Question

A compound made up of two element A and B has 70% and 30%. Their relative number of moles in the compound are 1.25 and 1.88 .Calculate atomic mass of element A and B

Answer 1

Answer:

Relative no. of moles of an element

Atomic mass of B = 30/1.88 = 16

Calculation of Empirical formula

Element Relative no. of moles Simplest molar ratio Simplest whole no. molar ratio

A 1.25 1.25/1.25 = 1 2

B 1.88 1.88/1.25 = 1.5 3

Empirical formula = A2B3

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 = A2B3