if the reaction is reversible all is at equilibrium (`DeltaS_universe = 0`), then the entropy of the system

Options

A. will change abruptly
B. is greater than 1
C. will remain constant
D. is equal to 0

Answer

To solve the question regarding the entropy of a system at equilibrium during a reversible reaction, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Concept of Equilibrium**:
- In a reversible reaction at equilibrium, the rates of the forward and reverse reactions are equal. This means that the concentrations of reactants and products remain constant over time.

**Hint**: Remember that equilibrium indicates no net change in the concentrations of reactants and products.

2. **Entropy and the Universe**:
- The change in entropy of the universe (\( \Delta S_{universe} \)) is defined as the sum of the change in entropy of the system (\( \Delta S_{system} \)) and the change in entropy of the surroundings (\( \Delta S_{surroundings} \)).
- At equilibrium for a reversible process, \( \Delta S_{universe} = 0 \).

**Hint**: Recall the relationship: \( \Delta S_{universe} = \Delta S_{system} + \Delta S_{surroundings} \).

3. **Implications of \( \Delta S_{universe} = 0 \)**:
- If \( \Delta S_{universe} = 0 \), it implies that the change in entropy of the system and the surroundings must balance each other out. For a reversible process at equilibrium, this means that there is no net change in the entropy of the system.

**Hint**: Think about how the entropy of the system and surroundings must interact to keep the total entropy change at zero.

4. **Conclusion about the Entropy of the System**:
- Since the system is at equilibrium and there is no net change in the concentrations of reactants and products, the entropy of the system remains constant. Thus, we can conclude that the entropy of the system does not change.

**Hint**: Remember that at equilibrium, the state of the system is stable, leading to no change in entropy.

### Final Answer:
The entropy of the system will remain constant.