Question

600 J of work is done on a system in a process that decreases the thermal energy of the system by 300 J.
How much heat energy is transferred to or from the system as heat?
Write positive value if the energy is transferred to the system and negative if the energy is transferred from the system.

Answer 1

Answer:

900 J

Explanation:

$\Delta U$ = Change in entropy = -300 J (Decrease)

$W$ = Work done = 600 J

$Q$ = Heat transferred

Change in internal energy is given by

$\Delta U=W+Q\\\Rightarrow Q=\Delta U-W\\\Rightarrow Q=-300-600\\\Rightarrow Q=-900\ J$

The heat transferred to or from the system as heat is -900 J.

900 J is transferred. As heat is transferred from the system the sign is negative.