Delta U
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Delta U
When calculating the internal energy of the system how do you know when to change the sign of q/w?
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Re: Delta U
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
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Re: Delta U
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.
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Re: Delta U
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.
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