This quantity is conserved in an ideal Hampson–Linde cycle, which is used in the liquefaction of gases. At a constant value of this quantity, hydrogen, helium, and neon warm upon expansion because they have very small inversion temperatures. The differential for this quantity is equal to “T dS + V dp” when particle number is held constant. Throttling processes conserve (10[1])this quantity via the Joule–Thomson effect. In the thermodynamic square, this quantity is the only non-energy potential. Along with energy, the Born–Haber cycle calculates a “lattice” version of this quantity (10[1])from Hess’s law. This quantity, equal to the sum of the internal energy plus pressure times volume, is negative for exothermic processes. For 10 points, name this state function denoted H. ■END■