- #1

- 2

- 0

ΔH = ΔU + Δ(PV) = ΔU + RΔT

So far so good. I also understand the relationship:

ΔU = Q + W... (W here is work being done on the system)

In an adiabatic reversible process, Q = 0, which also makes sense. So,

W = ΔU = nC

_{v}ΔT

Now, where my confusion lies is in the next part. My book works out a problem, and says:

ΔH = W = nC

_{p}ΔT

How can both ΔU and ΔH equal W? This doesn't make sense to me, unless Δ(PV) from the first equation was 0. I don't see how this could be 0 unless we were talking about an isothermal case. It also doesn't make sense because W can't equal both nC

_{v}ΔT and nC

_{p}ΔT simultaneously, since C

_{p}= C

_{v}+ R.

Am I missing something?