STOICHIOMETRY REVIEW
Directions: Complete the following problems. All work must be shown in order to receive credit!
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A balanced chemical equation allows one to determine the
a. Mole ratio of any two substances in the reaction
b. Energy release in the reaction
c. Electron configuration of all elements in the reaction
d. Mechanism involved in the reaction
The coefficients in a chemical equation represent the
a. Masses, in grams, of all reactants and products
b. Relative numbers of moles of reactants and products
c. Number of atoms in each compound in a reaction
d. Number of valence electrons involved in the reaction
If one knows the mole ratio of a reactant and product in a chemical reactions, one can
a. Estimate the energy released in the reaction
b. Calculate the speed of the reaction
c. Calculate the mass of the product produces from a know mass of reactant
d. Decide whether the reaction is reversible
In the reaction N2 + 3H2  2NH3, what is the mole ratio of nitrogen to ammonia
a. 1:1
b. 1:2
c. 1:3
d. 2:3
The Haber process for producing ammonia commercially is represented by the equation
N2(g) + 3H2(g) 2NH3 (g). To completely convert 9.0 moles hydrogen gas to ammonia gas, how
many moles of nitrogen gas are required?
a. 1.0 moles
b. 2.0 moles
c. 3.0 moles
d. 6.0 moles
For the equation 2KClO3  2KCl + 3O2, how many moles of oxygen are produced when 3.0
moles of KClO3 decompose completely?
a. 1.0 moles
b. 2.5 moles
c. 3.0 moles
d. 4.5 moles
For the reaction 2H2 + O2  2H2O, how many moles of water can be produced from 6.0 moles of
oxygen?
a. 2.0 moles
b. 6.0 moles
c. 12 moles
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d. 18 moles
For the reaction N2 + 3H2  2NH3, how many moles of nitrogen are required to produce 18
moles of ammonia?
a. 9.0 moles
b. 18 moles
c. 27 moles
d. 36 moles
For the reaction Cl2 + 2KBr  2KCl + Br2, how many grams of potassium chloride can be
produced from 300 grams each of chlorine and potassium bromide? (hint: find theoretical yield)
a. 98.7 grams
b. 111 grams
c. 188 grams
d. 451 grams
For the reaction 2Na + Cl2  2NaCl, how many grams of sodium chloride can be produced from
500 grams each of sodium and chlorine?
a. 112 grams
b. 319 grams
c. 409 grams
d. 825 grams
For the reaction SO3 + H2O  H2SO4 calculate the percent yield if 500 grams of sulfur trioxide
react with excess water to produce 575 grams of sulfuric acid.
a. 82.7%
b. 88.3%
c. 91.2%
d. 93.9%
For the reaction Mg + 2HCl  H2 + MgCl2, calculate the percent yield of magnesium chloride if
100 grams of magnesium react with excess hydrochloric acid to yield 330 grams of magnesium
chloride.
a. 71.8%
b. 74.3%
c. 81.6%
d. 84.2%
Which reactant controls the amount of product formed in a chemical reaction?
a. Excess reactant
b. Mole ratio
c. Composition reaction
d. Limiting reactant
In the reaction A + B  C + D, if the quantity of B is insufficient to react with all of A,
a. A is the limiting reactant
b. B is the limiting reactant
c. There is no limiting reactant
d. No product can be formed
15. What is the ratio of the actual yield to the theoretical yield, multiplied by 100%
a. Mole ratio
b. Percent yield
c. Avogadro yield
d. Excess yield
16. A chemist interested in the efficiency of a chemical reaction would calculate the
a. Mole ratio
b. Energy released
c. Percent yield
d. Rate of reaction
17. Identify the limiting reactant when 10.0 grams H2O reacts with 4.5 grams Na to produce NaOH
and H2.
2H2O + Na  2NaOH + H2
18. When octane (C8H18) is burned in oxygen, carbon dioxide and water is produced. If 320 grams of
octane is burned and 392 grams of water is recovered, what is the percent yield of the
experiment?
2C8H18 + 25O2  16CO2 + 18H2O
19. When 9.00 grams of Al react with excess H3PO4, 30.0 grams of AlPO4 are produced. What is the
percent yield of this reaction?
2Al(s) + 2 H3PO4  2 AlPO4 (aq) + 3H2(g)