In 1808, French physicist and chemist Gay-Lussac studied one uncomplicated chemical reaction.Reacting engage two gases hydrogen chloride and ammonia, thereby to form a solid crystalline substance - ammonium chloride.The scientist noticed something unusual: that the reaction carried out, both require the same amount of gas.An excess of any of the gases just not react with other gas.When a shortage of these reactions will not proceed at all.
Gay-Lussac studied and other interactions between the gases.In all reactions observed an interesting pattern: the quantity of gases, unreacted must be either equal or differ by an integer factor.For example, a mixture of oxygen and one part of the two parts of the hydrogen forms water vapor, if in a f
lask to produce a sufficiently powerful explosion.
Gay-Lussac did not try to find out why the reactions proceed only with the gases taken in certain proportions.Avogadro studied his work and hypothesized that equal volumes of gases contain the same number of molecules.Only in this case all the molecules of the gas can react with other molecules, the excess (if any) does not react.
This hypothesis was confirmed by numerous experiments that had Avogadro.The final formulation of his law is as follows: Equal volumes of gases at the same temperature and pressure contain the same number of molecules.It is determined by the number of Avogadro Na, which is equal to 6.02 * 1023 molecules.This value is used to address the many problems of gas.This law does not work in the case of solids and liquids.In them, unlike gases observed much more powerful intermolecular forces.
Consequences of Avogadro's law
This law implies a very important statement.The molecular weight of any gas should be proportional to its density.It turns out that M = K * d, where M - molecular weight, d - density of the respective gas, and K - a factor of proportionality.
K is the same for all gases, are on an equal footing.It is about 22.4 liters / mole.This is a very important variable.It shows the volume which takes one mole of gas at standard conditions (temperature of 273 K or 0 degrees Celsius and a pressure of 760 mm Hg).It is often called the molar volume of the gas.
- law Avogadro