Question

Suppose you are provided with a 30.86 g sample of potassium chlorate to perform this experiment. What is the mass of oxygen you expect
to release upon heating?

Answer 1

Answer:

The mass of oxygen is 12.10 g.

Explanation:

The decomposition reaction of potassium chlorate is the following:

2KClO₃(s) → 2KCl(s) + 3O₂(g)

We need to find the number of moles of KClO₃:

$\eta_{KClO_{3}} = \frac{m}{M}$

Where:

m: is the mass = 30.86 g

M: is the molar mass = 122.55 g/mol

$\eta_{KClO_{3}} = \frac{30.86 g}{122.55 g/mol} = 0.252 moles$                                      

Now, we can find the number of moles of O₂ knowing that the ratio between KClO₃ and O₂ is 2:3

$\eta_{O_{2}} = \frac{3}{2}*0.252 moles = 0.378 moles$

Finally, the mass of O₂ is:

$m = 0.378 moles*32 g/mol = 12.10 g$

Therefore, the mass of oxygen is 12.10 g.

I hope it helps you!