Question

What will be the change in internal energy of a system that absorbs 300 J of heat and performs 500 J of work?

Calculate the change in internal energy, 400 J of work is done on the system and the system losses 225 J of heat energy.

Answer 1

1) $\Delta E=Q+W=300\ J -500\ J=-200\ J$

2) $\Delta E=Q+W=-225\ J+400\ J=175\ J$