Find the limiting reactant

Answer Key - Grade 10 Science Worksheet - Building Confidence

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

1. 1.

   A bike shop has 9 frames and 14 wheels. Each bike needs 1 frame and 2 wheels. How many bikes can be built, Bo?

   7 bikes
2. 2.

   A bike shop has 12 frames and 20 wheels. Each bike needs 1 frame and 2 wheels. How many bikes can be built, Kira?

   10 bikes
3. 3.

   With 8 frames and 10 wheels, and 1 frame + 2 wheels per bike, which part runs out first, Jun?

   • The frames, since there are fewer of them
   • The wheels: 10 wheels make 5 bikes
   • Neither: they run out together
4. 4.

   In 2H₂ + O₂ → 2H₂O (an equation only), 4 mol of H₂ meets 3 mol of O₂. Which runs out first, Luz?

   • Neither: 4 and 3 are close enough
   • The O₂, since there is less of it
   • The H₂: 4 mol needs just 2 mol of O₂
5. 5.

   Respiration: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O. 1 mol of glucose meets 3 mol of O₂. Which runs out first, Milo?

   • The glucose, since there is less of it
   • Neither: each has some left
   • The O₂: 1 mol of glucose needs 6 mol
6. 6.

   In 2H₂ + O₂ → 2H₂O, 6 mol of H₂ and 2 mol of O₂ react. Divide each by its coefficient. Which is limiting, Noah?

   • H₂: it has the larger coefficient
   • O₂: 2 ÷ 1 = 2 is less than 6 ÷ 2 = 3
   • H₂: 6 ÷ 2 = 3 is the larger result
7. 7.

   Baking soda (0.3 mol) and vinegar acid (0.2 mol) react 1 : 1. Which is limiting, Ren?

   • Neither: the 1 : 1 ratio means both run out
   • The baking soda, since it fizzes away
   • The acid: 0.2 mol runs out at 1 : 1
8. 8.

   8 frames and 10 wheels make 5 bikes. How many frames are left over, Tala?

   • 0 frames: each frame is used
   • 3 frames
   • 5 frames, one for each bike
9. 9.

   In 2H₂ + O₂ → 2H₂O, 4 mol of H₂ and 3 mol of O₂ react. How much O₂ is left over, Zee?

   • 3 mol of O₂, as the O₂ does not react
   • 0 mol: both are used up
   • 1 mol of O₂
10. 10.

    Respiration: 1 mol of glucose and 3 mol of O₂ react. How much glucose is left over, Esme?

    • 0 mol: the glucose is used up
    • 0.5 mol of glucose
    • 0.83 mol, from 1 − 1 ÷ 6