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J/(mol K) Liquid properties Std enthalpy change of formation, Δ f H o liquid: −80.882 ± 0.053 kJ/mol [2] Standard molar entropy, S o liquid? J/(mol K) Heat capacity, c p: 80.80 J/(mol K) Gas properties Std enthalpy change of formation, Δ f H o gas: −45.556 ± 0.029 kJ/mol [3] Std Gibbs free energy change of formation, Δ f G o gas: −16 ...
At 15.6 °C (60.1 °F), the density of a saturated solution is 0.88 g/ml; it contains 35.6% ammonia by mass, 308 grams of ammonia per litre of solution, and has a molarity of approximately 18 mol/L. At higher temperatures, the molarity of the saturated solution decreases and the density increases. [ 8 ]
The standard enthalpy change of combustion, ΔH° c, expressed per mole of ammonia and with condensation of the water formed, is −382.81 kJ/mol. Dinitrogen is the thermodynamic product of combustion: all nitrogen oxides are unstable with respect to N 2 and O 2, which is the principle behind the catalytic converter.
The molar mass of atoms of an element is given by the relative atomic mass of the element multiplied by the molar mass constant, M u ≈ 1.000 000 × 10 −3 kg/mol ≈ 1 g/mol. For normal samples from Earth with typical isotope composition, the atomic weight can be approximated by the standard atomic weight [ 2 ] or the conventional atomic weight.
Note that the especially high molar values, as for paraffin, gasoline, water and ammonia, result from calculating specific heats in terms of moles of molecules. If specific heat is expressed per mole of atoms for these substances, none of the constant-volume values exceed, to any large extent, the theoretical Dulong–Petit limit of 25 J⋅mol ...
The molar mass is defined as the mass of a given substance divided by the amount of the substance, and is expressed in grams per mol (g/mol). That makes the molar mass an average of many particles or molecules (potentially containing different isotopes), and the molecular mass the mass of one specific particle or molecule. The molar mass is ...
The term molality is formed in analogy to molarity which is the molar concentration of a solution. The earliest known use of the intensive property molality and of its adjectival unit, the now-deprecated molal, appears to have been published by G. N. Lewis and M. Randall in the 1923 publication of Thermodynamics and the Free Energies of Chemical Substances. [3]
Atomic number Element Molar mass Formal standard atomic weight s.a.w., formal short Note Z calculated; g·mol −1 A r, standard [2] A r, abridged and conventional [2]; C 9 H 8 O 4: 180.159 g·mol −1