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

Given, Mass of the sample compound = 0.24g, mass of boron = 0.096g, mass of oxygen = 0.144g

\( Percentage \ of \ boron = \) \( mass \ of \ boron \over mass \ of \ the \ compound \) \( × 100 \) \( = \) \( 0.096 \over 0.24 \) × 100 = 40%

Percentage of oxygen = 100 – Percentage of boron

= 100 – 40 = 60%