Question

(i) 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.

(ii) Convert into mole. (a) 20 g of water (b) 22 g of carbon dioxide.​

Answer 1

Mass of the given sample compound = 0.24g

Mass of boron in the given sample compound = 0.096g

Mass of oxygen in the given sample compound = 0.144g

% composition of compound = % of boron and % of oxygen

Therefore % of boron = (mass of boron)/(mass of the sample compound) x 100

= 40%

Therefore % of oxygen = (mass of oxygen) / (mass of the sample compound) x 100

= 60%