Determine the empirical formula of this compound working correct to one decimal place

Question

A compound X consists of 4.8% carbon and 95.2% bromine by mass 

1. Determine the empirical formula of this compound working correct to one decimal place 

2. If the vapour density of the compound is 252, what is the molecular formula of the compound. 

(C = 12 ; Br = 80) (CBr₃ , C₂Br₆ ).

Answer 1

Empirical formula = CBr₃

V.D = 252

Empirical formula = CBr₃

Empirical molecular mass 

= 12 + 80 x 3 = 252

Molecular formula = 2 x Emp. formula = 2(CBr₃)

Molecular formula = 2 x Emp. formula = 2(CBr₃) = C₂Br₆.