difference of internal energy equation

[Jeilyn Rhee 1J]

In physics, the change in internal energy is written as q-w but in chemistry we write it as q+w. Why is there a difference?

[Vincent Tran 3B]

It might be easier to always think of w as work in which case when w is positive work is being done to a system and a negative work would mean the system is doing work in the surroundings. In chemistry the formula would be q + w because we are looking for work done to the system whilst in physics it matters more as to what the system is doing to its surroundings.