A 1 kg steel *** contains 1 kg liquid water both at 15°C. It is now put on the stove where it is heated to the boiling point of the water. Neglect any air being heated and find the total amount of energy needed.
Energy Eq U2 − U1= 1Q2 − 1W2
The steel does not change volume and the change for the liquid is minimal, so 1W2 ≅ 0.