Practice Limiting Reactant in Chemistry

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

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Quick Recap

The reactant that is completely consumed first in a chemical reaction, thereby determining the maximum amount of product that can be formed.

If you have 10 buns and 5 patties, you can only make 5 burgers—patties are limiting.

Showing a random 20 of 50 problems.

Example 1

medium
If 4.04.0 mol of H2\text{H}_2 reacts with 1.01.0 mol of O2\text{O}_2 in the reaction 2H2+O2→2H2O2\text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O}, which is the limiting reactant?

Example 2

easy
If reactant X gives 4 mol product and reactant Y gives 6 mol product, which is limiting?

Example 3

medium
Which is limiting in A+3B→C\text{A} + 3\text{B} \rightarrow \text{C} when you have 5 mol A and 9 mol B?

Example 4

medium
For 2Al+3Cl2→2AlCl32\text{Al} + 3\text{Cl}_2 \rightarrow 2\text{AlCl}_3 with 4 mol Al and 5 mol Cl2\text{Cl}_2, how many mol of AlCl3\text{AlCl}_3 form?

Example 5

easy
In a sandwich shop, each sandwich needs 2 slices of bread and 1 slice of cheese. With 20 slices of bread and 8 slices of cheese, which is limiting?

Example 6

medium
In CH4+2O2→CO2+2H2O\text{CH}_4 + 2\text{O}_2 \rightarrow \text{CO}_2 + 2\text{H}_2\text{O}, you have 2 mol CH4\text{CH}_4 and 3 mol O2\text{O}_2. Which is limiting?

Example 7

hard
Using 2H2+O2→2H2O2\text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O} with 6 mol H2\text{H}_2 and 2 mol O2\text{O}_2, how many mol of H2\text{H}_2 are left over?

Example 8

medium
For CaCO3+2HCl→CaCl2+H2O+CO2\text{CaCO}_3 + 2\text{HCl} \rightarrow \text{CaCl}_2 + \text{H}_2\text{O} + \text{CO}_2, with 1.0 mol CaCO3\text{CaCO}_3 and 1.0 mol HCl, which is limiting?

Example 9

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In 2Al+3Cl2→2AlCl32Al + 3Cl_2 \rightarrow 2AlCl_3 with 2 mol Al and 2 mol Cl2Cl_2, which is limiting?

Example 10

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For S+O2→SO2\text{S} + \text{O}_2 \rightarrow \text{SO}_2 with 3.2 g S (M = 32.0) and 3.2 g O2\text{O}_2 (M = 32.0), which is limiting?

Example 11

easy
A recipe needs 2 eggs and 1 cup of flour per cake. You have 10 eggs and 4 cups of flour. Which ingredient is the limiting 'reactant'?

Example 12

medium
In 2H2+O2→2H2O2H_2 + O_2 \rightarrow 2H_2O with 4 g H2H_2 (M=2M=2) and 16 g O2O_2 (M=32M=32), which is limiting?

Example 13

hard
If 0.50 mol of Al\text{Al} reacts with 0.60 mol of Br2\text{Br}_2 in 2Al+3Br2→2AlBr32\text{Al} + 3\text{Br}_2 \rightarrow 2\text{AlBr}_3, how many mol of AlBr3\text{AlBr}_3 form?

Example 14

medium
In a reaction A+2B→C\text{A} + 2\text{B} \rightarrow \text{C}, if you have 33 mol of A and 44 mol of B, which is limiting?

Example 15

easy
True or false: The reactant present in the largest amount is always the limiting reactant.

Example 16

easy
Why must you find the limiting reactant before computing product?

Example 17

challenge
In 2Al+3Cl2→2AlCl32Al + 3Cl_2 \rightarrow 2AlCl_3 with 4 mol Al and 3 mol Cl2Cl_2, how much AlCl3AlCl_3 and which is in excess?

Example 18

medium
In A+2B→CA + 2B \rightarrow C with 3 mol A and 4 mol B, which is limiting and how much C?

Example 19

easy
Fill in the blank: The reactant left over after a reaction finishes is called the ____ reactant.

Example 20

medium
After running N2+3H2→2NH3\text{N}_2 + 3\text{H}_2 \rightarrow 2\text{NH}_3 with 2 mol N2\text{N}_2 and 5 mol H2\text{H}_2, how many mol of N2\text{N}_2 remain?
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