What is the internal energy if system absorbs 100J of heat and does 50J of work on the surrounding?

dE = dH + w

dH = +100 J
w = -50 J

To find the internal energy of a system, you need to use the First Law of Thermodynamics, which states that the change in internal energy (∆U) of a system is equal to the heat (Q) added to the system minus the work (W) done by the system:

∆U = Q - W

In this case, the system absorbs 100J of heat (Q = 100J) and does 50J of work on the surroundings (W = 50J). Now we can calculate the change in internal energy.

∆U = Q - W
∆U = 100J - 50J
∆U = 50J

Therefore, the internal energy of the system in this case is 50J.