Question

How many molecules and atoms of oxygen are there in 5.6 litres oxygen?

Answer 1

At NTP , one mole of a gas occupies a volume of 22.4 L .
Also we know that one mole of a gas contains avogadro number of molecules and it contains atoms equal to the product of number of molecules and atomicity .

The atomicity of oxygen is 2 , so 1 mole of oxygen contains atoms equal to 2 times the number of molecules

Therefore we can say that 22.4 L of Oxygen contains = 6.023 * 10^(23) molecules

1 L of Oxygen contains = 6.023 * 10^(23)/22.4 molecules

5.6 L of Oxygen contains = 6.023 * 10^(23) * 5.6/22.4 molecules

5.6 L of Oxygen contains = 6.023 * 10^(23)/4 molecules

5.6 L of Oxygen contains = 1.50575 * 10^(23) molecules

Therefore , 5.6 L of Oxygen contains = 1.50575 * 10^(23) * 2 atoms