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

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

2\text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O}

. Molar mass H

_2

= 2 g/mol. Mass of

\text{H}_2

needed to react with 16 g O

_2

? (

M_{\text{O}_2}=32

)

Example 2

easy

\text{N}_2 + 3\text{H}_2 \rightarrow 2\text{NH}_3

. Moles NH

_3

from 0.5 mol N

_2

(excess H

_2

Example 3

hard

\text{HCl} + \text{NaOH} \rightarrow \text{NaCl} + \text{H}_2\text{O}

. Volume of

0.250\,\text{M}

NaOH needed to neutralize

25.0\,\text{mL}

0.100\,\text{M}

HCl?

Example 4

medium

\text{Fe}_2\text{O}_3 + 3\text{CO} \rightarrow 2\text{Fe} + 3\text{CO}_2

. Mass Fe from

159.7\,\text{g Fe}_2\text{O}_3

? (

M=159.7

M_{\text{Fe}}=55.85

)

Example 5

medium

How many moles of

\text{H}_2\text{O}

are produced when

3.0

mol of

\text{H}_2

reacts with excess

\text{O}_2

? (

2\text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O}

)

Example 6

medium

\text{CH}_4 + 2\text{O}_2 \rightarrow \text{CO}_2 + 2\text{H}_2\text{O}

. Volume of

\text{CO}_2

at STP from 32 g of CH

_4

? (

M_{\text{CH}_4}=16

)

Example 7

hard

How many grams of

\text{NH}_3

can be produced from

28.0

g of

\text{N}_2

and excess

\text{H}_2

? (

\text{N}_2 + 3\text{H}_2 \rightarrow 2\text{NH}_3

)

Example 8

challenge

CH_4 + 2O_2 \rightarrow CO_2 + 2H_2O

, how many grams of

CO_2

from 8 g

CH_4

? (

M_{CH_4}=16

M_{CO_2}=44

)

Example 9

medium

For the reaction in X12, what is the maximum mass of

\text{H}_2\text{O}

produced? (

M_{\text{H}_2\text{O}}=18

)

Example 10

challenge

2H_2 + O_2 \rightarrow 2H_2O

, how many molecules of

H_2O

from 8 g

H_2

? (

M_{H_2}=2

)

Example 11

medium

C + O_2 \rightarrow CO_2

, how many grams of

CO_2

from 6 g of C? (C=12,

M_{CO_2}=44

)

Example 12

easy

H_2 + O_2 \rightarrow H_2O

balanced?

Example 13

easy

2Na + Cl_2 \rightarrow 2NaCl

, how many moles of

NaCl

from 2 mol

Na

Example 14

easy

For

2\text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O}

, how many moles of

\text{H}_2

are needed to make

5\,\text{mol}

\text{H}_2\text{O}

Example 15

hard

Percent yield: in

\text{N}_2 + 3\text{H}_2 \rightarrow 2\text{NH}_3

28.0\,\text{g N}_2

with excess H

_2

yields

30.6\,\text{g NH}_3

. Find percent yield. (

M_{\text{N}_2}=28.0

M_{\text{NH}_3}=17.0

)

Example 16

hard

2\text{H}_2 + \text{O}_2 \rightarrow 2\text{H}_2\text{O}

. Volume of

\text{O}_2

at STP needed to react with

11.2\,\text{L H}_2

at STP?

Example 17

hard

\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\,\text{M}

NaOH to neutralize

40.0\,\text{mL}

0.200\,\text{M}

_2

_4

Example 18

challenge

2\text{Al} + 6\text{HCl} \rightarrow 2\text{AlCl}_3 + 3\text{H}_2

. A student combines

10.0\,\text{g Al}

with

100\,\text{mL}

6.00\,\text{M HCl}

. Find limiting reactant, mass AlCl

_3

, and volume of H

_2

at STP. (

M_{\text{Al}}=27.0

M_{\text{AlCl}_3}=133.5

)

Example 19

challenge

Burning 4 mol

C_2H_6

2C_2H_6 + 7O_2 \rightarrow 4CO_2 + 6H_2O

needs how many mol

O_2

Example 20

easy

Balance:

\_\,\text{Fe} + \_\,\text{O}_2 \rightarrow \_\,\text{Fe}_2\text{O}_3

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Related Concepts

Mole Balancing Equations Molar Mass Limiting Reactant Theoretical Yield Percent Yield