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)

$\tt \dfrac{20.2}{27}=0.748$

Chlorine(Ar=35.5 g/mol)

$\tt \dfrac{79.8}{35.5}=2.248$

mol ratio Al : Cl =

$\tt \dfrac{0.748}{0.748}\div \dfrac{2.248}{0.748}=1\div 3$

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