A 0.24 g sample of a 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.

Given,

Mass of the sample compound = 0.24 g,

mass of boron = 0.096 g,

mass of oxygen = 0.144 g

To calculate the percentage composition of the compound,

Percentage of boron :

= $\dfrac{\text{mass of boron}}{\text{mass of the compound}}$ x 100

= $\dfrac{0.096}{0.24}$ x 100

= 40%

Percentage of oxygen

= $\dfrac{\text{mass of oxygen}}{\text{mass of the compound}}$ x 100

= $\dfrac{0.144}{0.24}$ x 100

= 60%

Hence, percentage of boron = 40% and percentage of oxygen = 60% in the compound.