted: Sun Jan 26, 2020 8:32 pm
by Chris Charton 1B
When the substance is not in its standard state at the given temperature, you have to add the enthalpy of its phase changes. For example if its a gas in its standard state and is currently a solid, you would have to add the enthalpy of its sublimation.

Re: Phase Changes

Posted: Sun Jan 26, 2020 8:47 pm
by 405268063
Yes, as the previous response said, you must add the enthalpy of the phase change.

Re: Phase Changes

Posted: Sun Jan 26, 2020 8:56 pm
by rohun2H
Add the enthalpy of the phase change.

Re: Phase Changes

Posted: Sun Jan 26, 2020 8:58 pm
by gabbymaraziti
You should calculate the enthalpy, then add the enthalpy of the phase change.

Re: Phase Changes

Posted: Sun Jan 26, 2020 9:13 pm
by Eesha Chattopadhyay 2K
The proper method is to calculate the enthalpy, then add the enthalpy of the phase change.

Re: Phase Changes

Posted: Sun Jan 26, 2020 10:28 pm
by Joowon Seo 3A
To accommodate for the phase change of the material, add the reaction enthalpy of the phase change onto the reaction.