Physical and chemical properties of alcohol
6.1. Physical properties
Alcohol is fugacious, tasty, colorless and odorous under normal conditions. Physical and chemical properties of alcohol depend on hydroxyl (COH) group. Spectrographic studies show that in liquid form, there is a hydrogen link between the hydrogen of hydroxyl group of one molecule and the oxygen of hydroxyl group of the second molecule; however, the link is weaker than the one between water molecules.
Troton constant is the ration of molar evaporation heat to absolute boiling point under 1 atmosphere pressure. The constant for some combined ethanol molecules is about 26.9 and for individual molecules, it is 21. In table 1.4, some physical properties of alcohol are presented. Troton constant indicates evaporation entropy in 1 atmosphere pressure.
Physical properties of ethanol alcohol
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Properties
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Amount
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Freezing point (°C)
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-114.1
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Normal boiling point (°C)
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78.39
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Critical temperature (°C)
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243.1
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Critical pressure (At m)
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63
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Critical volume (Cm3/mol)
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0.167
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Zc critical compression ratio
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0.248
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d20 4 alcohol density in 20°C comparing to water density in 4°C
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0.7893
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d20 4 refractive index in 20°C (Sodium light)
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1.36143
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Surface tension in 25°C dyn/cm
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23.1400
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Viscosity (20°C) CP
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1.500
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Water solubility (20°C)
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Solubility (solution)
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Latent evaporation heat (evaporation in normal boiling point) cal/gr
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200.6
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Combustion heat(20°C) cal/gr
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25
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Specific heat cal/gr °C
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0.579
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Heat conduction j/sec.cm2
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0.0017
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Alcohol viscosity is another significant feature indicating the amount of its stickiness. The viscosity reduces as the heat increases.
Chemical properties of alcohol
The chemical formula of ethyl alcohol is C2H5OH and is soluble in water. Alcohol has the ability to dissolve lipids and this feature can be used for cleaning ground floors.
One of the significant features of alcohol is germicide characteristic which has made it be used in medical affairs as an antiseptic material.
Another important characteristic of alcohol is its burn. Ethyl alcohol, like other organic materials, burns and dioxide carbon and water remain afterwards. The alcohol burning reaction is defined as below:
As it is evident in the reaction mentioned above, alcohol burning does not produce smog and it just results in carbonic gas and water.
Chemical properties of the 96-degree medical ethylic alcohol according to Standard No. 116 are presented in the .following table
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1.8. Features of medical ethylic acohol
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Chemical properties of absolute ethylic alcohol are as the table below:
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1.9. Features of absolute alcohol according to standard No. 161
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