Question

Find the empirical formula of substance which has the following percentage composition by mass of sodium18.20 sulphur 12.7 oxygen 19.1 water of crystalisation solve

Answer 1

Explanation:

Empirical formula is therefore Na2SH20 O14

empirical mass=2×23+32+20×1+14×16=322g

Given:

Molecular mass = 322 g

∴ molecular formula =empirical formula=Na2SH20O14

Given that all the hydrogen in the compound is reset in combination with oxygen as water of crystallisation

If water of crystallization are nH 2 O then, 2n=20

or n=10

Crystallized water is 10H 2 O remaining atoms are Na 2 SO 4

therefore, the molecule is Na 2SO4.10H 2 O