Enthalpy Formula

[Andrew Uesugi 3I]

Can anyone explain to me the formula for enthalpy?

I keep on getting mixed up with a lot of formulas.

[Uma_Rajiyah_2A]

The formula for enthalpy is H=U+PV

U stands for the internal energy of the system
P starts for pressure of the system
V stands for volume of the system

[Vivian Nguyen 2A]

We also use the formula above to show that a change in the enthalpy of a system is equal to the heat release or absorbed at constant pressure.
Since at constant pressure H = U + PV and U = q + w, we see that H = q + w + PV.
If the system can only do expansion work, w = -PexV; thus, H= q - PexV + PV, where Pex = P.
Thus, at constant pressure and with no non expansion work H = q.