Practice Stoichiometry in Chemistry

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

Worksheet PDF Free Answer-key PDF Family

Quick Recap

The branch of chemistry that uses balanced chemical equations and mole ratios to calculate the precise quantities of reactants consumed and products formed in chemical.

Using the recipe (balanced equation) to figure out how much of each ingredient you need.

Showing a random 20 of 50 problems.

Example 1

easy
2H2+O2→2H2O2\text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O}. Molar mass H2_2 = 2 g/mol. Mass of H2\text{H}_2 needed to react with 16 g O2_2? (MO2=32M_{\text{O}_2}=32)

Example 2

easy
N2+3H2→2NH3\text{N}_2 + 3\text{H}_2 \rightarrow 2\text{NH}_3. Moles NH3_3 from 0.5 mol N2_2 (excess H2_2)?

Example 3

hard
HCl+NaOH→NaCl+H2O\text{HCl} + \text{NaOH} \rightarrow \text{NaCl} + \text{H}_2\text{O}. Volume of 0.250 M0.250\,\text{M} NaOH needed to neutralize 25.0 mL25.0\,\text{mL} of 0.100 M0.100\,\text{M} HCl?

Example 4

medium
Fe2O3+3CO→2Fe+3CO2\text{Fe}_2\text{O}_3 + 3\text{CO} \rightarrow 2\text{Fe} + 3\text{CO}_2. Mass Fe from 159.7 g Fe2O3159.7\,\text{g Fe}_2\text{O}_3? (M=159.7M=159.7, MFe=55.85M_{\text{Fe}}=55.85)

Example 5

medium
How many moles of H2O\text{H}_2\text{O} are produced when 3.03.0 mol of H2\text{H}_2 reacts with excess O2\text{O}_2? (2H2+O2→2H2O2\text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O})

Example 6

medium
CH4+2O2→CO2+2H2O\text{CH}_4 + 2\text{O}_2 \rightarrow \text{CO}_2 + 2\text{H}_2\text{O}. Volume of CO2\text{CO}_2 at STP from 32 g of CH4_4? (MCH4=16M_{\text{CH}_4}=16)

Example 7

hard
How many grams of NH3\text{NH}_3 can be produced from 28.028.0 g of N2\text{N}_2 and excess H2\text{H}_2? (N2+3H2→2NH3\text{N}_2 + 3\text{H}_2 \rightarrow 2\text{NH}_3)

Example 8

challenge
In CH4+2O2→CO2+2H2OCH_4 + 2O_2 \rightarrow CO_2 + 2H_2O, how many grams of CO2CO_2 from 8 g CH4CH_4? (MCH4=16M_{CH_4}=16, MCO2=44M_{CO_2}=44)

Example 9

medium
For the reaction in X12, what is the maximum mass of H2O\text{H}_2\text{O} produced? (MH2O=18M_{\text{H}_2\text{O}}=18)

Example 10

challenge
In 2H2+O2→2H2O2H_2 + O_2 \rightarrow 2H_2O, how many molecules of H2OH_2O from 8 g H2H_2? (MH2=2M_{H_2}=2)

Example 11

medium
In C+O2→CO2C + O_2 \rightarrow CO_2, how many grams of CO2CO_2 from 6 g of C? (C=12, MCO2=44M_{CO_2}=44)

Example 12

easy
Is H2+O2→H2OH_2 + O_2 \rightarrow H_2O balanced?

Example 13

easy
In 2Na+Cl2→2NaCl2Na + Cl_2 \rightarrow 2NaCl, how many moles of NaClNaCl from 2 mol NaNa?

Example 14

easy
For 2H2+O2→2H2O2\text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O}, how many moles of H2\text{H}_2 are needed to make 5 mol5\,\text{mol} of H2O\text{H}_2\text{O}?

Example 15

hard
Percent yield: in N2+3H2→2NH3\text{N}_2 + 3\text{H}_2 \rightarrow 2\text{NH}_3, 28.0 g N228.0\,\text{g N}_2 with excess H2_2 yields 30.6 g NH330.6\,\text{g NH}_3. Find percent yield. (MN2=28.0M_{\text{N}_2}=28.0, MNH3=17.0M_{\text{NH}_3}=17.0)

Example 16

hard
2H2+O2→2H2O2\text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O}. Volume of O2\text{O}_2 at STP needed to react with 11.2 L H211.2\,\text{L H}_2 at STP?

Example 17

hard
H2SO4+2NaOH→Na2SO4+2H2O\text{H}_2\text{SO}_4 + 2\text{NaOH} \rightarrow \text{Na}_2\text{SO}_4 + 2\text{H}_2\text{O}. Volume of 0.500 M0.500\,\text{M} NaOH to neutralize 40.0 mL40.0\,\text{mL} of 0.200 M0.200\,\text{M} H2_2SO4_4?

Example 18

challenge
2Al+6HCl→2AlCl3+3H22\text{Al} + 6\text{HCl} \rightarrow 2\text{AlCl}_3 + 3\text{H}_2. A student combines 10.0 g Al10.0\,\text{g Al} with 100 mL100\,\text{mL} of 6.00 M HCl6.00\,\text{M HCl}. Find limiting reactant, mass AlCl3_3, and volume of H2_2 at STP. (MAl=27.0M_{\text{Al}}=27.0, MAlCl3=133.5M_{\text{AlCl}_3}=133.5)

Example 19

challenge
Burning 4 mol C2H6C_2H_6 in 2C2H6+7O2→4CO2+6H2O2C_2H_6 + 7O_2 \rightarrow 4CO_2 + 6H_2O needs how many mol O2O_2?

Example 20

easy
Balance: _ Fe+_ O2→_ Fe2O3\_\,\text{Fe} + \_\,\text{O}_2 \rightarrow \_\,\text{Fe}_2\text{O}_3.
← Back to Stoichiometry Worked Examples Formula Explained