Avogadro's law

Avogadro's law (sometimes referred to as Avogadro's hypothesis or Avogadro's principle) is an experimental gas law relating volume of a gas to the amount of substance of gas present. A modern statement of Avogadro's law is:

Avogadro's law states that, "equal volumes of all gases, at the same temperature and pressure, have the same number of molecules".

For a given mass of an ideal gas, the volume and amount (moles) of the gas are directly proportional if the temperature and pressure are constant.

which can be written as:

or

The equation shows that, as the number of moles of gas increases, the volume of the gas also increases in proportion. Similarly, if the number of moles of gas is decreased, then the volume also decreases. Thus, the number of molecules or atoms in a specific volume of ideal gas is independent of their size or the molar mass of the gas.

The law is named after Amedeo Avogadro who, in 1811, hypothesized that two given samples of an ideal gas, of the same volume and at the same temperature and pressure, contain the same number of molecules. As an example, equal volumes of molecular hydrogen and nitrogen contain the same number of molecules when they are at the same temperature and pressure, and observe ideal gas behavior. In practice, real gases show small deviations from the ideal behavior and the law holds only approximately, but is still a useful approximation for scientists.

1. Explain the following formula:

1. Write definitions of the following terms: gas, ideal gas, molar mass, hydrogen, nitrogen.

Физика және математика кафедрасының отырысында қаралып, бекітілген.

Хаттама № «7» __18_____ ____03______ 2015 ж.

Кафедра меңгерушісі:____________ Кульжумиева А.А.

Факультеттің ОӘК отырысында қаралып, бекітілген.

Хаттама № «7» __19____ ____03_____ 2015 ж.

Факультеттің ОӘК төрағасы: _________ Иксебаева Ж.С.

М. Өтемісов атындағы Батыс Қазақстан мемлекеттік университеті

Факультет: физика-математика

Кафедра: физика және Физика

Шифр, мамандық: 5В011000 – Физика

Пән: Кәсіби бағытталған шетел тілі

Билет №11

1. Read and retell the text: