preface to fifteenth edition

SECTION 6
THERMODYNAMIC PROPERTIES
6.1 ENTHALPIES AND GIBBS ENERGIES OF FORMATION, ENTROPIES, AND
HEAT CAPACITIES 6.1
6.1.1 Some Thermodynamic Relations 6.2
Table 6.1 Enthalpies and Gibbs Energies of Formation, Entropies, and Heat
Capacities of Organic Compounds 6.5
Table 6.2 Heats of Fusion, Vaporization, and Sublimation and Specific Heat at
Various Temperatures of Organic Compounds 6.51
Table 6.3 Enthalpies and Gibbs Energies of Formation, Entropies, and Heat
Capacities of the Elements and Inorganic Compounds 6.81
Table 6.4 Heats of Fusion, Vaporization, and Sublimation and Specific Heat at
Various Temperatures of the Elements and Inorganic Compounds 6.124
6.2 CRITICAL PHENOMENA 6.142
Table 6.5 Critical Properties 6.143
6.1 ENTHALPIES AND GIBBS ENERGIES OF
FORMATION, ENTROPIES, AND HEAT
CAPACITIES
The tables in this section contain values of the enthalpy and Gibbs energy of formation, entropy,
and heat capacity at 298.15 K (25C). No values are given in these tables for metal alloys or other
solid solutions, for fused salts, or for substances of undefined chemical composition.
The physical state of each substance is indicated in the column headed “State” as crystalline solid
(c), liquid (lq), or gaseous (g). Solutions in water are listed as aqueous (aq).
The values of the thermodynamic properties of the pure substances given in these tables are, for
the substances in their standard states, defined as follows: For a pure solid or liquid, the standard
state is the substance in the condensed phase under a pressure of 1 atm (101 325 Pa). For a gas, the
standard state is the hypothetical ideal gas at unit fugacity, in which state the enthalpy is that of the
real gas at the same temperature and at zero pressure.
The values of f H and f G that are given in the tables represent the change in the appropriate
thermodynamic quantity when one mole of the substance in its standard state is formed, isothermally
at the indicated temperature, from the elements, each in its appropriate standard reference state. The
standard reference state at 25Cfor each element has been chosen to be the standard state that is
thermodynamically stable at 25Cand 1 atm pressure. The standard reference states are indicated in
the tables by the fact that the values of f H and f G are exactly zero.
The values of S represent the virtual or “thermal” entropy of the substance in the standard state
at 298.15 K (25C), omitting contributions from nuclear spins. Isotope mixing effects are also excluded
except in the case of the 1 H9 2 H system.
Solutions in water are designated as aqueous, and the concentration of the solution is expressed
in terms of the number of moles of solvent associated with 1 mol of the solute. If no concentration
is indicated, the solution is assumed to be dilute. The standard state for a solute in aqueous solution
is taken as the hypothetical ideal solution of unit molality (indicated as std. state or ss). In this state
6.1