Hess' Law

[Ryan Yoon 1L]

Why can we add or subtract enthalpy changes?

[Connie Chen 1E]

Enthalpy is a state property, meaning that it is not dependent on the path taken to obtain that state, and state properties can be added or subtracted.

[Zoe Gleason 4F]

Since it is a state property, only the final and initial state will matter. This allows us to add and subtract the values of enthalpy.

[Ellen Amico 2L]

Yes! Because enthalpy is a state property, we can add or subtract the enthalpy changes in order to get to an overall reaction since the path we take to get there doesn't matter.

[705121606]

yes! this is because it is a state property

[Ashley Alvarado 2C]

Enthalpy changes can be added and subtracted because enthalpy is a state property.

[Leslie Almaraz 4G]

State properties are allowed to be added or subtracted to each other.

[Orrin Zhong 4G]

Enthalpy is a state property, so only the final and initial states matter. The process by which you get from an initial state to a final state does not matter for state properties. Therefore, if you want to find the enthalpy value of a reaction through Hess' Law, you can just add the enthalpy values (ensuring that the intermediates cancel out).