Question

Oxygen is evolved by heating KClO3 using MnO2 as catalyst; 2KClO3 2KCl + 3O2 (i) Calculate the mass of KClO3 required to produce 6.72 litres of O2 at S.T.P. [Atomic mass of K=39; Cl=35.5; O=16] (ii) Calculate the number of moles of oxygen present in the above volume and also the number of molecules.

Answer 1

2KClO

3

MnO

2

2KCl+3O

2

Moles of oxygen =

22.4

6.72

=0.3

2 moles of KClO

3

will produce 3 moles of O

2

.

0.3 moles of oxygen will be produced by

3

2

×0.3=0.2 moles of chlorate.

Hence, mass of KClO

3

required =0.2×122.5=24.5g .

Answer 2

Explanation:

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