deltaH and q

Hi everyone,

I'm having trouble wrapping my head around the deltaH = deltaU + PdeltaV equation
My main issue is this: doesn't deltaU already include PV work in its equation deltaU = q + w = heat + PV work? So why is it considered twice in the enthalpy equation, and why is deltaH = q when there is no change in volume valid?

This concept has been driving me crazy. Thanks!