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 15.0 g of potassium chlorate decomposes.

Question

Quizplus · Accepted Answer

The balanced equation is:
2KClO3(s) → 2KCl(s) + 3O2(g)
The molar mass of KClO3 is 122.55 g/mol.
Moles of KClO3 = 15.0 g / 122.55 g/mol = 0.1224 mol
According to the balanced equation, every 2 moles of KClO3 will produce 3 moles of O2.
Moles of O2 = (3/2) x 0.1224 mol = 0.1836 mol
The molar mass of O2 is 32.00 g/mol.
Mass of O2 = 0.1836 mol x 32.00 g/mol = 5.87 g
Therefore, the mass of oxygen that should be formed if 15.0 g of potassium chlorate decomposes is 5.88 g. The best choice is D.

Small Amounts of Oxygen Gas Can Be Produced for Laboratory