To calculate the number of moles of a gaseous substance in a certain volume, we use the relationship that one mole of any gaseous substance under NTP conditions occupies 22.4 liter (L), or 22400 ml of volume. Let,

Volume of the gaseous substances at NTP= VL

Molar volume under NTP= 22.4 L/mol

So, No. of moles of the substances in V litre

ADVERTISEMENTS:

= Volume (in litres) of the substance at NTP/ 22.4 litre/mol

= V litre / 22.4 litre/ mol =V/22.4 mol

And No. of molecules in Very litre of a gas

= V/22.4 mol× 6.023 × 1023 molecules / mol

ADVERTISEMENTS:

= V/ 22.4× 6.023 × 1023 molecules