Question 1

When the following equation is balanced, the coefficients are ________. C8H18 + O2 → CO2 + H2O

Accepted Answer

A)  4, 50, 16, 18
B)  1, 5, 2, 2
C)  2, 2, 7, 1
D)  1, 13, 8, 9
E)  2, 25, 16, 18F) A) and E)
G) A) and C)

Question 2

The combustion of carbon disulfide in the presence of excess oxygen yields carbon dioxide and sulfur dioxide:
CS2 (g) + 3O2 (g) → CO2 (g) + 2SO2 (g)
The combustion of 15 g of CS2 in the presence of excess oxygen yields ________ g of SO2.

Accepted Answer

Question 3

A sample of C3H8O that contains 200 molecules contains ________ carbon atoms.

Accepted Answer

A)  600
B)  200
C)  3.61 × 1026
D)  1.20 × 1026
E)  4.01 × 1025F) B) and C)
G) None of the above

Question 4

Water can be formed from the stoichiometric reaction of hydrogen with oxygen:
2H2 (g) + O2 (g) → 2H2O (g)
A complete reaction of 5.0 g of O2 with excess hydrogen produces ________ g of H2O.

Accepted Answer

Question 5

How many moles of lithium phosphate (Li3PO4) are contained in 66.6 g of lithium phosphate?

Accepted Answer

A)  0.575
B)  7710
C)  1.11 × 10-22
D)  4.01 × 1025
E)  116F) All of the above
G) B) and C)

Question 6

Calcium oxide reacts with water in a combination reaction to produce calcium hydroxide: CaO (s)  + H2O (l)  → Ca(OH) 2 (s) 
A 3.50-g sample of CaO is reacted with 3.38 g of H2O. How many grams of water remain after completion of reaction?

Accepted Answer

A)  0.00
B)  0.00694
C)  2.25
D)  1.04
E)  0.125F) C) and D)
G) A) and E)

Question 7

There are ________ oxygen atoms in 30 molecules of C20H42S3O2.

Accepted Answer

A)  6.0 × 1023
B)  1.8 × 1025
C)  3.6 × 1025
D)  1.2 × 1024
E)  60F) A) and B)
G) A) and E)

Question 8

How many moles of sodium carbonate contain 1.773 × 1017 carbon atoms?

Accepted Answer

A)  5.890 × 10-7
B)  2.945 × 10-7
C)  1.473 × 10-7
D)  8.836 × 10-7
E)  9.817 × 10-8F) A) and B)
G) A) and C)

Question 9

Calcium oxide reacts with water in a combination reaction to produce calcium hydroxide: CaO (s)  + H2O (l)  → Ca(OH) 2 (s) 
In a particular experiment, a 2.00-g sample of CaO is reacted with excess water and 2.14 g of Ca(OH) 2 is recovered. What is the percent yield in this experiment?

Accepted Answer

A)  107
B)  1.07
C)  2.88
D)  81.1
E)  93.3F) A) and E)
G) A) and D)

Question 10

Sulfur and oxygen react to produce sulfur trioxide. In a particular experiment, 7.9 grams of SO3 are produced by the reaction of 6.0 grams of O2 with 7.0 grams of S. What is the % yield of SO3 in this experiment? S (s)  + O2 (g)  → SO3 (g)  (not balanced)

Accepted Answer

A)  48
B)  62
C)  73
D)  79
E)  92F) C) and D)
G) All of the above

Question 11

What is the mass in grams of 9.76 × 1012 atoms of naturally occurring potassium?

Accepted Answer

A)  2.41 × 1012
B)  2.50 × 1011
C)  6.34 × 10-10
D)  1.62 × 10-11
E)  3.82 × 1014F) A) and E)
G) B) and C)

Question 12

A compound contains 40.0% C, 6.71% H, and 53.29% O by mass. The molecular weight of the compound is 60.05 amu. The molecular formula of this compound is ________.

Accepted Answer

A)  C2H4O2
B)  CH2O
C)  C2H3O4
D)  C2H2O4
E)  CHO2F) None of the above
G) B) and E)

Question 13

Lead (II) carbonate decomposes to give lead (II) oxide and carbon dioxide: PbCO3 (s)  → PbO (s)  + CO2 (g) 
________ grams of lead (II) oxide will be produced by the decomposition of 8.75 g of lead (II) carbonate?

Accepted Answer

A)  0.41
B)  2.50
C)  0.00936
D)  7.31
E)  11.7F) A) and B)
G) A) and C)

Question 14

A 1.36-g sample of magnesium nitrate, Mg(NO3) 2, contains ________ mol of this compound.

Accepted Answer

A)  2.32
B)  1.65
C)  0.111
D)  0.0182
E)  0.00917F) B) and C)
G) A) and E)

Question 15

Under appropriate conditions, nitrogen and hydrogen undergo a combination reaction to yield ammonia: N2 (g)  + 3H2 (g)  → 2NH3 (g) 
If the reaction yield is 87.5%, how many moles of N2 are needed to produce 3.00 mol of NH3?

Accepted Answer

A)  0.166
B)  1.00
C)  1.5
D)  1.71
E)  2.32F) A) and B)
G) A) and C)

Question 16

If the reaction yield is 94.4%, what mass in grams of hydrogen is produced by the reaction of 4.73 g of magnesium with 1.83 g of water? Mg (s)  + 2H2O (l)  → Mg(OH) 2 (s)  + H2 (g)

Accepted Answer

A)  0.0962
B)  0.0162
C)  0.0485
D)  0.219
E)  0.204F) All of the above
G) None of the above

Question 17

Which one of the following is not true concerning automotive air bags?

Accepted Answer

A)  They are inflated as a result of a decomposition reaction.
B)  They are loaded with sodium azide initially.
C)  The gas used for inflating them is oxygen.
D)  The two products of the decomposition reaction are sodium and nitrogen.
E)  A gas is produced when the air bag activates.F) A) and B)
G) B) and E)

Question 18

Solid aluminum and gaseous oxygen react in a combination reaction to produce aluminum oxide: 4Al (s)  + 3O2 (g)  → 2Al2O3 (s) 
In a particular experiment, the reaction of 2.5 g of Al with 2.5 g of O2 produced 3.5 g of Al2O3. The % yield of the reaction is ________.

Accepted Answer

A)  74
B)  37
C)  47
D)  66
E)  26F) A) and E)
G) A) and D)

Question 19

Sulfur and fluorine react in a combination reaction to produce sulfur hexafluoride: S (s)  + 3F2 (g)  → SF6 (g) 
In a particular experiment, the percent yield is 79.0%. This means that in this experiment, a 7.90-g sample of fluorine yields ________ g of SF6.

Accepted Answer

A)  30.3
B)  10.1
C)  7.99
D)  24.0
E)  0.110F) A) and E)
G) A) and D)

Question 20

Calculate the percentage by mass of lead in Pb(NO3) 2.

Accepted Answer

A)  38.6
B)  44.5
C)  62.6
D)  65.3
E)  71.2F) A) and B)
G) A) and E)

Exam 3: Stoichiometry: Calculations With Chemical Formulas and Equations

Under appropriate conditions, nitrogen and hydrogen undergo a combination reaction to yield ammonia: N2 (g) + 3H2 (g) → 2NH3 (g) If the reaction yield is 87.5%, how many moles of N2 are needed to produce 3.00 mol of NH3?

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Calculate the percentage by mass of lead in Pb(NO3) 2.

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When the following equation is balanced, the coefficients are ________. C8H18 + O2 → CO2 + H2O

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Water can be formed from the stoichiometric reaction of hydrogen with oxygen: 2H2 (g) + O2 (g) → 2H2O (g) A complete reaction of 5.0 g of O2 with excess hydrogen produces ________ g of H2O.

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How many moles of sodium carbonate contain 1.773 × 1017 carbon atoms?

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Lead (II) carbonate decomposes to give lead (II) oxide and carbon dioxide: PbCO3 (s) → PbO (s) + CO2 (g) ________ grams of lead (II) oxide will be produced by the decomposition of 8.75 g of lead (II) carbonate?

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Which one of the following is not true concerning automotive air bags?

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How many moles of lithium phosphate (Li3PO4) are contained in 66.6 g of lithium phosphate?

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A compound contains 40.0% C, 6.71% H, and 53.29% O by mass. The molecular weight of the compound is 60.05 amu. The molecular formula of this compound is ________.

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A 1.36-g sample of magnesium nitrate, Mg(NO3) 2, contains ________ mol of this compound.

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Sulfur and fluorine react in a combination reaction to produce sulfur hexafluoride: S (s) + 3F2 (g) → SF6 (g) In a particular experiment, the percent yield is 79.0%. This means that in this experiment, a 7.90-g sample of fluorine yields ________ g of SF6.

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If the reaction yield is 94.4%, what mass in grams of hydrogen is produced by the reaction of 4.73 g of magnesium with 1.83 g of water? Mg (s) + 2H2O (l) → Mg(OH) 2 (s) + H2 (g)

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Solid aluminum and gaseous oxygen react in a combination reaction to produce aluminum oxide: 4Al (s) + 3O2 (g) → 2Al2O3 (s) In a particular experiment, the reaction of 2.5 g of Al with 2.5 g of O2 produced 3.5 g of Al2O3. The % yield of the reaction is ________.

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Sulfur and oxygen react to produce sulfur trioxide. In a particular experiment, 7.9 grams of SO3 are produced by the reaction of 6.0 grams of O2 with 7.0 grams of S. What is the % yield of SO3 in this experiment? S (s) + O2 (g) → SO3 (g) (not balanced)

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The combustion of carbon disulfide in the presence of excess oxygen yields carbon dioxide and sulfur dioxide: CS2 (g) + 3O2 (g) → CO2 (g) + 2SO2 (g) The combustion of 15 g of CS2 in the presence of excess oxygen yields ________ g of SO2.

Correct AnswerverifiedShow Answer

Calcium oxide reacts with water in a combination reaction to produce calcium hydroxide: CaO (s) + H2O (l) → Ca(OH) 2 (s) In a particular experiment, a 2.00-g sample of CaO is reacted with excess water and 2.14 g of Ca(OH) 2 is recovered. What is the percent yield in this experiment?

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Calcium oxide reacts with water in a combination reaction to produce calcium hydroxide: CaO (s) + H2O (l) → Ca(OH) 2 (s) A 3.50-g sample of CaO is reacted with 3.38 g of H2O. How many grams of water remain after completion of reaction?

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A sample of C3H8O that contains 200 molecules contains ________ carbon atoms.

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What is the mass in grams of 9.76 × 1012 atoms of naturally occurring potassium?

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There are ________ oxygen atoms in 30 molecules of C20H42S3O2.

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Under appropriate conditions, nitrogen and hydrogen undergo a combination reaction to yield ammonia: N₂ (g) + 3H₂ (g) → 2NH₃ (g) If the reaction yield is 87.5%, how many moles of N₂ are needed to produce 3.00 mol of NH₃?

Correct Answer
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Calculate the percentage by mass of lead in Pb(NO₃) ₂.

Correct Answer
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When the following equation is balanced, the coefficients are ________. C₈H₁₈ + O₂ → CO₂ + H₂O

Correct Answer
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Water can be formed from the stoichiometric reaction of hydrogen with oxygen: 2H₂ (g) + O₂ (g) → 2H₂O (g) A complete reaction of 5.0 g of O₂ with excess hydrogen produces ________ g of H₂O.

Correct Answer
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How many moles of sodium carbonate contain 1.773 × 10¹⁷ carbon atoms?

Correct Answer
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Lead (II) carbonate decomposes to give lead (II) oxide and carbon dioxide: PbCO₃ (s) → PbO (s) + CO₂ (g) ________ grams of lead (II) oxide will be produced by the decomposition of 8.75 g of lead (II) carbonate?

Correct Answer
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Correct Answer
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How many moles of lithium phosphate (Li₃PO₄) are contained in 66.6 g of lithium phosphate?

Correct Answer
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Correct Answer
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A 1.36-g sample of magnesium nitrate, Mg(NO₃) ₂, contains ________ mol of this compound.

Correct Answer
verified

Sulfur and fluorine react in a combination reaction to produce sulfur hexafluoride: S (s) + 3F₂ (g) → SF₆ (g) In a particular experiment, the percent yield is 79.0%. This means that in this experiment, a 7.90-g sample of fluorine yields ________ g of SF₆.

Correct Answer
verified

If the reaction yield is 94.4%, what mass in grams of hydrogen is produced by the reaction of 4.73 g of magnesium with 1.83 g of water? Mg (s) + 2H₂O (l) → Mg(OH) ₂ (s) + H₂ (g)

Correct Answer
verified

Solid aluminum and gaseous oxygen react in a combination reaction to produce aluminum oxide: 4Al (s) + 3O₂ (g) → 2Al₂O₃ (s) In a particular experiment, the reaction of 2.5 g of Al with 2.5 g of O₂ produced 3.5 g of Al₂O₃. The % yield of the reaction is ________.

Correct Answer
verified

Sulfur and oxygen react to produce sulfur trioxide. In a particular experiment, 7.9 grams of SO₃ are produced by the reaction of 6.0 grams of O₂ with 7.0 grams of S. What is the % yield of SO₃ in this experiment? S (s) + O₂ (g) → SO₃ (g) (not balanced)

Correct Answer
verified

The combustion of carbon disulfide in the presence of excess oxygen yields carbon dioxide and sulfur dioxide: CS₂ (g) + 3O₂ (g) → CO₂ (g) + 2SO₂ (g) The combustion of 15 g of CS₂ in the presence of excess oxygen yields ________ g of SO₂.

Correct Answer
verified

Calcium oxide reacts with water in a combination reaction to produce calcium hydroxide: CaO (s) + H₂O (l) → Ca(OH) ₂ (s) In a particular experiment, a 2.00-g sample of CaO is reacted with excess water and 2.14 g of Ca(OH) ₂ is recovered. What is the percent yield in this experiment?

Correct Answer
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Calcium oxide reacts with water in a combination reaction to produce calcium hydroxide: CaO (s) + H₂O (l) → Ca(OH) ₂ (s) A 3.50-g sample of CaO is reacted with 3.38 g of H₂O. How many grams of water remain after completion of reaction?

Correct Answer
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A sample of C₃H₈O that contains 200 molecules contains ________ carbon atoms.

Correct Answer
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What is the mass in grams of 9.76 × 10¹² atoms of naturally occurring potassium?

Correct Answer
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There are ________ oxygen atoms in 30 molecules of C₂₀H₄₂S₃O₂.

Correct Answer
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