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The gas constant R is defined as the Avogadro constant N A multiplied by the Boltzmann constant k (or k B): = = 6.022 140 76 × 10 23 mol −1 × 1.380 649 × 10 −23 J⋅K −1 = 8.314 462 618 153 24 J⋅K −1 ⋅mol −1. Since the 2019 revision of the SI, both N A and k are defined with exact numerical values when expressed in SI units. [2]
R is the ideal gas constant. M is the molar mass of the solvent. T b is boiling point of the pure solvent in kelvin. ΔH vap is the molar enthalpy of vaporization of the solvent. Through the procedure called ebullioscopy, a known constant can be used to calculate an unknown molar mass. The term ebullioscopy means "boiling measurement" in Latin.
Technical literature can be confusing because many authors fail to explain whether they are using the ideal gas constant R, or the specific gas constant R s. The relationship between the two constants is R s = R / m, where m is the molecular mass of the gas. The US Standard Atmosphere (USSA) uses 8.31432 m 3 ·Pa/(mol·K) as the value of R.
Similar to the Kelvin scale, which was first proposed in 1848, [1] zero on the Rankine scale is absolute zero, but a temperature difference of one Rankine degree (°R or °Ra) is defined as equal to one Fahrenheit degree, rather than the Celsius degree used on the Kelvin scale.
184.9 K (−88.2 °C), ? Pa Critical point: 508.7 K (235.6 °C), 5370 kPa Std enthalpy change of fusion, Δ fus H o: 5.28 kJ/mol Std entropy change of fusion, Δ fus S o: 28.6 J/(mol·K) Std enthalpy change of vaporization, Δ vap H o: 44.0 kJ/mol Std entropy change of vaporization, Δ vap S o: 124 J/(mol·K) Solid properties Std enthalpy ...
J/(mol K) Heat capacity, c p? J/(mol K) Liquid properties Std enthalpy change of formation, Δ f H o liquid –25.4 kJ/mol Standard molar entropy, S o liquid: 253.80 J/(mol K) Enthalpy of combustion, Δ c H o –4549 kJ/mol Heat capacity, c p: 184.5 J/(mol K) at 25 °C Gas properties Std enthalpy change of formation, Δ f H o gas: 17.2 kJ/mol ...
The K factor or characterization factor is defined from Rankine boiling temperature °R=1.8Tb[k] and relative to water density ρ at 60°F: . K(UOP) = / The K factor is a systematic way of classifying a crude oil according to its paraffinic, naphthenic, intermediate or aromatic nature. 12.5 or higher indicate a crude oil of predominantly paraffinic constituents, while 10 or lower indicate a ...
The ideal kinetic resolution is that in which only one enantiomer reacts, i.e. k R >>k S. The selectivity (s) of a kinetic resolution is related to the rate constants of the reaction of the R and S enantiomers, k R and k S respectively, by s=k R /k S, for k R >k S. This selectivity can also be referred to as the relative rates of reaction.