______ states that internal energy is a function of state and the increase in internal energy is equal to the sum of the heat supplied to system and work done by the system.

The First Law of Thermodynamics is a statement of the law of conservation of energy. It establishes that internal energy (ΔU) is a state function, and mathematically given by ΔU=q+w (depending on sign conventions where w is the work done on the system).