Hello student,

Here's a solution to your query :

We must calculate how many moles of potassium chlorate reacted

Use the formula moles=given mass / molar mass

The mass of the reactant in the question is 200g . The molar mass of the reactant is 158.034gmol−1

200 / 158.034=1.26555mol of the reactant.

Ratio - 2:1

Therefore, 1.26555 / 2=0.632775mol of oxygen is produced.

Answer : The mass of produced oxygen is 20.2475g.

Thanks.