Question

1. potassium chlorate decomposed into potassium chloride and oxygen gas.

$2kclo_3\
ightarrow 2 kcl + 3o_2$
how many grams of oxygen gas will be given off from 50.0 grams of potassium chlorate?
options: 19.7 grams, 9.84 grams, 33.3 grams, 75.0 grams

Explanation:

Step1: Calculate molar mass of \(KClO_3\)

Molar mass of \(K = 39.10\ g/mol\), \(Cl = 35.45\ g/mol\), \(O = 16.00\ g/mol\).
Molar mass of \(KClO_3 = 39.10 + 35.45 + 3\times16.00 = 122.55\ g/mol\).

Step2: Find moles of \(KClO_3\)

Given mass of \(KClO_3 = 50.0\ g\).
Moles of \(KClO_3 = \frac{50.0\ g}{122.55\ g/mol} \approx 0.408\ mol\).

Step3: Relate moles of \(KClO_3\) to \(O_2\)

From reaction: \(2\ mol\ KClO_3
ightarrow 3\ mol\ O_2\).
Moles of \(O_2 = 0.408\ mol\ KClO_3 \times \frac{3\ mol\ O_2}{2\ mol\ KClO_3} \approx 0.612\ mol\).

Step4: Calculate mass of \(O_2\)

Molar mass of \(O_2 = 32.00\ g/mol\).
Mass of \(O_2 = 0.612\ mol \times 32.00\ g/mol \approx 19.7\ g\).

Answer:

19.7 grams