How are the following properties of a gas measured:
(i) Mass   (ii) Volume?
(i) Mass: The mass of a gas can be determined by weighing the container containing the gas and then emptying the container by taking out the gas and weighing the empty container gain. The difference between the two weights gives the mass of the gas. The mass of the gas can be converted into moles by using the following relation:
The moles can be converted into number of molecules by using the relation
1 Mole = 6·023 × 1023 molecules.
(ii) Volume: Since a gas occupies the entire space of the container available to it, the volume of the gas is the same as the volume of the container.
In S.I. units volume is measured in cubic metre (m3). 1m3Â = 103Â dm3Â = 106Â cm3
A manometer is connected to a gas containing bulb. The open arm reads 43.7 cm where the arm connected to the bulb reads 15.6 cm. If the barometric pressure is 743 nm mercury what is the pressure of the gas in a bar?