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Delta U
Posted: Sun Mar 15, 2020 11:42 pm
by Abigail Menchaca_1H
When calculating the internal energy of the system how do you know when to change the sign of q/w?
Re: Delta U
Posted: Sun Mar 15, 2020 11:45 pm
by DarrenKim_1H
Multiple factors indicate whether to change the sign. For example if work is done on the system it is positive and if it is done by then it is negative
Re: Delta U
Posted: Mon Mar 16, 2020 12:08 am
by Diana A 2L
Also, if heat is released, q is negative, and if it's absorbed, q is positive. Then you use the delta U= q+w equation to determine if overall internal energy is positive or negative.
Re: Delta U
Posted: Mon Mar 16, 2020 6:08 pm
by Ayushi2011
Depends on whether work is done or work is being done on the system.
Re: Delta U
Posted: Mon Mar 16, 2020 8:16 pm
by Owen-Koetters-4I
you examine if work is done on or by the system
Re: Delta U
Posted: Mon Feb 01, 2021 1:30 pm
by Frankie Mele 3J
The change in sign of delta U is a combination of both heat and work done by a system.
Re: Delta U
Posted: Mon Feb 01, 2021 7:11 pm
by My-Lan Le 1L
Like all of the other comments are saying, this factor depends on whether work is being done onto a system or the system is doing work on its environment. For example, in a closed system with a piston, if the piston moves downwards and the system is being compresses, ∆U would be positive. Alternatively, if the piston moves upwards and the system is expanding, ∆U would be negative.