Question

Calculate the amount of Potassium chloride obtained by the thermal decomposition of 12.25 kg of Potassium chlorate?

Answer 1

• 1 mole of a substance = molar mass of the substance.
• The balanced chemical equation for the decomposition of potassium chlorate (KClO₃ ) is

KClO₃(s) ⇢ 2KCl(s) + 3O₂(g)

Molecular weight of potassium chlorate KClO₃ = 122.5g/mol

Molecular weight of potassium chloride(KCl) = 74.5g/mol

Given weight of potassium chlorate is 12.25 Kg = 12.25 × 10³ g

To convert this in to moles, 122.5 g of potassium chlorate KClO₃ =1mole

Therefore 12.25 Kg of Potassium chlorate KClO₃ =$\frac{1}{122.5}$× 12.25 ×10³ =100 mole.

• Using the mole ratio from the chemical reaction, 1 mole of potassium chlorate KClO₃ produces 2 mole potassium chloride (KCl)

Therefore 100 moles of potassium chlorate KClO₃ will produce KCl = 2 × 100 moles of KCl =200mole

• Molar mass of Potassium chloride KCl =74.5g/mol

i.e., 1 mole of Potassium chloride KCl has a weight=74.5g

Therefore 200 moles of Potassium chloride KCl has weight= 200 × 74.5 = 14900g =14.9Kg