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.

(i) Mass of boron in compound = 0.096 g

And, Mass of compound = 0.24 g


So, Percentage of boron = Mass of boron in compound/Mass of compound × 100


= 0.096/0.24 × 100


= 40 ……………….(1)


(ii) Mass of oxygen in compound = 0.144 g


And, Mass of compound = 0.24 g


So, Percentage of oxygen = Mass of oxygen in compound/Mass of compound × 100


= 0.144/0.24 × 100


= 60 …………..(2)


Thus, the percentage composition of the compound is: Boron = 40%; Oxygen = 60%


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