Heat and work

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Tam To 1B
Posts: 72
Joined: Fri Sep 28, 2018 12:25 am

Heat and work

Postby Tam To 1B » Tue Jan 29, 2019 11:24 am

What is the difference between heat and work? How do they relate to internal energy?

Dimitri Speron 1C
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Joined: Fri Sep 28, 2018 12:17 am
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Re: Heat and work

Postby Dimitri Speron 1C » Tue Jan 29, 2019 11:37 am

Heat and work both contribute to change in internal energy by the equation (delta)U = heat + work. When you have heat exiting the system you subtract from internal energy. Heat into a system adds to internal energy. Work done on a system adds to internal energy, work done by a system subtracts internal energy.

Amy Dinh 1A
Posts: 62
Joined: Fri Sep 28, 2018 12:23 am

Re: Heat and work

Postby Amy Dinh 1A » Tue Jan 29, 2019 3:47 pm

Heat is the transfer of energy between thermodynamical systems, while work is the transfer of energy other than work.

They are related in the equation: delta U = q +w
where U is the change in internal energy, q is the heat transferred in or out of the system, and w is work.

Kate_Santoso_4F
Posts: 72
Joined: Fri Sep 28, 2018 12:29 am

Re: Heat and work

Postby Kate_Santoso_4F » Tue Jan 29, 2019 4:02 pm

Heat, represented by q, is the transfer of energy as a result of a temperature difference. When energy enters a system as heat, q is positive. When energy leaves a system as heat, q is negative. The measurement of heat produced or absorbed by a process is used to monitor the delta U, or internal energy, of a system. Work, represented by w, is the process of achieving motion against an opposing force so it is the transfer of energy to a system. If work is done on a system, w is positive. If work is done by the system, w is negative. The internal energy is the total store of energy in a system. Heat, work, and internal enrgy are related by the following equation: delta U = heat (q) + work (w)

Sean Reyes 1J
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Joined: Fri Sep 28, 2018 12:24 am

Re: Heat and work

Postby Sean Reyes 1J » Tue Jan 29, 2019 4:17 pm

Work is the transfer of energy to a system through non-thermodynamic situations (basically just not through temperature differences). Work done on a system results in a positive value of w, while work done BY the system results in a negative value of w.
Heat, in terms of thermodynamics, refers to the transfer of energy as well. This is caused by a difference of temperature. When heat enters a system, this results in a positive value of q, whereas a negative value of q comes from heat exiting the system.
Heat, work, and energy are related through:
delta U = q + w,
where delta U is the change of the internal energy of the system (q and w are already explained earlier!)
I hope this helps!


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