THE PRACTICE STUDIO
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PRACTICE / First law of thermodynamics
Two transfers with opposite sign conventions
A gas loses 70 J as heat while a piston does 120 J of work on it.
What is the change of the gas’s internal energy?
Organize the givens & assumptions
- Heat leaves: 70 J
- Work on gas: 120 J
Closed fixed amount of ideal gas, constant stated heat capacities, negligible bulk kinetic and gravitational energy changes, and only pressure–volume work. Heat into the gas and work by the gas are positive.
- A
- B
- C
- D
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