Question Detail
Question
The ΔU of a system that releases 12.4 J of heat and does 4.2 J of work on the surroundings is ______ J.
Correct Answer
Option A is the correct answer.
Detailed Explanation
ΔU = q + w. Releases heat: q = -12.4 J. Does work on surroundings: w = -4.2 J (work done by system is negative). ΔU = -12.4 + (-4.2) = -16.6 J.
Hint
Heat released is negative; work done by system is negative.