Question Detail
Question
The value of ΔU for a system that performs 213 kJ of work on its surroundings and loses 79 kJ of heat is ______ kJ.
Correct Answer
Option C is the correct answer.
Detailed Explanation
ΔU = q + w. The system loses heat: q = -79 kJ. It performs work on surroundings: w = -213 kJ (work done by system is negative). ΔU = -79 + (-213) = -292 kJ.
Hint
First law: ΔU = q + w. Heat lost is negative, work done by system is negative.