When the gas in a balloon is heated, the balloon expands. What are the correct signs of heat and work for this change?
A. +Q, -W
B. -Q, +W
C. +Q, +W
D. -Q, -W
The sign for Q is positive because the system is absorbing heat (gas is being heated). And the sign for W is positive because the system is doing work (expanding the gas to expand the balloon).
