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General Chemistry: Atoms First
Chapter 6 Chemical Arithmetic: Stoichiometry
6.1 Multiple Choice Questions
1) Which one of the following statements about balanced equations is false? In a balanced reaction
A) atoms must be balanced on both sides of the reaction arrow.
B) mass must be conserved.
C) molecules must be balanced on both sides of the reaction arrow.
D) net charge must be balanced on both sides of the reaction arrow.
Answer: C
Diff: 1
Topic: Section 6.2 Balancing Chemical Equations
2) Which one of the following statements about balanced equations is true? A reaction is balanced by
A) changing the charge on an ion.
B) changing the formula of the molecule.
C) multiplying by suitable coefficients.
D) rearranging atoms in a molecule.
Answer: C
Diff: 1
Topic: Section 6.2 Balancing Chemical Equations
3) What is the stoichiometric coefficient for oxygen when the following equation is balanced using the lowest, whole-number coefficients
___ C3H8O(l) + ___ O2(g) → ___ CO2(g) + ___ H2O(l)
A) 3
B) 5
C) 7
D) 9
Answer: D
Diff: 2
Topic: Section 6.2 Balancing Chemical Equations
Algo. Option: algorithmic
4) What is the sum of the coefficients when the following equation is balanced using the lowest, whole numbered coefficients?
___ PH3(g) + ___ O2(g) → ___ P4O10(s) + ___ H2O(g)
A) 10
B) 12
C) 19
D) 22
Answer: C
Diff: 2
Topic: Section 6.2 Balancing Chemical Equations
5) What is the sum of the coefficients when the following equation is balanced using the lowest, whole numbered coefficients?
___ B2O3(s) + ___ HF(l) → ___ BF3(g) + ___ H2O(l)
A) 8
B) 11
C) 15
D) none of these
Answer: D
Diff: 2
Topic: Section 6.2 Balancing Chemical Equations
6) Aluminum metal reacts with iron(II) sulfide to form aluminum sulfide and iron metal. What is the stoichiometric coefficient for aluminum when the chemical equation is balanced using the lowest, whole-number stoichiometric coefficients?
A) 1
B) 2
C) 3
D) 4
Answer: B
Diff: 3
Topic: Section 6.2 Balancing Chemical Equations
Algo. Option: algorithmic
7) Calcium phosphate reacts with sulfuric acid to form calcium sulfate and phosphoric acid. What is the stoichiometric coefficient for sulfuric acid when the chemical equation is balanced using the lowest, whole-number stoichiometric coefficients?
A) 1
B) 2
C) 3
D) none of these
Answer: C
Diff: 3
Topic: Section 6.1 Chemical Symbols on Different Levels
Algo. Option: algorithmic
8) Given the chemical equation: N2 + 3 H2 → 2 NH3. On a microscopic level, what do the coefficients mean?
A) 1 atom of nitrogen reacts with 3 atoms of hydrogen to give 2 atoms of ammonia.
B) 28 g of nitrogen reacts with 6 grams of hydrogen to give 34 grams of ammonia.
C) 1 mole of nitrogen reacts with 3 moles of hydrogen to give 2 moles of ammonia.
D) 1 molecule of nitrogen reacts with 3 molecules of hydrogen to give 2 molecules of ammonia.
Answer: D
Diff: 1
Topic: Section 6.1 Chemical Symbols on Different Levels
9) Given the chemical equation: N2 + 3 H2 → 2 NH3. On a macroscopic level, what do the coefficients mean?
A) 1 atom of nitrogen reacts with 3 atoms of hydrogen to give 2 atoms of ammonia.
B) 1 mole of nitrogen reacts with 3 moles of hydrogen to give 2 moles of ammonia.
C) 1 molecule of nitrogen reacts with 3 molecules of hydrogen to give 2 molecules of ammonia.
D) all of the above
Answer: B
Diff: 1
Topic: Section 6.1 Chemical Symbols on Different Levels
10) 1.00 mole of O2 contains the same number of molecules as
A) 0.667 mole of O3.
B) 1.00 mole of CH3CO2H.
C) 2.00 mole of CH3CH2OH.
D) all of the above.
Answer: B
Diff: 1
Topic: Section 6.3 Stoichiometry: The Arithmetic of Chemical Reactions
11) 1.00 mole of O2 contains the same number of oxygen atoms as
A) 0.667 mole of O3.
B) 1.00 mole of CH3CO2H.
C) 2.00 mole of CH3CH2OH.
D) all of the above.
Answer: D
Diff: 2
Topic: Section 6.3 Stoichiometry: The Arithmetic of Chemical Reactions
12) What is the mass of an atom of the element hydrogen?
A) 2.0 g
B) 1.0 g
C) 3.4 × 10–24 g
D) 1.7 × 10–24 g
Answer: D
Diff: 2
Topic: Section 6.3 Stoichiometry: The Arithmetic of Chemical Reactions
13) What is the molar mass of aspartic acid, C4O4H7N?
A) 43 g/mol
B) 70 g/mol
C) 133 g/mol
D) 197 g/mol
Answer: C
Diff: 2
Topic: Section 6.2 Balancing Chemical Equations
14) What is the molar mass of Co(NO3)2?
A) 90 g/mol
B) 121 g/mol
C) 152 g/mol
D) 183 g/mol
Answer: D
Diff: 2
Topic: Section 6.2 Balancing Chemical Equations
15) What is the molar mass of calcium permanganate?
A) 159 g/mol
B) 199 g/mol
C) 216 g/mol
D) 278 g/mol
Answer: D
Diff: 3
Topic: Section 6.2 Balancing Chemical Equations
16) What is the molar mass of hydrogen gas?
A) 1.00 g/mol
B) 2.00 g/mol
C) 6.02 × 1023 g/mol
D) 1.20 × 1023 g/mol
Answer: B
Diff: 2
Topic: Section 6.2 Balancing Chemical Equations
Algo. Option: algorithmic
17) What is the mass of a single chlorine molecule, Cl2?
A) 5.887 × 10-23 g
B) 1.177 × 10-22 g
C) 35.45 g
D) 70.90 g
Answer: B
Diff: 2
Topic: Section 6.3 Stoichiometry: The Arithmetic of Chemical Reactions
Algo. Option: algorithmic
18) What is the mass of 0.500 mol of dichlorodifluoromethane, CF2Cl2?
A) 4.14 × 10-3 g
B) 60.5 g
C) 121 g
D) 242 g
Answer: B
Diff: 2
Topic: Section 6.3 Stoichiometry: The Arithmetic of Chemical Reactions
Algo. Option: algorithmic
19) How many moles are in 1.50 g of ethanol, CH3CH2OH?
A) 0.0145 mol
B) 0.0326 mol
C) 30.7 mol
D) 69.0 mol
Answer: B
Diff: 2
Topic: Section 6.3 Stoichiometry: The Arithmetic of Chemical Reactions
Algo. Option: algorithmic
20) How many iron(II) ions, Fe2+ are there in 5.00 g of FeSO4?
A) 5.46 × 10-26 iron (II) ions
B) 1.98 × 1022 iron (II) ions
C) 1.83 × 1025 iron (II) ions
D) 4.58 × 1026 iron (II) ions
Answer: B
Diff: 3
Topic: Section 6.3 Stoichiometry: The Arithmetic of Chemical Reactions
Algo. Option: algorithmic
21) What is the mass of 8.50 × 1022 molecules of NH3?
A) 0.00830 g
B) 0.417 g
C) 2.40 g
D) 120 g
Answer: C
Diff: 3
Topic: Section 6.3 Stoichiometry: The Arithmetic of Chemical Reactions
Algo. Option: algorithmic
22) How many oxygen atoms are in 3.00 g of sodium dichromate, Na2Cr2O7?
A) 0.0801 oxygen atoms
B) 9.85 × 1020 oxygen atoms
C) 6.90 × 1021 oxygen atoms
D) 4.83 × 1022 oxygen atoms
Answer: D
Diff: 3
Topic: Section 6.3 Stoichiometry: The Arithmetic of Chemical Reactions
Algo. Option: algorithmic
23) What is the identity of substance X if 0.380 mol of X weighs 17.5 g?
A) NO2
B) NO3
C) N2O
D) N2O4
Answer: A
Diff: 3
Topic: Section 6.3 Stoichiometry: The Arithmetic of Chemical Reactions
24) What is the molar mass of butane if 5.19 × 1016 molecules of butane weigh 5.00 μg?
A) 58.0 g/mol
B) 172 g/mol
C) 232 g/mol
D) 431 g/mol
Answer: A
Diff: 3
Topic: Section 6.3 Stoichiometry: The Arithmetic of Chemical Reactions
Algo. Option: algorithmic
25) What mass of dinitrogen monoxide, N2O, contains the same number of molecules as 3.00 g of trichlorofluoromethane, CCl3F?
A) 0.106 g
B) 0.961 g
C) 1.04 g
D) 9.37 g
Answer: B
Diff: 3
Topic: Section 6.3 Stoichiometry: The Arithmetic of Chemical Reactions
Algo. Option: algorithmic
26) What mass of sulfur hexafluoride, SF6, has the same number of fluorine atoms as 25.0 g of oxygen difluoride, OF2?
A) 0.901 g
B) 8.33 g
C) 22.5 g
D) 203 g
Answer: C
Diff: 4
Topic: Section 6.3 Stoichiometry: The Arithmetic of Chemical Reactions
Algo. Option: algorithmic
27) How many chloride ions are in 1.50 mol of aluminum chloride?
A) 3.00 chloride ions
B) 4.50 chloride ions
C) 9.03 × 1023 chloride ions
D) 2.71 × 1024 chloride ions
Answer: D
Diff: 3
Topic: Section 6.3 Stoichiometry: The Arithmetic of Chemical Reactions
Algo. Option: algorithmic
28) How many anions are in 0.500 g of MgBr2?
A) 1.64 × 1021 anions
B) 3.27 × 1021 anions
C) 2.22 × 1026 anions
D) 4.43 × 1026 anions
Answer: B
Diff: 3
Topic: Section 6.3 Stoichiometry: The Arithmetic of Chemical Reactions
Algo. Option: algorithmic
29) How many cations are in 10.0 g of sodium phosphate?
A) 3.67 × 1022 cations
B) 1.10 × 1023 cations
C) 9.87 × 1024 cations
D) 2.96 × 1025 cations
Answer: B
Diff: 3
Topic: Section 6.3 Stoichiometry: The Arithmetic of Chemical Reactions
Algo. Option: algorithmic
30) Which of the following has the greatest mass?
A) 6.0 × 1023 atoms of O
B) 3.0 × 1023 molecules of O2
C) 2.0 × 1023 molecules of O3
D) All have the same mass.
Answer: D
Diff: 3
Topic: Section 6.3 Stoichiometry: The Arithmetic of Chemical Reactions
31) Which of the following has the greatest mass?
A) 6.02 × 1023 molecules of O2
B) 16.0 g of O2
C) 0.500 mol of O2
D) All of the above have the same mass.
Answer: A
Diff: 3
Topic: Section 6.3 Stoichiometry: The Arithmetic of Chemical Reactions
Algo. Option: algorithmic
32) Which of the following has the smallest mass?
A) 3.50 × 1023 molecules of I2
B) 85.0 g of Cl2
C) 2.50 mol of F2
D) 0.050 kg of Br2
Answer: D
Diff: 3
Topic: Section 6.3 Stoichiometry: The Arithmetic of Chemical Reactions
Algo. Option: algorithmic
33) How many moles of CuO can be produced from 0.450 mol of Cu2O in the following reaction?
2 Cu2O(s) + O2(g) → 4 CuO(s)
A) 0.225 mol
B) 0.450 mol
C) 0.900 mol
D) 1.80 mol
Answer: C
Diff: 3
Topic: Section 6.3 Stoichiometry: The Arithmetic of Chemical Reactions
Algo. Option: algorithmic
34) How many moles of BCl3 are needed to produce 25.0 g of HCl(aq) in the following reaction?
BCl3(g) + 3 H2O(l) → 3 HCl(aq) + B(OH)3(aq)
A) 0.229 mol
B) 0.686 mol
C) 2.06 mol
D) 4.38 mol
Answer: A
Diff: 3
Topic: Section 6.3 Stoichiometry: The Arithmetic of Chemical Reactions
Algo. Option: algorithmic
35) How many grams of calcium chloride are needed to produce 10.0 g of potassium chloride?
CaCl2(aq) + K2CO3(aq) → 2 KCl(aq) + CaCO3(aq)
A) 0.134 g
B) 7.44 g
C) 14.9 g
D) 29.8 g
Answer: B
Diff: 3
Topic: Section 6.3 Stoichiometry: The Arithmetic of Chemical Reactions
Algo. Option: algorithmic
36) Balance the chemical equation given below, and determine the number of moles of iodine that reacts with 10.0 g of aluminum.
___ Al(s) + ___ I2(s) → ___ Al2I6(s)
A) 0.247 mol
B) 0.556 mol
C) 0.741 mol
D) 1.11 mol
Answer: B
Diff: 4
Topic: Section 6.3 Stoichiometry: The Arithmetic of Chemical Reactions
Algo. Option: algorithmic
37) Balance the chemical equation given below, and determine the number of grams of MgO needed to produce 15.0 g of Fe2O3.
___ MgO(s) + ___ Fe(s) → ___ Fe2O3(s) + ___ Mg(s)
A) 0.0877 g
B) 1.26 g
C) 3.78 g
D) 11.4 g
Answer: D
Diff: 4
Topic: Section 6.3 Stoichiometry: The Arithmetic of Chemical Reactions
Algo. Option: algorithmic
38) Dinitrogen monoxide gas decomposes to form nitrogen gas and oxygen gas. How many grams of oxygen are formed when 5.00 g of dinitrogen monoxide decomposes?
A) 0.550 g
B) 1.82 g
C) 3.64 g
D) 7.27 g
Answer: B
Diff: 4
Topic: Section 6.3 Stoichiometry: The Arithmetic of Chemical Reactions
Algo. Option: algorithmic
39) The density of ethanol, C2H5OH, is 0.789 g/mL. How many milliliters of ethanol are needed to produce 10.0 g of CO2 according to the following chemical equation?
C2H5OH(l) + 3 O2(g) → 2 CO2(g) + 3 H2O(l)
A) 4.12 mL
B) 6.63 mL
C) 13.2 mL
D) 26.5 mL
Answer: B
Diff: 4
Topic: Section 6.3 Stoichiometry: The Arithmetic of Chemical Reactions
Algo. Option: algorithmic
40) When 10.0 g of calcium metal is reacted with water, 5.00 g of calcium hydroxide is produced. Using the following balanced equation, calculate the percent yield for the reaction?
Ca(s) + 2 H2O(l) → Ca(OH)2(aq) + H2(g)
A) 13.5%
B) 27.1%
C) 50.0%
D) 92.4%
Answer: B
Diff: 3
Topic: Section 6.4 Yields of Chemical Reactions
Algo. Option: algorithmic
41) If the percent yield for the following reaction is 65.0%, how many grams of KClO3 are needed to produce 42.0 g of O2?
2 KClO3(s) → 2 KCl(s) + 3 O2(g)
A) 69.7 g
B) 107 g
C) 165 g
D) 371 g
Answer: C
Diff: 3
Topic: Section 6.4 Yields of Chemical Reactions
Algo. Option: algorithmic
42) If the percent yield for the following reaction is 75.0%, and 45.0 g of NO2 are consumed in the reaction, how many grams of nitric acid, HNO3(aq), are produced?
3 NO2(g) + H2O(l) → 2 HNO3(aq) + NO(g)
A) 30.8 g
B) 41.1 g
C) 54.8 g
D) 69.3 g
Answer: A
Diff: 3
Topic: Section 6.4 Yields of Chemical Reactions
Algo. Option: algorithmic
43) In the reaction between glucose and oxygen, 10.0 g of glucose reacts and 7.50 L of carbon dioxide is formed. What is the percent yield if the density of CO2 is 1.26 g/L?
C6H12O6(s) + 6 O2(g) → 6 CO2(g) + 6 H2O(l)
A) 26.1%
B) 40.6%
C) 43.1%
D) 64.5%
Answer: D
Diff: 4
Topic: Section 6.4 Yields of Chemical Reactions
44) When methane, CH4, undergoes combustion with oxygen, the usual products are carbon dioxide and water. Carbon monoxide is formed when the limiting reactant is
A) carbon dioxide.
B) methane.
C) oxygen.
D) water.
Answer: C
Diff: 2
Topic: Section 6.5 Reactions with Limiting Amounts of Reactants
45) 10 g of nitrogen is reacted with 5.0 g of hydrogen to produce ammonia according to the chemical equation shown below. Which one of the following statements is false?
N2(g) + 3 H2(g) → 2 NH3(g)
A) 2.8 grams of hydrogen are left over.