work, heat, and internal energy

[Simrina Desar Dis 1H]

The change in internal energy is the sum of work and heat. Both work and heat are not state functions, however internal energy is a state function. Why does adding together 2 not state functions produce a state function?

[Gevork 2E]

Internal energy is a state function because it does not matter how the system gets to that particular state. Work on the other hand, is proportional to distance traveled, so it matters how you got to your endpoint/ what path you took. Heat is similar.

Hope this was helpful.

[Lisa Tang 1C]

To add on to this, internal energy is the sum of heat and work, as you stated. However, each of these components does not have to be present to calculate internal energy. For example, if no work is being done by the system, then the internal energy is just set equal to heat (U=q). So, no matter what path you take to get to the final internal energy, you will end up at the same answer as if you calculated internal energy with work being done by the system, but less heat absorbed.