Answer to Question #291750 in Chemistry for Angelina

Question

How many grams of 

KClO3 must be decomposed to produce 91.7 g O

2

91.7 g O2?

Answer 1

Solution:

Calculate the moles of O₂:

The molar mass of O₂ is 32.0 g/mol

Hence,

Moles of O₂ = (91.7 g O₂) × (1 mol O₂ / 32.0 g O₂) = 2.8656 mol O₂

Balanced chemical equation:

2KClO₃ → 2KCl + 3O₂

According to stoichiometry:

2 mol of KClO₃ produces 3 mol of O₂

X mol of KClO₃ produces 2.8656 mol O₂:

Thus,

Moles of KClO₃ = X = ( 2.8656 mol O₂) × (2 mol KClO₃ / 3 mol O₂) = 1.91 mol KClO₃

Calculate the mass of KClO₃:

The molar mass of KClO₃ is 122.55 g/mol

Hence,

Mass of KClO₃ = (1.91 mol KClO₃) × (122.55 g KClO₃ / 1 mol KClO₃) = 234.07 g KClO₃ = 234.1 g KClO₃

Mass of KClO₃ is 234.1 grams

Answer: 234.1 grams of KClO₃ must be decomposed.