The heat absorbed in a reaction at constant temperature and constant volume is

Options

A. `DeltaE`
B. `DeltaH`
C. `-DeltaA`
D. `-DeltaG`

Explanation

To solve the question regarding the heat absorbed in a reaction at constant temperature and constant volume, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Terms**:
- Heat absorbed in a reaction is denoted by \( Q \).
- The conditions specified are constant temperature and constant volume.

2. **Applying Thermodynamic Principles**:
- At constant volume, the heat absorbed by the system is equal to the change in internal energy (\( \Delta U \)).
- This relationship can be expressed as:
\[ Q = \Delta U \]
- This means that the heat absorbed at constant volume is directly related to the change in internal energy of the system.

3. **Identifying the Options**:
- The question typically provides multiple-choice answers. In this case, we need to identify which option corresponds to the heat absorbed at constant volume.
- The options might include:
- A) \( \Delta E \) (change in internal energy)
- B) \( \Delta H \) (change in enthalpy)
- C) \( \Delta A \) (change in Helmholtz free energy)
- D) \( \Delta G \) (change in Gibbs free energy)

4. **Evaluating the Options**:
- Since we established that at constant volume, \( Q = \Delta U \), and \( \Delta U \) is often denoted as \( \Delta E \) (change in internal energy), option A is correct.
- The other options (enthalpy, Helmholtz free energy, and Gibbs free energy) are not applicable for heat at constant volume.

5. **Conclusion**:
- Therefore, the heat absorbed in a reaction at constant temperature and constant volume is represented by:
\[ \text{Answer: } \Delta E \]