Multiple Choice
Identify the
choice that best completes the statement or answers the question.
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1.
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Which branch of chemistry deals with the mass relationships of elements in
compounds and the mass relationships among reactants and products in chemical reactions?
a. | qualitative analysis | c. | chemical kinetics | b. | entropy | d. | stoichiometry |
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2.
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What is the study of the mass relationships of elements in compounds?
a. | reaction stoichiometry | c. | percentage yield | b. | composition stoichiometry | d. | Avogadro's
principle |
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3.
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What is the study of the mass relationships among reactants and products in a
chemical reaction?
a. | reaction stoichiometry | c. | electron configuration | b. | composition
stoichiometry | d. | periodic
law |
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4.
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Which of the following would be investigated in reaction stoichiometry?
a. | the masses of hydrogen and oxygen in water | b. | the amount of energy
released in chemical reactions | c. | the mass of potassium required to produce a
known mass of potassium chloride | d. | the types of bonds that break and form when
acids react with metals |
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5.
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A determination of the masses and number of moles of sulfur and oxygen in the
compound sulfur dioxide would be studied in
a. | reaction stoichiometry. | c. | chemical
equilibrium. | b. | chemical kinetics. | d. | composition stoichiometry. |
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6.
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Which of the following would not be studied in the branch of chemistry
called stoichiometry?
a. | the mole ratio of aluminum and chlorine in aluminum chloride | b. | the amount of energy
required to break the ionic bonds in calcium fluoride | c. | the mass of carbon produced when a known mass
of sucrose decomposes | d. | the number of moles of hydrogen that reacts
completely with a known quantity of oxygen |
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7.
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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. |
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8.
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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 released in
the reaction. | c. | electron configuration of all elements in the reaction. | d. | mechanism involved
in the reaction. |
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9.
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To balance a chemical equation, it may be necessary to adjust the
a. | coefficients. | c. | formulas of the products. | b. | subscripts. | d. | number of products. |
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10.
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A chemical equation is balanced when the
a. | coefficients of the reactants equal the coefficients of the
products. | b. | same number of each kind of atom appears in the reactants and in the
products. | c. | products and reactants are the same chemicals. | d. | subscripts of the
reactants equal the subscripts of the products. |
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11.
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If one knows the mole ratio of a reactant and product in a chemical reaction,
one can
a. | estimate the energy released in the reaction. | b. | calculate the speed
of the reaction. | c. | calculate the mass of the product produced from a known mass of
reactant. | d. | decide whether the reaction is reversible. |
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12.
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Given the equation  , the starting mass of A, and its molar mass, and
you are asked to determine the moles of C produced, your first step in solving the problem is the
multiply the given mass of A by
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13.
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In the chemical reaction represented by the equation wA + xB ® yC + zD, a comparison of the number of moles of A to the number of moles
of C would be a(n)
a. | mass ratio. | c. | electron ratio. | b. | mole ratio. | d. | energy
proportion. |
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14.
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In what kind of reaction do two or more substances combine to form a new
compound?
a. | decomposition reaction | c. | double-displacement reaction | b. | combustion
reaction | d. | synthesis
reaction |
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15.
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The units of molar mass are
a. | g/mol. | c. | amu/mol. | b. | mol/g. | d. | amu/g. |
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16.
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In the reaction represented by the equation N2 + 3H2 ® 2NH3, what is the mole ratio of nitrogen to ammonia?
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17.
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In the reaction represented by the equation C + 2H2 ® CH4, what is the mole ratio of hydrogen to methane?
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18.
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The Haber process for producing ammonia commercially is represented by the
equation N2(g) + 3H2(g) ®
2NH3(g). To completely convert 9.0 mol hydrogen gas to ammonia gas, how many moles
of nitrogen gas are required?
a. | 1.0 mol | c. | 3.0 mol | b. | 2.0 mol | d. | 6.0 mol |
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19.
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In the equation 2KClO3 ® 2KCl +
3O2, how many moles of oxygen are produced when 3.0 mol of KClO3 decompose
completely?
a. | 1.0 mol | c. | 3.0 mol | b. | 2.5 mol | d. | 4.5 mol |
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20.
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For the reaction represented by the equation C + 2H2 ® CH4, how many moles of hydrogen are required to produce 10 mol
of methane, CH4?
a. | 2 mol | c. | 10 mol | b. | 4 mol | d. | 20 mol |
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21.
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For the reaction represented by the equation 2H2 + O2® 2H2O, how many moles of water can be produced from 6.0 mol of
oxygen?
a. | 2.0 mol | c. | 12 mol | b. | 6.0 mol | d. | 18 mol |
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22.
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For the reaction represented by the equation N2 + 3H2
® 2NH3, how many moles of nitrogen are required to produce
18 mol of ammonia?
a. | 9.0 mol | c. | 27 mol | b. | 18 mol | d. | 36 mol |
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23.
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For the reaction represented by the equation AgNO3 + NaCl ® NaNO3 + AgCl, how many moles of silver chloride, AgCl, are
produced from 7.0 mol of silver nitrate AgNO3?
a. | 1.0 mol | c. | 7.0 mol | b. | 2.3 mol | d. | 21 mol |
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Use the table below to answer the following questions.
| Element | Symbol | Atomic
Mass | | Bromine | Br | 79.90 | | Calcium | Ca | 40.08 | | Carbon | C | 12.01 | | Chlorine | Cl | 35.45 | | Cobalt | Co | 58.93 | | Copper | Cu | 63.55 | | Fluorine | F | 19.00 | | Hydrogen | H | 1.01 | | Iodine | I | 126.90 | | Iron | Fe | 55.85 | | Lead | Pb | 207.2 | | Magnesium | Mg | 24.30 | | Mercury | Hg | 200.59 | | Nitrogen | N | 14.01 | | Oxygen | O | 15.00 | | Potassium | K | 39.10 | | Sodium | Na | 22.99 | | Sulfur | S | 32.01 | | | |
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24.
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For the reaction represented by the equation 2H2 + O2
® 2H2O, how many grams of water are produced from 6.00 mol
of hydrogen?
a. | 2.00 g | c. | 54.0 g | b. | 6.00 g | d. | 108 g |
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25.
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For the reaction represented by the equation SO3 + H2O
® H2SO4, how many grams of sulfur trioxide are
required to produce 4.00 mol of sulfuric acid in an excess of water?
a. | 80.0 g | c. | 240. g | b. | 160. g | d. | 320. g |
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26.
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For the reaction represented by the equation 2Fe + O2 ® 2FeO, how many grams of iron(II) oxide are produced from 8.00 mol of iron
in an excess of oxygen?
a. | 71.8 g | c. | 712 g | b. | 575 g | d. | 1310 g |
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27.
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For the reaction represented by the equation 2Na + Cl2 ® 2NaCl, how many grams of chlorine gas are required to react completely
with 2.00 mol of sodium?
a. | 35.5 g | c. | 141.8 g | b. | 70.9 g | d. | 212.7 g |
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28.
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For the reaction represented by the equation 2HNO3 +
Mg(OH)2 ® Mg(NO3)2 +
2H2O, how many grams of magnesium nitrate are produced from 8.00 mol of nitric acid,
HNO3, and an excess of Mg(OH)2?
a. | 148 g | c. | 593 g | b. | 445 g | d. | 818 g |
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29.
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For the reaction represented by the equation CH4 + 2O2
® CO2 + 2H2O, how many moles of carbon dioxide
are produced from the combustion of 100. g of methane?
a. | 6.23 mol | c. | 12.5 mol | b. | 10.8 mol | d. | 25 mol |
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30.
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For the reaction represented by the equation Pb(NO3)2 +
2KI ® PbI2 + 2KNO3, how many moles of lead(II)
iodide are produced from 300. g of potassium iodide and an excess of
Pb(NO3)2?
a. | 0.904 mol | c. | 3.61 mol | b. | 1.81 mol | d. | 11.0 mol |
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31.
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For the reaction represented by the equation 3Fe + 4H2O ® Fe3O4 + 4H2, how many moles of iron(III)
oxide are produced from 500. g of iron in an excess of H2O?
a. | 1.04 mol | c. | 8.95 mol | b. | 2.98 mol | d. | 12.98 mol |
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32.
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For the reaction represented by the equation 2KlO3 ® 2KCl + 3O2, how many moles of potassium chlorate are required
to produce 250. g of oxygen?
a. | 2.00 mol | c. | 4.97 mol | b. | 4.32 mol | d. | 5.21 mol |
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33.
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Ozone, O 3, is produced by the reaction represented by the following
equation:  What mass of ozone will form from the
reaction of 2.0 g of NO 2 in a car's exhaust and excess oxygen? a. | 1.1 g O3 | c. | 2.1 g O3 | b. | 1.8 g O3 | d. | 4.2 g
O3 |
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34.
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For the reaction represented by the equation Cl2 + 2KBr ® 2KCl + Br2, how many grams of potassium chloride can be
produced from 300. g each of chlorine and potassium bromide?
a. | 98.7 g | c. | 188 g | b. | 111 g | d. | 451 g |
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35.
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For the reaction represented by the equation 2Na + 2H2O ® 2NaOH + H2, how many grams of hydrogen are produced if 120. g
of sodium and 80. g of water are available?
a. | 4.5 g | c. | 80. g | b. | 45 g | d. | 200 g |
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36.
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For the reaction represented by the equation 2Na + Cl2 ® 2NaCl, how many grams of sodium chloride can be produced from 500. g each
of sodium and chlorine?
a. | 112 g | c. | 409 g | b. | 319 g | d. | 824 g |
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37.
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For the reaction represented by the equation SO3 + H2O
® H2SO4, how many grams of sulfuric acid can be
produced from 200. g of sulfur trioxide and 100. g of water?
a. | 100. g | c. | 245 g | b. | 200. g | d. | 285 g |
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38.
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Which reactant controls the amount of product formed in a chemical
reaction?
a. | excess reactant | c. | composition reactant | b. | mole ratio | d. | limiting
reactant |
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39.
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A chemical reaction involving substances A and B stops when B is completely
used. B is the
a. | excess reactant. | c. | primary reactant. | b. | limiting reactant. | d. | primary
product. |
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40.
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When the limiting reactant in a chemical reaction is completely used, the
a. | excess reactants begin combining. | c. | reaction speeds
up. | b. | reaction slows down. | d. | reaction stops. |
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41.
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To determine the limiting reactant in a chemical reaction involving known masses
of A and B, one could first calculate
a. | the mass of 100 mol of A and B. | b. | the masses of all products. | c. | the bond energies of
A and B. | d. | the number of moles of B and the number of moles of A
available. |
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42.
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After calculating the amount of reactant B required to completely react with A,
then comparing that amount with the amount of B available, one can determine the
a. | limiting reactant. | c. | energy released in the reaction. | b. | rate of the
reaction. | d. | pathway of the
reaction. |
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43.
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What is the measured amount of a product obtained from a chemical
reaction?
a. | mole ratio | c. | theoretical yield | b. | percentage yield | d. | actual yield |
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44.
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What is the maximum possible amount of product obtained in a chemical
reaction?
a. | theoretical yield | c. | mole ratio | b. | percentage yield | d. | actual yield |
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45.
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A chemist interested in the efficiency of a chemical reaction would calculate
the
a. | mole ratio. | c. | percentage yield. | b. | energy released. | d. | rate of
reaction. |
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46.
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If the percentage yield is equal to 100%, then
a. | the actual yield is greater than the theoretical yield. | b. | the actual yield is
equal to the theoretical yield. | c. | the actual yield is less than the theoretical
yield. | d. | there was no limiting reactant. |
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47.
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For the reaction represented by the equation SO3 + H2O
® H2SO4, calculate the percentage yield if 500.
g of sulfur trioxide react with excess water to produce 575 g of sulfuric acid.
a. | 82.7% | c. | 91.2% | b. | 88.3% | d. | 93.9% |
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48.
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For the reaction represented by the equation Cl2 + 2KBr ® 2KCl + Br2, calculate the percentage yield if 200. g of
chlorine react with excess potassium bromide to produce 410. g of bromine.
a. | 73.4% | c. | 91.0% | b. | 82.1% | d. | 98.9% |
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49.
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For the reaction represented by the equation CH4 + 2O2
® 2H2O + CO2, calculate the percentage yield of
carbon dioxide if 1000. g of methane react with excess oxygen to produce 2300. g of carbon
dioxide.
a. | 83.88% | c. | 92.76% | b. | 89.14% | d. | 96.78% |
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50.
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For the reaction represented by the equation Mg + 2HCl ® H2 + MgCl2, calculate the percentage yield of
magnesium chloride if 100. g of magnesium react with excess hydrochloric acid to yield 330. g of
magnesium chloride.
a. | 71.8% | c. | 81.6% | b. | 74.3% | d. | 84.2% |
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