To determine how many of the listed items are state functions, we first need to clarify what a state function is. A state function is a property of a system that depends only on its current state, not on the path taken to reach that state. This means that the value of a state function is determined solely by the conditions of the system, such as temperature, pressure, and composition, rather than how the system arrived at those conditions.
Identifying State Functions
Let’s analyze each item in your list:
- Internal Energy (I): This is a state function. It represents the total energy contained within a system, depending only on the state of the system (temperature, pressure, etc.).
- Molar Enthalpy (II): This is also a state function. Molar enthalpy is defined as the heat content per mole of a substance at a given temperature and pressure, and it is independent of how the system reached that state.
- Irreversible Expansion Work (III): This is not a state function. The work done during an irreversible process depends on the specific path taken, such as the external pressure and the manner of expansion.
- Heat Supplied (IV): This is not a state function. The amount of heat transferred can vary depending on the process (e.g., isothermal, adiabatic) and is path-dependent.
- Gibbs Free Energy (V): This is a state function. Gibbs free energy is a measure of the maximum reversible work that can be performed by a thermodynamic system at constant temperature and pressure, and it only depends on the state of the system.
- Entropy (VI): This is a state function. Entropy measures the degree of disorder or randomness in a system and is determined solely by the state of the system.
- Reversible Expansion Work (VII): This is also not a state function. While it is defined for a specific process, the work done can vary based on the path taken, even if the initial and final states are the same.
Summary of Findings
From the analysis above, we can conclude that the following are state functions:
- Internal Energy (I)
- Molar Enthalpy (II)
- Gibbs Free Energy (V)
- Entropy (VI)
Thus, there are four state functions in your list. Understanding the distinction between state functions and path-dependent properties is crucial in thermodynamics, as it helps in analyzing energy changes and system behavior under various conditions.
