PRACTICE / First law of thermodynamics

Which way does energy cross the boundary?

A sealed gas in a piston absorbs 480 J as heat. During the same process it expands and does 170 J of work on its surroundings.

What is the change in the gas’s internal energy?

1. A$+650\ \mathrm{J}$
2. B$+310\ \mathrm{J}$
3. C$-310\ \mathrm{J}$
4. D$+480\ \mathrm{J}$

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