Question 1

Calcium fluoride, CaF2, is a source of fluorine and is used to fluoridate drinking water. Calculate its molar mass.

Accepted Answer

A)   118.15 g/mol
B)   99.15 g/mol
C)   78.07 g/mol
D)   59.08 g/mol
E)   50.01 g/molF) D) and E)
G) A) and E)

Question 2

How many grams of oxygen are needed to react completely with 200.0 g of ammonia, NH3? 4NH3(g)  + 5O2(g)  → 4NO(g)  + 6H2O(g)

Accepted Answer

A)   469.7 g
B)   300.6 g
C)   250.0 g
D)   3.406 g
E)   2.180 gF) A) and B)
G) D) and E)

Question 3

Calculate the molar mass of Ca(BO2) 2·6H2O.

Accepted Answer

A)   273.87 g/mol
B)   233.79 g/mol
C)   183.79 g/mol
D)   174.89 g/mol
E)   143.71 g/molF) A) and C)
G) A) and E)

Question 4

In the combustion analysis of 0.1127 g of glucose (C6H12O6) , what mass, in grams, of CO2 would be produced?

Accepted Answer

A)   0.0451 g
B)   0.0825 g
C)   0.1652 g
D)   0.4132 g
E)   1.466 gF) B) and D)
G) A) and E)

Question 5

Potassium dichromate, K2Cr2O7, is used in tanning leather, decorating porcelain, and water proofing fabrics. Calculate the number of chromium atoms in 78.82 g of K2Cr2O7.

Accepted Answer

A)   9.490 × 1025 Cr atoms
B)   2.248 × 1024 Cr atoms
C)   1.124 × 1024 Cr atoms
D)   3.227 × 1023 Cr atoms
E)   1.613 × 1023 Cr atomsF) D) and E)
G) A) and B)

Question 6

Magnesium fluoride is used in the ceramics and glass industry. What is the mass of 1.72 mol of magnesium fluoride?

Accepted Answer

A)   43.3 g
B)   62.3 g
C)   74.5 g
D)   92.9 g
E)   107 gF) C) and E)
G) A) and E)

Question 7

Determine the percent composition of potassium dichromate, K2Cr2O7.

Accepted Answer

A)   17.5% K, 46.6% Cr, 35.9% O
B)   29.8% K, 39.7% Cr, 30.5% O
C)   36.5% K, 48.6% Cr, 14.9% O
D)   37.2% K, 24.7% Cr, 38.1% O
E)   None of these choices are correct.F) C) and D)
G) B) and D)

Question 8

How many grams of sodium fluoride (used in water fluoridation and manufacture of insecticides)  are needed to form 485 g of sulfur tetrafluoride? 3SCl2(l)  + 4NaF(s)  → SF4(g)  + S2Cl2(l)  + 4NaCl(s)

Accepted Answer

A)   1940 g
B)   1510 g
C)   754 g
D)   205 g
E)   51.3 gF) A) and B)
G) B) and D)

Question 9

Hydroxylamine nitrate contains 29.17 mass % N, 4.20 mass % H, and 66.63 mass % O. Determine its empirical formula.

Accepted Answer

A)   HNO
B)   H2NO2
C)   HN6O16
D)   HN16O7
E)   H2NO3F) A) and B)
G) A) and E)

Question 10

In a blast furnace, elemental iron is produced from a mixture of coke (C) , iron ore (Fe3O4) , and other reactants. An important reaction sequence is 2C(s)  + O2(g)  → 2CO(g) 
Fe3O4(s)  + 4CO(g)  → 3Fe(l)  + 4CO2(g) 
How many moles of iron can be formed in this sequence when 1.00 mol of carbon, as coke, is consumed?

Accepted Answer

A)   6.00 mol Fe
B)   3.00 mol Fe
C)   1.33 mol Fe
D)   1.25 mol Fe
E)   0.750 mol FeF) B) and E)
G) A) and B)

Question 11

Balance the following equation for the combustion of benzene: C6H6(l)  + O2(g)  → H2O(g)  + CO2(g)

Accepted Answer

A)   C6H6(l)  + 9O2(g)  → 3H2O(g)  + 6CO2(g) 
B)   C6H6(l)  + 9O2(g)  → 6H2O(g)  + 6CO2(g) 
C)   2C6H6(l)  + 15O2(g)  → 6H2O(g)  + 12CO2(g) 
D)   C6H6(l)  + 15O2(g)  → 3H2O(g)  + 6CO2(g) 
E)   2C6H6(l)  + 9O2(g)  → 6H2O(g)  + 12CO2(g) F) C) and E)
G) A) and E)

Question 12

Gadolinium oxide, a colorless powder which absorbs carbon dioxide from the air, contains 86.76 mass % Gd. Determine its empirical formula.

Accepted Answer

A)   Gd2O3
B)   Gd3O2
C)   Gd3O4
D)   Gd4O3
E)   GdOF) B) and C)
G) A) and E)

Question 13

Aluminum reacts with oxygen to produce aluminum oxide which can be used as an adsorbent, desiccant, or catalyst for organic reactions. 4Al(s)  + 3O2(g)  → 2Al2O3(s) 
A mixture of 82.49 g of aluminum ( 2(g)  → 2Al2O3(s)  A mixture of 82.49 g of aluminum (   = 26.98 g/mol)  and 117.65 g of oxygen (   = 32.00 g/mol)  is allowed to react. Identify the limiting reactant and determine the mass of the excess reactant present in the vessel when the reaction is complete. A)  Oxygen is the limiting reactant; 19.81 g of aluminum remain. B)  Oxygen is the limiting reactant; 35.16 g of aluminum remain. C)  Aluminum is the limiting reactant; 16.70 g of oxygen remain. D)  Aluminum is the limiting reactant; 35.16 g of oxygen remain. E)  Aluminum is the limiting reactant; 44.24 g of oxygen remain." class="answers-bank-image d-inline" rel="preload" > = 26.98 g/mol)  and 117.65 g of oxygen ( 2(g)  → 2Al2O3(s)  A mixture of 82.49 g of aluminum (   = 26.98 g/mol)  and 117.65 g of oxygen (   = 32.00 g/mol)  is allowed to react. Identify the limiting reactant and determine the mass of the excess reactant present in the vessel when the reaction is complete. A)  Oxygen is the limiting reactant; 19.81 g of aluminum remain. B)  Oxygen is the limiting reactant; 35.16 g of aluminum remain. C)  Aluminum is the limiting reactant; 16.70 g of oxygen remain. D)  Aluminum is the limiting reactant; 35.16 g of oxygen remain. E)  Aluminum is the limiting reactant; 44.24 g of oxygen remain." class="answers-bank-image d-inline" rel="preload" > = 32.00 g/mol)  is allowed to react. Identify the limiting reactant and determine the mass of the excess reactant present in the vessel when the reaction is complete.

Accepted Answer

A)   Oxygen is the limiting reactant; 19.81 g of aluminum remain.
B)   Oxygen is the limiting reactant; 35.16 g of aluminum remain.
C)   Aluminum is the limiting reactant; 16.70 g of oxygen remain.
D)   Aluminum is the limiting reactant; 35.16 g of oxygen remain.
E)   Aluminum is the limiting reactant; 44.24 g of oxygen remain.F) A) and D)
G) D) and E)

Question 14

Lead (II)  nitrate is a poisonous substance which has been used in the manufacture of special explosives and as a sensitizer in photography. Calculate the mass of lead in 139 g of Pb(NO3) 2.

Accepted Answer

A)   107 g
B)   90.8 g
C)   87.0 g
D)   83.4 g
E)   62.6 gF) A) and B)
G) C) and E)

Question 15

Lead(II)  sulfide was once used in glazing earthenware. It will also react with hydrogen peroxide to form lead(II)  sulfate and water. How many grams of hydrogen peroxide are needed to react completely with 265 g of lead(II)  sulfide?

Accepted Answer

A)   151 g
B)   123 g
C)   50.3 g
D)   37.7 g
E)   9.41 gF) All of the above
G) B) and D)

Question 16

Potassium chlorate (used in fireworks, flares, and safety matches)  forms oxygen and potassium chloride when heated. KClO3(s)  → KCl(s)  + O2(g)  [unbalanced]
How many grams of oxygen are formed when 26.4 g of potassium chlorate is heated?

Accepted Answer

A)   223 g
B)   99.1 g
C)   10.3 g
D)   6.86 g
E)   4.60 gF) None of the above
G) A) and D)

Question 17

An important reaction sequence in the industrial production of nitric acid is the following: N2(g)  + 3H2(g)  → 2NH3(g) 
4NH3(g)  + 5O2(g)  → 4NO(g)  + 6H2O(l) 
Starting from 20.0 mol of nitrogen gas in the first reaction, how many moles of oxygen gas are required in the second one?

Accepted Answer

A)   12.5 mol O2
B)   20.0 mol O2
C)   25.0 mol O2
D)   50.0 mol O2
E)   100. mol O2F) B) and C)
G) C) and D)

Question 18

In a correctly balanced equation, the number of reactant molecules must equal the number of product molecules.

Accepted Answer

A) True 
 B)False

Question 19

Copper(II)  sulfate pentahydrate, CuSO4·5H2O, is used as a fungicide and algicide. Calculate the mass of oxygen in 1.000 mol of CuSO4·5H2O.

Accepted Answer

A)   249.7 g
B)   144.0 g
C)   96.00 g
D)   80.00 g
E)   64.00 gF) A) and B)
G) A) and C)

Question 20

The formula CH3O0.5 is an example of an empirical formula.

Accepted Answer

A) True 
 B)False

Exam 3: Stoichiometry of Formulas and Equations

Calcium fluoride, CaF₂, is a source of fluorine and is used to fluoridate drinking water. Calculate its molar mass.

Correct Answer
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Correct Answer
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Gadolinium oxide, a colorless powder which absorbs carbon dioxide from the air, contains 86.76 mass % Gd. Determine its empirical formula.

Correct Answer
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Potassium chlorate (used in fireworks, flares, and safety matches) forms oxygen and potassium chloride when heated. KClO₃(s) → KCl(s) + O₂(g) [unbalanced] How many grams of oxygen are formed when 26.4 g of potassium chlorate is heated?

Correct Answer
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Correct Answer
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Hydroxylamine nitrate contains 29.17 mass % N, 4.20 mass % H, and 66.63 mass % O. Determine its empirical formula.

Correct Answer
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Calculate the molar mass of Ca(BO₂) ₂·6H₂O.

Correct Answer
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Copper(II) sulfate pentahydrate, CuSO₄·5H₂O, is used as a fungicide and algicide. Calculate the mass of oxygen in 1.000 mol of CuSO₄·5H₂O.

Correct Answer
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How many grams of sodium fluoride (used in water fluoridation and manufacture of insecticides) are needed to form 485 g of sulfur tetrafluoride? 3SCl₂(l) + 4NaF(s) → SF₄(g) + S₂Cl₂(l) + 4NaCl(s)

Correct Answer
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How many grams of oxygen are needed to react completely with 200.0 g of ammonia, NH₃? 4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(g)

Correct Answer
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Balance the following equation for the combustion of benzene: C₆H₆(l) + O₂(g) → H₂O(g) + CO₂(g)

Correct Answer
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An important reaction sequence in the industrial production of nitric acid is the following: N₂(g) + 3H₂(g) → 2NH₃(g) 4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(l) Starting from 20.0 mol of nitrogen gas in the first reaction, how many moles of oxygen gas are required in the second one?

Correct Answer
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Lead(II) sulfide was once used in glazing earthenware. It will also react with hydrogen peroxide to form lead(II) sulfate and water. How many grams of hydrogen peroxide are needed to react completely with 265 g of lead(II) sulfide?

Correct Answer
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Potassium dichromate, K₂Cr₂O₇, is used in tanning leather, decorating porcelain, and water proofing fabrics. Calculate the number of chromium atoms in 78.82 g of K₂Cr₂O₇.

Correct Answer
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The formula CH₃O_0.5 is an example of an empirical formula.

Correct Answer
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Magnesium fluoride is used in the ceramics and glass industry. What is the mass of 1.72 mol of magnesium fluoride?

Correct Answer
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Lead (II) nitrate is a poisonous substance which has been used in the manufacture of special explosives and as a sensitizer in photography. Calculate the mass of lead in 139 g of Pb(NO₃) ₂.

Correct Answer
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In a correctly balanced equation, the number of reactant molecules must equal the number of product molecules.

Correct Answer
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Determine the percent composition of potassium dichromate, K₂Cr₂O₇.

Correct Answer
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In the combustion analysis of 0.1127 g of glucose (C₆H₁₂O₆) , what mass, in grams, of CO₂ would be produced?

Correct Answer
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Exam 3: Stoichiometry of Formulas and Equations

Calcium fluoride, CaF2, is a source of fluorine and is used to fluoridate drinking water. Calculate its molar mass.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Gadolinium oxide, a colorless powder which absorbs carbon dioxide from the air, contains 86.76 mass % Gd. Determine its empirical formula.

Correct AnswerverifiedShow Answer

Potassium chlorate (used in fireworks, flares, and safety matches) forms oxygen and potassium chloride when heated. KClO3(s) → KCl(s) + O2(g) [unbalanced] How many grams of oxygen are formed when 26.4 g of potassium chlorate is heated?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Hydroxylamine nitrate contains 29.17 mass % N, 4.20 mass % H, and 66.63 mass % O. Determine its empirical formula.

Correct AnswerverifiedShow Answer

Calculate the molar mass of Ca(BO2) 2·6H2O.

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Copper(II) sulfate pentahydrate, CuSO4·5H2O, is used as a fungicide and algicide. Calculate the mass of oxygen in 1.000 mol of CuSO4·5H2O.

Correct AnswerverifiedShow Answer

How many grams of sodium fluoride (used in water fluoridation and manufacture of insecticides) are needed to form 485 g of sulfur tetrafluoride? 3SCl2(l) + 4NaF(s) → SF4(g) + S2Cl2(l) + 4NaCl(s)

Correct AnswerverifiedShow Answer

How many grams of oxygen are needed to react completely with 200.0 g of ammonia, NH3? 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g)

Correct AnswerverifiedShow Answer

Balance the following equation for the combustion of benzene: C6H6(l) + O2(g) → H2O(g) + CO2(g)

Correct AnswerverifiedShow Answer

An important reaction sequence in the industrial production of nitric acid is the following: N2(g) + 3H2(g) → 2NH3(g) 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(l) Starting from 20.0 mol of nitrogen gas in the first reaction, how many moles of oxygen gas are required in the second one?

Correct AnswerverifiedShow Answer

Lead(II) sulfide was once used in glazing earthenware. It will also react with hydrogen peroxide to form lead(II) sulfate and water. How many grams of hydrogen peroxide are needed to react completely with 265 g of lead(II) sulfide?

Correct AnswerverifiedShow Answer

Potassium dichromate, K2Cr2O7, is used in tanning leather, decorating porcelain, and water proofing fabrics. Calculate the number of chromium atoms in 78.82 g of K2Cr2O7.

Correct AnswerverifiedShow Answer

The formula CH3O0.5 is an example of an empirical formula.

Correct AnswerverifiedShow Answer

Magnesium fluoride is used in the ceramics and glass industry. What is the mass of 1.72 mol of magnesium fluoride?

Correct AnswerverifiedShow Answer

Lead (II) nitrate is a poisonous substance which has been used in the manufacture of special explosives and as a sensitizer in photography. Calculate the mass of lead in 139 g of Pb(NO3) 2.

Correct AnswerverifiedShow Answer

In a correctly balanced equation, the number of reactant molecules must equal the number of product molecules.

Correct AnswerverifiedShow Answer

Determine the percent composition of potassium dichromate, K2Cr2O7.

Correct AnswerverifiedShow Answer

In the combustion analysis of 0.1127 g of glucose (C6H12O6) , what mass, in grams, of CO2 would be produced?

Correct AnswerverifiedShow Answer

Calcium fluoride, CaF₂, is a source of fluorine and is used to fluoridate drinking water. Calculate its molar mass.

Correct Answer
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Correct Answer
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Correct Answer
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Potassium chlorate (used in fireworks, flares, and safety matches) forms oxygen and potassium chloride when heated. KClO₃(s) → KCl(s) + O₂(g) [unbalanced] How many grams of oxygen are formed when 26.4 g of potassium chlorate is heated?

Correct Answer
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Correct Answer
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Correct Answer
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Calculate the molar mass of Ca(BO₂) ₂·6H₂O.

Correct Answer
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Copper(II) sulfate pentahydrate, CuSO₄·5H₂O, is used as a fungicide and algicide. Calculate the mass of oxygen in 1.000 mol of CuSO₄·5H₂O.

Correct Answer
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How many grams of sodium fluoride (used in water fluoridation and manufacture of insecticides) are needed to form 485 g of sulfur tetrafluoride? 3SCl₂(l) + 4NaF(s) → SF₄(g) + S₂Cl₂(l) + 4NaCl(s)

Correct Answer
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How many grams of oxygen are needed to react completely with 200.0 g of ammonia, NH₃? 4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(g)

Correct Answer
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Balance the following equation for the combustion of benzene: C₆H₆(l) + O₂(g) → H₂O(g) + CO₂(g)

Correct Answer
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An important reaction sequence in the industrial production of nitric acid is the following: N₂(g) + 3H₂(g) → 2NH₃(g) 4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(l) Starting from 20.0 mol of nitrogen gas in the first reaction, how many moles of oxygen gas are required in the second one?

Correct Answer
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Correct Answer
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Potassium dichromate, K₂Cr₂O₇, is used in tanning leather, decorating porcelain, and water proofing fabrics. Calculate the number of chromium atoms in 78.82 g of K₂Cr₂O₇.

Correct Answer
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The formula CH₃O_0.5 is an example of an empirical formula.

Correct Answer
verified

Correct Answer
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Lead (II) nitrate is a poisonous substance which has been used in the manufacture of special explosives and as a sensitizer in photography. Calculate the mass of lead in 139 g of Pb(NO₃) ₂.

Correct Answer
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Correct Answer
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Determine the percent composition of potassium dichromate, K₂Cr₂O₇.

Correct Answer
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In the combustion analysis of 0.1127 g of glucose (C₆H₁₂O₆) , what mass, in grams, of CO₂ would be produced?

Correct Answer
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