Internal Energy State Property

[Eric Sun 2G]

Hi so Dr. Lavelle said in the lecture that internal energy U is a state property and that delta U = q +w. However, q and w are non-state properties and so I was wondering if someone can clarify why we can add non-state properties together to get U, which is a state property?

[sadiebrebes]

Hi so Dr. Lavelle said in the lecture that internal energy U is a state property and that delta U = q +w. However, q and w are non-state properties and so I was wondering if someone can clarify why we can add non-state properties together to get U, which is a state property?

Hi, there is no rule saying that adding path functions wont get you state functions. the change in Internal energy is a state functions because it will measure the same no matter the path taken to get to that energy. Work is a path function as is q, because they rely on the transition from the initial to final state. When they are added, this is all of the internal energy change.