In a process, 701 J of heat is absorbed by a system and 394 J of work is done by the system. What is the change in internal energy for the process?

We know that,

ΔU = ΔH + W

Where ΔU is change in internal energy

Δ H is change in enthalpy

And W is work done on the system.

Given, 701 J of heat is taken by the system

Thus ΔH = 701 J

And 394 J of work is done by the system

Thus W = - 394

∴ ΔU = 701 – 394

= 307 J