Question

A sample of KClO3 yielded448 ml of oxygen gas at ntp. what will be the weight of KClO3 original taken?

Answer 1

HELLO THERE!

Molar mass of KClO₃ = 39 + 35.5 + 3x16 = 122.5 g mol⁻¹

Molecular weight of Oxygen = 32

Reaction:

2KClO₃ ----> 2KCl + 3O₂

3x22400mL of Oxygen is yielded by 2x122.5g of KClO₃

Hence, 448 mL of oxygen is yielded by:

$\frac{2\times122.5}{3\times22400}\times448 \\\\= \frac{109760}{67200} \\\\= 1.63g$

Hence, 1.63 grams of Potassium chlorate was originally taken.