This study guide covers various stoichiometry calculations students will need to know for an upcoming test, including: 1) Describing chemical reactions in terms of particles and moles. 2) Determining the mass and volume of products from a balanced chemical equation. 3) Showing conservation of mass through balanced equations. 4) Performing mole-to-mole conversions and stoichiometric calculations involving mass, moles, particles and volume. 5) Identifying limiting reagents and calculating theoretical and percent yields.

1. Name _______________________________________ Date ______________________
Chapter 12 – Stoichiometry
Study Guide
The following example problems exhibit the types of calculations you will be expected to
perform on tomorrow’s test.
• Describe a reaction in terms of particles
Ex.) Describe the following reaction in terms of molecules
6CO2 + 6H2O  C6H12O6 + 6O2
* Note: sometimes you will need to include other descriptors such as atoms and formula
units*
• Describe a reaction in terms of moles
Ex.) Describe the following reaction in terms of moles
2KCl  2K + Cl2
• How do you determine the mass of the products for a balanced reaction?
Ex.) What is the mass of the product formed in the following equation?
H2 + Cl2 2HCl
• How do you determine the volume of the reactants or products of a balanced
reaction?
Ex.) What is the volume of the products and the reactants of the following equation?
2H2 + O2  2H2O
• How do you show how a balanced reaction follows the Law of Conservation of Mass
by showing that the mass on both sides of a reaction are equal?
Ex.) Show how the mass of the reactants equals the mass of the products for the
following equation.

2. PCl5  PCl3 + Cl2
• How do you do mole to mole conversions?
Ex.) Given the reaction
PbCl2 + Na2CrO4  PbCrO4 + 2NaCl
What is the total number of moles of NaCl produced for every mole of PbCl2 that
reacts?
What is the total number of moles of NaCl produced if 2 moles of Na2CrO4 react
completely?
How many mole of NaCl are produced when 2.57 moles of PbCl2 react completely?
How many moles of PbCl2 are needed to produce 8.5 moles of PbCrO4?
• What are the steps to calculate Stoichiometric problems?
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2.
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4.
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• Mass to mass example problem
Ex.) Given the reaction

3. N2 + 3H2  2NH3
How many grams of NH3 are produced when 2.3 grams of N2 react?
How many grams of H2 are needed to produce 5.0 grams of NH3?
• Volume to volume example problem
Ex.) Given the reaction
2CO + O2  2 CO2
How man liters of CO are needed to completely react with 16.5 liters of O2?
• Miscellaneous stoichiometric problems
Ex.) Given the equation
Zn + 2HCl  ZnCl2 + H2
How many molecules of H2 are produced when 2.5 grams of Zn are reacted?
• What is the limiting reagent?
• How do you find the limiting reagent in a balanced equation?
Ex.) Given the reaction
Ca + 2H2O  Ca(OH)2 + H2
If 10.5 grams of Ca reacts with 5.2 grams of H2O, how many grams of the product
Ca(OH)2 will be formed?

4. Which reactant is the limiting factor?
• What is the actual yield?
• What is the theoretical yield?
Ex.) Given the equation
3Fe + 4H20  Fe3O4 + 4H2
How much Fe3O4 should be produced when 11.2 grams of Fe react with an excess of
water?
• How do you calculate the percent yield?
Ex.) Given the equation
3Fe + 4H20  Fe3O4 + 4H2
Use your answer from the example above as the theoretical yield.
If the actual yield for this reaction was 15 grams of Fe3O4, what is the percent yield of
Fe3O4 for this reaction?