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A Assuming an altitude of 194 metres above mean sea level (the worldwide median altitude of human habitation), an indoor temperature of 23 °C, a dewpoint of 9 °C (40.85% relative humidity), and 760 mmHg sea level–corrected barometric pressure (molar water vapor content = 1.16%). B Calculated values *Derived data by calculation.
The enthalpy of solution is most often expressed in kJ/mol at constant temperature. The energy change can be regarded as being made up of three parts: the endothermic breaking of bonds within the solute and within the solvent, and the formation of attractions between the solute and the solvent.
A closely related property of a substance is the heat capacity per mole of atoms, or atom-molar heat capacity, in which the heat capacity of the sample is divided by the number of moles of atoms instead of moles of molecules. So, for example, the atom-molar heat capacity of water is 1/3 of its molar heat capacity, namely 25.3 J⋅K −1 ⋅mol ...
The molar differential heat of dilution is thus defined as the enthalpy change caused by adding a mole of solvent at a constant temperature and pressure to a very large amount of solution. Because of the small amount of addition, the concentration of dilute solution remains practically unchanged.
≘ 2 625.499 639 4799 (50) kJ/mol ≘ 627.509 474 0631 (12) kcal/mol ≘ 219 474.631 363 20 (43) cm −1 ≘ 6 579.683 920 502 (13) THz. where: ħ is the reduced Planck constant, m e is the electron mass, e is the elementary charge, a 0 is the Bohr radius, ε 0 is the electric constant, c is the speed of light in vacuum, and; α is the fine ...
The standard enthalpy of formation is measured in units of energy per amount of substance, usually stated in kilojoule per mole (kJ mol −1), but also in kilocalorie per mole, joule per mole or kilocalorie per gram (any combination of these units conforming to the energy per mass or amount guideline).
6.01 kJ/mol Entropy change of fusion at 273.15 K, 1 bar, Δ fus S: 22.0 J/(mol·K) Std enthalpy change of vaporization, Δ vap H o: 44.0 kJ/mol Enthalpy change of vaporization at 373.15 K, Δ vap H: 40.68 kJ/mol Std entropy change of vaporization, Δ vap S o: 118.89 J/(mol·K) Entropy change of vaporization at 373.15 K, Δ vap S: 109.02 J/(mol ...
On the other hand, the molecules in liquid water are held together by relatively strong hydrogen bonds, and its enthalpy of vaporization, 40.65 kJ/mol, is more than five times the energy required to heat the same quantity of water from 0 °C to 100 °C (c p = 75.3 J/K·mol).