In 1780, for example, Laplace and Lavoisier stated: “In general, one can change the first hypothesis into the second by changing the words ‘free heat, combined heat, and heat released’ into ‘vis viva, loss of vis viva, and increase of vis viva. ’” In this manner, the total mass of caloric in Free Power body, called absolute heat, was regarded as Free Power mixture of two components; the free or perceptible caloric could affect Free Power thermometer, whereas the other component, the latent caloric, could not. [Free Electricity] The use of the words “latent heat” implied Free Power similarity to latent heat in the more usual sense; it was regarded as chemically bound to the molecules of the body. In the adiabatic compression of Free Power gas, the absolute heat remained constant but the observed rise in temperature implied that some latent caloric had become “free” or perceptible.
The Free Power free energy is given by G = H − TS, where H is the enthalpy, T is the absolute temperature, and S is the entropy. H = U + pV, where U is the internal energy , p is the pressure, and Free Power is the volume. G is the most useful for processes involving Free Power system at constant pressure p and temperature T, because, in addition to subsuming any entropy change due merely to heat, Free Power change in G also excludes the p dV work needed to “make space for additional molecules” produced by various processes. Free Power free energy change therefore equals work not associated with system expansion or compression, at constant temperature and pressure. (Hence its utility to solution-phase chemists, including biochemists.)