Work vs. Enthalpy


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Helen Struble 2F
Posts: 97
Joined: Sat Aug 24, 2019 12:17 am

Work vs. Enthalpy

Postby Helen Struble 2F » Sun Feb 02, 2020 8:46 pm

Is there any scenario in which a closed reaction would do work on the system but still have a positive enthalpy? So, if delta U = q + w, is it possible for a system to lose heat but still expand, doing work on the system? Or is every reaction that causes work of expansion also exothermic?

Jessica Booth 2F
Posts: 101
Joined: Fri Aug 30, 2019 12:18 am

Re: Work vs. Enthalpy

Postby Jessica Booth 2F » Sun Feb 02, 2020 9:57 pm

Yes, there are scenarios where a closed reaction would do work on the system but still have positive enthalpy because the sign of the enthalpy doesn't indicate anything about the work. It is possible for a system to lose heat, having a negative q but do work on the surroundings by expanding. Exothermic refers to whether delta H is positive or negative, and delta H is the amount of heat released or absorbed by a reaction. In other words, you can have a reaction that causes work be exothermic or endothermic.


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