Small amounts of oxygen gas can be produced for laboratory use by heating potassium chlorate, which causes it to decompose by the following reaction: ___KClO₃(s)→ ____KCl(s)+ ___O₂(g)(unbalanced)Balance the equation, and determine the mass of oxygen that should be formed if 10.0 g of potassium chlorate decomposes.

Question

Quizplus · Accepted Answer

The balanced chemical equation is:

2KClO3(s) → 2KCl(s) + 3O2(g)

The molar mass of KClO3 is 122.55 g/mol, which means that 10.0 g of KClO3 is equivalent to:

10.0 g KClO3 × (1 mol KClO3/122.55 g KClO3) = 0.0816 mol KClO3

According to the balanced chemical equation, 2 moles of KClO3 produce 3 moles of O2. Therefore, 0.0816 mol KClO3 will produce:

(3 mol O2/2 mol KClO3) × 0.0816 mol KClO3 = 0.1224 mol O2

The molar mass of O2 is 32.00 g/mol, which means that 0.1224 mol O2 is equivalent to:

0.1224 mol O2 × (32.00 g O2/1 mol O2) = 3.92 g O2

Therefore, the correct answer is C) 3.92 g.

Small Amounts of Oxygen Gas Can Be Produced for Laboratory