Find the limiting reactant

Answer Key - Grade 10 Science Worksheet

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

1. 1.

   In 2H₂ + O₂ → 2H₂O (an equation only), 6 mol of H₂ meets 2 mol of O₂. How many moles of water can form, Bo?

   4 mol
2. 2.

   In 2H₂ + O₂ → 2H₂O (an equation only), 5 mol of H₂ meets 1.5 mol of O₂. How many moles of water can form, Esme?

   3 mol
3. 3.

   In 2H₂ + O₂ → 2H₂O (an equation only), 10 mol of H₂ meets 3 mol of O₂. How many moles of water can form, Jun?

   6 mol
4. 4.

   16.80 g of baking soda (84.01 g/mol) meets 15.015 g of vinegar acid (60.06 g/mol), 1 : 1. Which is limiting, Kira?

   • The acid, since 15.015 g is less than 16.80 g
   • Neither: 1 : 1 means both run out
   • The baking soda: 0.2 mol against 0.25 mol
5. 5.

   In 2H₂ + O₂ → 2H₂O, 4.04 g of H₂ (2.02 g/mol) meets 16.00 g of O₂ (32.00 g/mol). Which is limiting, Milo?

   • Neither: they are in a 2 : 1 ratio
   • The H₂, since 4.04 g is less than 16.00 g
   • The O₂: 0.5 mol, but 2 mol of H₂ needs 1 mol
6. 6.

   Each sandwich needs 2 slices of bread and 1 slice of cheese. With 10 bread and 7 cheese, how many sandwiches, and what is left, Noah?

   • 10 sandwiches, using each slice of bread
   • 5 sandwiches, with 2 cheese slices left
   • 7 sandwiches, using each cheese slice
7. 7.

   Each tricycle needs 1 seat and 3 wheels. With 6 seats and 15 wheels, how many tricycles can be built, Pia?

   • 6, since there are 6 seats
   • 5, since 15 wheels ÷ 3 = 5
   • 15, one for each wheel
8. 8.

   In 2H₂ + O₂ → 2H₂O, 6 mol of H₂ meets 2 mol of O₂. How much H₂ is left over, Tala?

   • 2 mol of H₂
   • 0 mol of H₂
   • 4 mol of H₂
9. 9.

   Respiration: 0.5 mol of glucose meets 4 mol of O₂. How much O₂ is left over, Zee?

   • 1 mol of O₂
   • 3 mol of O₂
   • 3.5 mol of O₂
10. 10.

    0.2 mol of baking soda meets 0.25 mol of vinegar acid, 1 : 1. How much acid is left over, Ari?

    • 0.2 mol of acid
    • 0.25 mol of acid
    • 0.05 mol of acid