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Molal freezing point constant: ... Gas properties ... Thermophysical properties of mixtures of ethanol with water and dodecane
Freezing point (°C) K f (°C⋅kg/mol) Data source; Aniline: ... Ethanol: 0.78 78.4 1.22 –114.6 –1.99 ... Water: 100.00 0.512 0.00
At atmospheric pressure, mixtures of ethanol and water form an azeotrope at about 89.4 mol% ethanol (95.6% ethanol by mass, [83] 97% alcohol by volume), with a boiling point of 351.3 K (78.1 °C). [84] At lower pressure, the composition of the ethanol-water azeotrope shifts to more ethanol-rich mixtures. [85]
As water or ethylene glycol freeze out of the mixture, the concentration of ethanol/methanol increases. This leads to a new, lower freezing point. With dry ice, these baths will never freeze solid, as pure methanol and ethanol both freeze below −78 °C (−98 °C and −114 °C respectively).
The temperatures and mixing ratios of these phase equilibria can be read from the phase diagram of ethanol and water. The maximum enrichment of ethanol in the liquid phase is reached at the eutectic point of ethanol and water, approximately 92.4 weight-% ethanol at -123 °C. [3] The best-known freeze-distilled beverages are applejack and ice beer.
Triple point: 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 ...
A well-known example of a positive azeotrope is an ethanol–water mixture (obtained by fermentation of sugars) consisting of 95.63% ethanol and 4.37% water (by mass), which boils at 78.2 °C. [10] Ethanol boils at 78.4 °C, water boils at 100 °C, but the azeotrope boils at 78.2 °C, which is lower than either of its constituents. [11]
In the above equation, T F is the normal freezing point of the pure solvent (273 K for water, for example); a liq is the activity of the solvent in the solution (water activity for aqueous solution); ΔH fus T F is the enthalpy change of fusion of the pure solvent at T F, which is 333.6 J/g for water at 273 K; ΔC fus p is the difference ...