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Alcohol amount in the aqueous alcohol solution

Defines the mass and volume fraction of ethanol in the solution of two liquids with different levels of alcohol.
Anton2015-07-27 19:28:43

Responding to the request I publish this calculator that calculates the amount of pure alcohol in the solution of two liquids with different amounts of ethyl alcohol and water.I allowed myself to slightly deviate from the requirements of the original request, where people wanted to mix pure alcohol with water, and added the parameter for each mixed fluid setting the amount of alcohol in it. That allows to mix not only the water with alcohol but use it for other fluids containing alcohol. To determine the solution with clean water, it is necessary to enter a zero in the column for the volume fraction of alcohol of the one liquids. Details of calculation and a bit of theory and history can be found just below the calculator:

The percentage of ethyl alcohol in the aqueous-alcoholic solutionCreative Commons Attribution/Share-Alike License 3.0 (Unported)
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History

In the 19th century, at least one-third of the budget of the Russian Empire were excise taxes on alcoholic beverages. The excise tax is calculated, depending on the strength of the drink (amount of pure alcohol). Therefore, the task of determining the amount of pure alcohol was at the level of national importance.As long as this topic was not connected to science, beverage strength was determined with quite interesting methods. For example, for a long time, the most common type of strong wine in Russia was the so-called polugar (38% of alcohol). The way of proving the quality of Polugar was simple - set it on fire and it will burn until the half of it's amount burns out.- if you set fire to Polugar, it should burn until the half of it's volume is burned out.
Obviously, burning alcohol to determine its strength is not convenient, so the next step in the Russian history of vodka industry was to attract the Western experience: to determine the amount of alcohol began to use areometers (alcoholmeters) - the devices to determine the content alcohol, which was already been extensively used in the leading Western countries.

Alcoholmeters of the 19th century created for the use in the mild climate of Western countries, gave the poor results in the conditions of Russian temperatures besides there were different methods of measuring the volume and strength of alcohol. These premises served as an incentive to activation of the domestic science in the studies of solution properties of alcohols.

Theory

Mendeleev held a serious study of aqueous-alcoholic solutions. While working on his doctoral dissertation Mendeleev studied the change of specific mass of the alcohol solution with the concentration and temperature.
The volume (density) of the aqueous alcohol solution, as well as any other fluid, is temperature dependent.The density of the solution decreases with increase in temperature (the volume increases), the change is not linear, as well as the behavior of water density with the temperature change. It is known that the maximum density of water is at a temperature of about 4 ° C and then with any change in temperature the density decreases.
It also appears that the solution density nonlinearly varies with the alcohol concentration change. Surprising fact: the volume of water and alcohol separately are almost always greater than the volume of the solution obtained by mixing these components. The reduction of the volume of aqueous-alcohol solution, now known as contraction, reaches its maximum when the alcohol concentration in the solution is 50 to 60 percent by weight, see. the graph:

Dependence of the density of hydroalcoholic solution on the temperature and concentration of the alcoholCreative Commons Attribution/Share-Alike License 3.0 (Unported)
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Density graph of hydroalcoholic solution:

The clear pattern in the change of the volume has not been identified. Instead, Mendeleev created the approximate formulas that are used to create the tables of density dependence of alcohol solutions of mass or volume fraction and also the temperature.At present, these tables are used everywhere in the alcohol industry.
Our calculator calculates the mass and volume fraction of ethyl alcohol in the aqueous-alcoholic solution of 2 liquids with different alcohol content by linear approximation by aqueous-alcohol solution tables of the mass and volume concentration and temperature (see Table 1 and Table 2 of [1]).

The amount of liquid can be set as the weight in grams or as the volume in milliliters. The volume of liquid depends on the temperature, so for the case of setting the number of fluid through the volume, it is necessary to enter the temperature at which this volume is valid. Alcohol amount is usually expressed as a percentage of volume (% vol) that is not an unambiguous value without the temperature info (if not specified, it usually refers to the temperature of 20 ° C). It would be much more accurate to indicate the amount in percentage by weight, which does not depend on temperature. Alas, traditions are very difficult to brake.
Very few people will be able to accept the fact that vodka would be immediately "less strong". In fact, 40% volume percent at the temperature of 20 ° C is only 33% weight percent. Nobody will be reducing the strength of such a strategic beverage voluntarily :)

Sources:
1) Tables for determining ethanol amount in the aqueous-alcoholic solutions. Volume I. Moscow Publisher IPC standards.
2) Л.Б. Бондаренко Из истории русской спиртометрии

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