Suppose a chemist has chosen `10^(20)` as the number of particles in a mole. What would be the molecular mass of oxygen gas ?

Answer

`5.31 xx 10^(-3) g`

Explanation

`6.022 xx 10^(23)` molecules of oxygen weigh = 32 g
1.0 molecule of oxygen weighs `= (32)/(6.022xx10^(23))=5.31xx10^(-23)g`
`:.` Mass of `10^(20)` molecules of oxygen `= 5.31 xx 10^(-23) xx 10^(20) = 5.31 xx 10^(-3)g`.