Question

A compound made up of two elements a and b has a = 70%, b = 30%. Their relative number of moles in the compound is 1.25 and 1.88, calculate : (i) atomic masses of the elements a and b (ii) molecular formula of the compound , if its molecular mass is found to be 160.

Answer 1

Answer:

Explanation:

Relative number of moles of an element = % of the element / atomic mass

or atomic mass = % of element / relative number of moles

Atomic mass of A = 70 / 1,25 = 56

and Atomic mass of B = 30 / 1.88 =16

Empirical formula = $A _{ 2 }$$B _{ 3 } $

Calculation of molecular formula

Empirical formula mass = 2 x 56 + 3 x 16 = 160

n = molecular mass / empirical formula mass = 160/160 = 1

Molecular formula = $A _{ 2 }$$B _{ 3