How Do Catalysts Affect Enthalpy in Reactions?

[brake4country]

Homework Statement

This question is just for an overall understanding of enthalpy and activation. My book states that catalysts decrease the activation energy of a reaction. This makes sense. However, how does this change the enthalpy? If a catalyst creates a new pathway, wouldn't the enthalpy change be different as compared to the reaction without a catalyst? Thanks in advance.

Homework Equations

NA

The Attempt at a Solution

 

[Bystander]

However, how does this change the enthalpy?

It doesn't change the enthalpy of the reaction. It does change the activation enthalpy of the reaction.

Enthalpy of a reaction is the difference in enthalpies only between the initial and final states. Activation energy or activation enthalpy is the maximum energy change on the path the reaction takes between those initial and final states.

 

[brake4country]

Oh I get it but let me be clear. Initial and final states (as defined by state functions) will be the same regardless if the reaction uses a catalyst. Thus E_a is lower but the ΔH for both will be the same?

 

[Bystander]

You are cooking.

 

[brake4country]

Thank you!