Avogadro’s Law Definition

Introduction:

The ratios of the volumes and the ratios of the molecules of reactant and product gases are identical. Gay Lussac who worked on the volume of the gases for a long time could not point out this relationship. It was an Italian Professor of Physics Avogadro who traced out this relationship and derived a law known as Avogadro’s law.

Avogadro’s Law Definition:

This law states as:

Statement:

“Equal volume of all the gases at the same temperature and pressure contain equal number of molecules.”

Avogadro’s Constant=   6.02X10²³ Molecules in 1 mole of gas at STP with 22.414 dm³ of Volume

Avogadro’s Law Equation/Formula:

Since equal number of moles of different gases contain equal number of molecules, which in turn occupy equal volumes at the same temperature and pressure, therefore,

 V  n   (At constant T and P)

It means one mole of all gases occupy the same volume at the same temperature and pressure.

Avogadro’s Law Examples:

At STP one mole of a gas occupies 22.4 dm³ volume.

1 mole of O₂ = 6.02×10²³ molecules = 22.4 dm³ volume at STP

1 mole of CO₂ = 6.02×10²³ molecules = 22.4 dm³ volume at STP

1 mole of N₂ = 6.02×10²³ molecules = 22.4 dm³ volume at STP

1 mole of H₂ = 6.02×10²³ molecules = 22.4 dm³ volume at STP