Practice Stoichiometric Calculations

15.0 g KClO₃ × 1 mol KClO₃122.55 g KClO₃ × 3 mol O₂2 mol KClO₃ × 32.00 g O₂1 mol O₂ = 5.88 g O₂

Problem 2 – Limiting Reagent

HCl:

25.0 g HCl × 1 mol HCl36.46 g HCl = 0.686 mol HCl

NaOH:

25.0 g NaOH × 1 mol NaOH40.00 g NaOH = 0.625 mol NaOH

1:1 ratio → NaOH is limiting.

0.625 mol NaOH × 1 mol NaCl1 mol NaOH × 58.44 g NaCl1 mol NaCl = 36.5 g NaCl

Problem 3 – Theoretical Yield

1.50 g CaCO₃ × 1 mol CaCO₃100.09 g CaCO₃ × 1 mol CO₂1 mol CaCO₃ × 44.01 g CO₂1 mol CO₂ = 0.660 g CO₂

Problem 4 – Percent Yield

Percent Yield = 15.3 g 18.0 g × 100 = 85.0%

Problem 5 – Limiting + Excess

10.0 g CO × 1 mol CO28.01 g CO = 0.357 mol CO

10.0 g O₂ × 1 mol O₂32.00 g O₂ = 0.313 mol O₂

CO is limiting.

0.357 mol CO × 1 mol CO₂1 mol CO × 44.01 g CO₂1 mol CO₂ = 15.7 g CO₂

Problem 6 – Mole to Mole + Molecules

2.00 g NaHCO₃ × 1 mol NaHCO₃84.01 g NaHCO₃ × 1 mol CO₂1 mol NaHCO₃ = 0.0238 mol CO₂

0.0238 mol CO₂ × 6.022 × 10²³ molecules1 mol = 1.43 × 10²² molecules

Problem 7 – Hydrogen Peroxide

34.0 g H₂O₂ × 1 mol H₂O₂34.02 g H₂O₂ × 1 mol O₂2 mol H₂O₂ × 32.00 g O₂1 mol O₂ = 16.0 g O₂ (theoretical)

Percent Yield = 14.0 g 16.0 g × 100 = 87.5%