Thermodynamics Question?

Question

A pot with 50 kg of water is on the stove at an initial temperature of 25C. When the burner is turned on, 800KJ are transferred to the water but 100kJ are transferred from the water to the surroundings. What is the change in internal energy of the water?

Answer 1

energy balance. if 800kj go into the water and 100kj go from the water to the surroundings, you are left with 700kj in the water.