Gaza. Laws of Bojlja and Charles

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Zakony Bojlja and Charles can be united in one general for all gases the law expressed by all known equation

V/T=const

Where T - the absolute temperature measured on a scale of Calvin; and V cоответственно pressure and gas volume; const - a constant.

This equation in physics textbooks usually formulate so primitively, without an explanation of its sense that it speaks to beginning physicists a little. Meanwhile the equation of a condition of gas represents the remarkable result which does not have analogies in any other area physicists.

The Constant can be measured in the right member of equation of a condition for various gases, but at measurement it is necessary to start with standard conditions, we will tell to take one gramme of gas at the pressure equal to one atmosphere (760 mm of a mercury column), and at temperature 273 To. In this case we will receive value of a constant, characteristic for the taken gas. But constants for various gases are in communication with each other, for as we know already, volume of the given weight of gas inversely proportional to its molecular weight. If to consider not individual weight, and the weight proportional to molecular weight the constant in the equation of a condition of gas appears same for all gases. Therefore we will accept as standard weight of gas in the grammes, numerically equal to molecular weight, that is one gramme-molecule. It means a choice of standard volume of the gas equal of 22,4 litres. It is easy to see that at standard pressure, temperature and volume the constant will depend only on these standard sizes, instead of from any characteristics of the taken material. We can write down, thus, the equation of a condition in the form of

pV=RT,

Where R has the same value for all gases. This equation - the first of remarkable generalisations in the physicist with which help of property of the whole class of substances are expressed through the same basic sizes. To it - the physics also aspires to a finding of the general laws which are not dependent on those features or other substances. Gases, being essentially simple by the nature, have set the first example of such generalisation.