Question

1. A 0.24 g sample of compound of oxygen and boron was found
by analysis to contain 0.096 g of boron and 0.144 g of oxygen.
Calculate the percentage composition of the compound by
weight.
11.00​

Answer 1

Explanation:

Total mass of compound = 0.24 g

Mass of boron in it = 0.096 g

Therefore % composition by weight of boron = (Mass of boron/ Total mass of compound)*100

= (0.096/0.24)*100

= 40 %

Mass of oxygen in the compound = 0.144 g

Therefore % composition by weight of oxygen = (Mass of oxygen/ Total mass of compound)*100

= (0.144/0.24)*100

= 60 %.

The compound is made up of only boron and oxygen, therefore the % composition of the componenets sum to 100% (60% + 40%)