ΔH

[lizettelopez1F]

Is ΔH always equal to qp? Also, under what circumstances does ΔH=ΔU?

[ian_haliburton_1f]

Delta H equals qp for a system under constant pressure where the only work involved is the work of expansion. Since delta H is included for conditions in which there is usually work involved, it is more usual that delta U will equal delta H plus work.

[Parth Mungra]

For most liquid and aqueous solutions (not gases) dU=dV=qp because there is no change in volume, and thus no change in expansion work. w=0 is when they are equal.