Indentify the true statement(s)

Options

A. A catalyst is chemically unchanged at the end of a reaction
B. A catalyst may appear in the kinetic rate equation of the reaction
C. A catalyst will not affect the composition of an equilibrium mixture
D. A catalyst cannot cause a non-spontaneous `(DeltaG gt 0)` reaction to proceed

Answer

To identify the true statements regarding catalysts, we will analyze each statement based on the information provided in the transcript.

### Step-by-Step Solution:

1. **Statement 1: A catalyst is chemically unchanged at the end of a reaction.**
- A catalyst participates in the reaction and may be consumed during the reaction, but it is regenerated at the end. Therefore, it is chemically unchanged at the end of the reaction.
- **Conclusion**: This statement is true.

2. **Statement 2: A catalyst may appear in the kinetic rate equation of the reaction.**
- A catalyst can take part in the rate-determining step, which is the slowest step of the reaction. Since it can influence the rate of reaction, it may appear in the kinetic rate equation.
- **Conclusion**: This statement is true.

3. **Statement 3: A catalyst will not affect the composition of an equilibrium mixture.**
- A catalyst increases the rate at which equilibrium is reached but does not change the composition of the equilibrium mixture itself. It only speeds up the process of reaching equilibrium.
- **Conclusion**: This statement is true.

4. **Statement 4: A catalyst cannot cause a spontaneous, non-spontaneous reaction to proceed.**
- A catalyst can only affect the rate of both forward and reverse reactions. It cannot make a non-spontaneous reaction spontaneous; it only facilitates the reaction process.
- **Conclusion**: This statement is true.

### Final Conclusion:
All the statements regarding catalysts are true.