Calculate the mass of KCIO3 required to produce 6.72 litre of O2 at STP. [atomic masses of K = 39, Cl = 35.5, O = 16].

Question

O₂ is evolved by heating KClO₃ using MnO₂ as a catalyst

Calculate the mass of KCIO₃ required to produce 6.72 litre of O₂ at STP. [atomic masses of K = 39, Cl = 35.5, O = 16].

Answer 1

Molecular wt. of KClO₃ = 39 + 35.5 + 16 x 3  = 122.5

3 x 22.4 l of oxygen is produced from 2 x 122.5 g of KClO₃ 

6.72 l of oxygen is produced from (2 x 122.5 x 6.72)/(3 x 22.4) = 24.5 g

24.5 g of KClO₃ is required to produce 6.72 l of O₂ at STP.