Any ideal gas can be characterized several parameters: temperature, volume, pressure. The ratio establishing connection between these sizes is called the equation of a condition of gas.
Instruction
1. It was experimentally established that at a constant temperature of P1V1=P2V2, or that the same, PV=const (Boyle-Mariotta's law). With a constant pressure constant is a volume relation to temperature: V/T=const (Gay-Lussac's law). If to record the volume, then P/T=const (Charles law). Combination of these three laws gives the universal gas law which says that PV/T=const. This equation was established by the French physicist B. Klapeyron in 1834.
2. The value of a constant is defined only by amount of substance of gas. D.I. Mendeleyev in 1874 removed the equation for one asking. So he received value of a universal gas constant: J R=8.314 / (molk). So, PV=RT. In case of any amount of gas ν PV=νRT. The amount of substance can be found from the weight relation to molar weight: ν=m/M.
3. Molar weight is in number equal to relative molecular. The last can be found from Mendeleyev's table, it is specified in an element cell, as a rule, below. A molecular lot of connection is equal to the sum of molecular mass of the elements entering it. In case of raznovalentny atoms the multiplication by the index is required. For example, M (N2O) of =14∙2+16=28+16=44 g/mol.
4. Normal conditions for gases it is considered to be pressure of P0 =1 atm = 101, 325 kPa, temperature of T0=273.15 K = 0 °C. Now it is possible to find the volume of one of gas under normal conditions: L/mol Vm=RT/P0=8,314∙273,15/101,325=22,413. This table value is molar volume.
5. Under normal conditions the amount of substance is equal to the gas volume relation to molar volume: ν=V/Vm. Under any conditions it is necessary to use directly Mendeleyev-Klapeyrona's equation: ν=PV/RT.
6. So that to find gas volume under normal conditions, it is necessary to increase amount of substance (number of moths) of this gas by the molar volume equal to 22.4 l/mol. The return operation can be found amount of substance from the set volume.