Question

The following equation is one way to prepare oxygen in a lab. 2KClO3 → 2KCl + 3O2 Molar mass Info: MM O2 = 32 g/mol MM KCl = 74.55 g/mol MM KClO3 = 122.55 g/mol If 25.6 g of KCl are produced, then how many moles of KClO3 were consumed?

0.209 mol
0.687 mol
0.343 mol
0.172 mol

Answer 1

The moles of KClO₃ that were consumed is 0.343 moles

calculation

2KClO₃ → 2KCl +3O₂

step 1: find the moles KCl

moles = mass÷ molar mass

25.6 g÷74.55 g/mol =0.343 moles

Step 2 : use the mole ratio to determine the moles KClO₃

from equation above KClO₃ : KCl is 2:2 =1:1

therefore the moles KClO₃ = 0.343 moles