Homework Problem 10 Is Internal Energy a point or a path fun

Homework Problem 10: Is Internal Energy a point or a path function? Is work done a point or a path function? Homework Problem 1: What assumptions are we making when we state E = U. Homework Problem 12: Give expressions for variation of Cp with temperature (T) for Air, CO2, O2 and He. Assume Air, CO2, O2 and He to be ideal gases.

Solution

10) The internal energy is a point function of a system, because its value depends only on the current state of the system and not on the path taken or processes undergone to prepare it. It is an extensive quantity.

Work done is a path function. It is something that we measure while a system changes its position from one state to another state and can have any value depending on the path that is taken by the system to reach the final state.

11) Heat and work are mutually convertible but since energy can neither be created nor destroyed, the total energy associated with the energy conversion remains constant.

No machine can produce energy without corresponding expenditure of energy, i.e., it is impossible to construct a perpetual motion machine of first kind.

Q=E+W

Q=U+W ...( if electric, magnetic, chemical energies are absent and changes in potential and kinetic energies and neglected)