Limiting Reactants Worksheet

Question 1

In 2H₂ + O₂ → 2H₂O, a mixture has 2.00 mol H₂ and 2.00 mol O₂. Which reactant is limiting?

1. H₂
2. O₂
3. Both are present in the required ratio.
4. The product is limiting.

Question 2

For 2H₂ + O₂ → 2H₂O, 4.00 mol H₂ reacts with 3.00 mol O₂. Calculate the moles of O₂ left after the limiting reactant is used up.

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Question 3

Explain why the reactant with fewer moles is not automatically the limiting reactant.

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Question 4

Which starting amounts match the exact ratio for N₂ + 3H₂ → 2NH₃?

1. 1 mol N₂ and 1 mol H₂
2. 1 mol N₂ and 3 mol H₂
3. 3 mol N₂ and 1 mol H₂
4. 3 mol N₂ and 2 mol H₂

Question 5

Which reactant is limiting in mixture Q?

1. Al
2. O₂
3. Both amounts match the exact ratio.
4. Al₂O₃

Question 6

Calculate how much Al₂O₃ forms from mixture Q. Use the limiting reactant and its balanced ratio.

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Question 7

How much O₂ remains after mixture P reacts?

1. 0.0 mol
2. 2.0 mol
3. 3.0 mol
4. 6.0 mol

Question 8

Use the balanced ratio to explain whether mixture R leaves any reactant in excess.

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