Question

Select the state functions among the following.
(A)Temperature
(B)Entropy
(C)Work
(D)Enthalpy

Answer 1

Hint: State function is defined as the system in which its value depends on the initial and final position of the system and not on the path taken to reach that specific point. They depend on the final and initial points of the system. We will keep one thing in mind that if this entity’s value is affected by the path or way taken to establish it then it is a state function and vice versa.

Complete Step by step answer:
- We know that the state function is the one whose value depends on the initial and final points of the process and not on the path taken. We have been given temperature.
- Temperature is the measure of the average kinetic energy of the molecules in the system. Temperature is a state function as processes such as cooling, expansion, the net temperature change depends upon the change in the final states and the initial states and not on the path taken to reach that state.
- Entropy is a measure of the degree of randomness of a system. It is a state function as it is a measure of randomness of a system and it is independent of the path through which it has achieved that state. So it is a state function.
- Work is not a state function as it depends on the path followed to reach that function. It is instead a path function.
- Enthalpy is a state function because it is defined in terms of state functions. It is defined as $H = U + PV$. It is a linear combination of state functions so it is also a state function.
Therefore temperature, enthalpy and entropy are state functions.

Hence the correct answer is options A, B,D.

Note: The closed integral of a state function is zero. Here heat and work are forms of energy in transit. They occur only when there occurs any change in state of the system and surroundings. They don’t exist before or after change of the state.