The energy available in a system for performing work is called

Options

A. Specific Heat
B. Heat of Formation
C. Gibbs free energy
D. Heat of Vapourisation

Answer

To solve the question "The energy available in a system for performing work is called," we will analyze each of the provided options step by step.

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the term that describes the energy in a system that can be used to perform work. This is a fundamental concept in thermodynamics and biochemistry.

2. **Evaluating Option One - Specific Heat**:
- Specific heat refers to the amount of heat required to raise the temperature of one unit mass of a substance by one degree Celsius.
- This does not relate to the energy available for performing work.

3. **Evaluating Option Two - Heat of Formation**:
- Heat of formation is the heat absorbed or released when a compound is formed from its elements.
- While it involves energy changes, it does not specifically refer to the energy available for work.

4. **Evaluating Option Three - Gibbs Free Energy**:
- Gibbs free energy (G) is defined as the energy of a system that is available to do work at constant temperature and pressure.
- This is the correct term that describes the energy available in a system for performing work.

5. **Evaluating Option Four - Heat of Vaporization**:
- Heat of vaporization is the amount of heat required to convert a unit mass of a liquid into vapor without a change in temperature at constant pressure.
- This also does not pertain to the energy available for work.

6. **Conclusion**: Based on the evaluations, the correct answer is **Option Three - Gibbs Free Energy**.

### Final Answer:
The energy available in a system for performing work is called **Gibbs Free Energy**.

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