Mole ratios from a balanced equation

Answer Key - Grade 10 Science Worksheet - Challenge Me

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

1. 1.

   2H₂ + O₂ → 2H₂O (an equation only). H₂O has coefficient 2 and O₂ 1. How many moles of O₂ make 5 mol of water, Esme?

   2.5 mol
2. 2.

   Photosynthesis: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂. Glucose has coefficient 1 and H₂O 6. How many moles of water make 0.3 mol of glucose, Jun?

   1.8 mol
3. 3.

   Bo says 2H₂ + O₂ → 2H₂O shows 2 g of hydrogen meeting 1 g of oxygen. Which reply fits, Luz?

   • Agree: the equation lists the masses
   • Disagree: it shows 2 mol of H₂ for each 1 mol of O₂
   • Agree: the coefficients are the grams of each gas that react
4. 4.

   Kira says respiration uses 1 mol of O₂ for each mole of glucose. Which reply fits, Milo?

   • Disagree: 6 mol of O₂ for each mole of glucose
   • Agree: each substance in any equation reacts 1 to 1
   • Agree: the subscripts carry the ratio
5. 5.

   Jun says that in photosynthesis 6 g of CO₂ makes 1 g of glucose. Which reply fits, Noah?

   • Agree: 6 to 1 holds in any unit
   • Disagree: 6 mol of CO₂ makes 1 mol of glucose
   • Agree: the coefficients give the grams
6. 6.

   In 2H₂ + O₂ → 2H₂O, how many O₂ molecules react with 1.2044 × 10²⁴ H₂ molecules, Pia?

   • 1.2044 × 10²⁴
   • 2.4088 × 10²⁴
   • 6.022 × 10²³
7. 7.

   In respiration (1 glucose : 6 CO₂), how many CO₂ molecules form from 6.022 × 10²³ glucose molecules, Ren?

   • 1.0037 × 10²³
   • 6.022 × 10²³
   • 3.6132 × 10²⁴
8. 8.

   In photosynthesis (6 CO₂ : 6 O₂), how many O₂ molecules form when 3.6132 × 10²⁴ CO₂ molecules are used, Tala?

   • 6.022 × 10²³
   • 2.1679 × 10²⁵
   • 3.6132 × 10²⁴
9. 9.

   Respiration (C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O) uses 3 mol of O₂. How many moles of water form, and of glucose are used, Zee?

   • 0.5 mol of water; 3 mol of glucose
   • 3 mol of water; 3 mol of glucose
   • 3 mol of water; 0.5 mol of glucose
10. 10.

    Photosynthesis (6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂) makes 1.5 mol of O₂. How many moles of glucose form, Bo?

    • 9 mol, from 1.5 × 6
    • 0.25 mol
    • 1.5 mol, from a 1 : 1 ratio