chemistry lesson

Question

A system does 536 kJ of work and loses 246 kJ of heat to the surroundings.

What is the change in internal energy, Δ𝐸, of the system? Note that internal energy is symbolized as Δ𝑈 in some sources.

Answer 1

∆E = q + w

q = heat = -246 kJ (negative because heat is lost)

w = work = -536 kJ (negative because the system is doing the work on the surrounding)

∆E = ∆U = -246 kJ + -536 kJ

∆E = ∆U = -782 kJ