Question

What is the molecular formula of aluminum chloride containing 20.2% by mass of aluminum and 79.8% My mess of chlorine. The relative molecular mess is 267 g.

Answer 1

The molecular formula : Al₂Cl₆

Further explanation

Given

20.2% by mass of Aluminum and 79.8% by mass of Chlorine.

Required

the molecular formula

Solution

• Empirical formula

Aluminium (Ar=27 g/mol)

`\tt (20.2)/(27)=0.748`

Chlorine(Ar=35.5 g/mol)

`\tt (79.8)/(35.5)=2.248`

mol ratio Al : Cl =

`\tt (0.748)/(0.748)/ (2.248)/(0.748)=1/ 3`

So the empirical formula = AlCl₃

(Empirical formula)n=Molecular formula

(27+3.35.5)n=267

(133.5)n=267⇒n=2

The molecular formula : Al₂Cl₆