Question

The weight of a pure sample of kclo3 to be decomposed in order to get 0.96g of o2 is

Answer 1

Equation:

2KClO3 → 2KCl + 3O2

2mol KClO3 will produce 3 mol O2

You want to produce 0.96g O2:

Molar mass O2 = 32g/mol

0.96 g = 0.96/32 = 0.03mol O2

You require 0.03*2/3 = 0.02 mol KClO3

1mol KClO3 = 6.022*10^23 formula units

0.02 mol KClO3 = (6.022*10^23)*0.02 = 1.2*10^22 formula units. As the answer is in the text book.