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Excess volume of the mixture of ethanol and water (volume contraction) Heat of mixing of the mixture of ethanol and water Vapor–liquid equilibrium of the mixture of ethanol and water (including azeotrope) Solid–liquid equilibrium of the mixture of ethanol and water (including eutecticum) Miscibility gap in the mixture of dodecane and ethanol
Water vapor is an invisible gas, but the clouds of condensed droplets refract and scatter the sunlight and are thus visible. Droplets of water vapor in a pan. Demonstration of evaporative cooling. When the sensor is dipped in ethanol and then taken out to evaporate, the instrument shows progressively lower temperature as the ethanol evaporates.
Differences in volatility can be observed by comparing how fast substances within a group evaporate (or sublimate in the case of solids) when exposed to the atmosphere. A highly volatile substance such as rubbing alcohol (isopropyl alcohol) will quickly evaporate, while a substance with low volatility such as vegetable oil will remain condensed ...
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]
Such a deviation suggests weaker intermolecular attraction than in the pure components, so that the molecules can be thought of as being "held in" the liquid phase less strongly than in the pure liquid. An example is the azeotrope of approximately 95% ethanol and water. Because the azeotrope's vapor pressure is higher than predicted by Raoult's ...
Temperature-dependency of the heats of vaporization for water, methanol, benzene, and acetone. In thermodynamics, the enthalpy of vaporization (symbol ∆H vap), also known as the (latent) heat of vaporization or heat of evaporation, is the amount of energy that must be added to a liquid substance to transform a quantity of that substance into a gas.
A drop of water that was vaporized almost immediately at 168 °C (334 °F) persisted for 152 seconds at 202 °C (396 °F). Lower temperatures in a boiler firebox might evaporate water more quickly as a result; compare Mpemba effect. An alternative approach was to increase the temperature beyond the Leidenfrost point.
Ethanol-filled thermometer are used in preference to mercury for meteorological measurements of minimum temperatures and can be used down to −70 °C (−94 °F). [2] The physical limitation of the ability of a thermometer to measure low temperature is the freezing point of the liquid used. Ethanol freezes at −114.9 °C (−174.82 °F).