The molecular mass of a substance is numerically equal to the mass of 1 mole of its molecules. Since 1 mole of molecules is equal lto `6.022 xx 10^(23)` molecules, it means that the molecular mass of a substance is numerically equal to the mass of its `6.022 xx 10^(23)` molecules . In this problem we have been given the absolute mass of 1 molecule of the substance, so all that we have to do is to find out the mass of its `6.022 xx 10^(23)` molecules.
Now, Mass of 1 molecule of substance `= 5.32 xx 10^(-23) g`
So, Mass of `6.022 xx 10^(23)` molecules of substance `= 5.32 xx 10^(-23) xx 6.022 xx 10^(23)`
`= 32 g`
Thus, the molecular mass of the given substance is 32 u. The substance having a molecular mass of 32 u is oxygen , having the formula `O_(2)`.
