Which of the following is a state function?

Options

A. q + w
B. Entropy
C. Free Energy
D. All of these

Answer

To determine which of the given options is a state function, we first need to understand the definitions of state functions and path functions in thermodynamics.

### Step-by-Step Solution:

1. **Define State Functions and Path Functions**:
- **State Functions**: These are properties that depend only on the state of the system, specifically its initial and final conditions. Examples include internal energy (U), enthalpy (H), entropy (S), and Gibbs free energy (G).
- **Path Functions**: These depend on the specific path taken to reach a particular state. Examples include heat (Q) and work (W).

2. **Identify the Options**:
- Without the specific options provided in the question, we will assume common thermodynamic quantities like internal energy (U), enthalpy (H), entropy (S), Gibbs free energy (G), heat (Q), and work (W).

3. **Analyze Each Option**:
- **Internal Energy (U)**: A state function.
- **Enthalpy (H)**: A state function.
- **Entropy (S)**: A state function.
- **Gibbs Free Energy (G)**: A state function.
- **Heat (Q)**: A path function.
- **Work (W)**: A path function.

4. **Conclusion**:
- From the analysis, we can conclude that internal energy, enthalpy, entropy, and Gibbs free energy are state functions. Heat and work are not state functions as they depend on the path taken.

5. **Final Answer**:
- If the options include internal energy, enthalpy, entropy, and Gibbs free energy, then all of these are state functions. If the question asks for a specific answer, choose any of these as they are all correct.