Mole ratios from a balanced equation

Answer Key - Grade 10 Science Worksheet - Building Confidence

Circle the best answer, or write your answer on the line.

1. 1.

   In 2H₂ + O₂ → 2H₂O (an equation only), the coefficients are 2 for H₂ and 1 for O₂. How many moles of O₂ react with 6 mol of H₂, Ari?

   3 mol
2. 2.

   In respiration, C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O, the coefficients are 1 for glucose and 6 for O₂. How many moles of O₂ react with 2 mol of glucose, Bo?

   12 mol
3. 3.

   In photosynthesis, 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂, the coefficients are 6 for CO₂ and 1 for glucose. How many moles of glucose form from 3 mol of CO₂, Kira?

   0.5 mol
4. 4.

   In 2H₂ + O₂ → 2H₂O, what is the mole ratio of H₂ to O₂, Jun?

   • 2 mol H₂ to 2 mol O₂
   • 1 mol H₂ to 2 mol O₂
   • 2 mol H₂ to 1 mol O₂
5. 5.

   In 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂, what is the mole ratio of CO₂ to glucose, Milo?

   • 1 mol CO₂ to 6 mol glucose
   • 1 mol CO₂ to 1 mol glucose
   • 6 mol CO₂ to 1 mol glucose
6. 6.

   In 2H₂ + O₂ → 2H₂O, what does the 2 in front of H₂O mean, Noah?

   • Each water molecule has 2 H atoms
   • 2 grams of water form
   • 2 mol, or 2 molecules, of water form
7. 7.

   In 2H₂O, which number tells how many H atoms are in one molecule, Pia?

   • The small 2 after H, the subscript
   • The 2 in front, the coefficient
   • Neither: water has no hydrogen
8. 8.

   In NaHCO₃ + CH₃COOH → CH₃COONa + H₂O + CO₂, what do the missing coefficients mean, Ren?

   • Each stands for 1 g of each substance
   • Each is 0: those substances do not react
   • Each is 1: 1 mol of each substance
9. 9.

   Is 2H₂ + O₂ → 2H₂O balanced, Tala?

   • No: the 2s on each side do not match
   • Yes: 4 H and 2 O on each side
   • No: water should be written H₂O₂
10. 10.

    Is C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O balanced, Zee?

    • Yes: 6 C, 12 H and 18 O on each side
    • No: there are more molecules on the right
    • No: 1 glucose cannot make 6 CO₂