Question 1

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 2

What is the mass % of carbon in dimethylsulfoxide (C2H6SO) rounded to three significant figures?

Accepted Answer

A)  60.0
B)  20.6
C)  30.7
D)  7.74
E)  79.8F) B) and D)
G) A) and D)

Question 3

A great deal of the carbon dioxide produced by the combustion of fossil fuels is absorbed into the oceans.

Accepted Answer

A) True 
 B)False

Question 4

The combustion of propane (C3H8) produces CO2 and H2O: C3H8 (g) + 5 O2 (g) → 3CO2 (g) + 4 H2O (g) 
The reaction of 2.5 mol of O2 with 4.6 mol of C3H8 will produce __________ mol of H2O.

Accepted Answer

A)  4.0
B)  3.0
C)  2.5
D)  2.0
E)  1.0F) None of the above
G) A) and E)

Question 5

Which of the following are combustion reactions?
1) CH4 (g) + O2 (g) → CO2 (g) + H2O (l) 
2) CaO (s) + CO2 (g) → CaCO3 (s) 
3) PbCO3 (s) → PbO (s) + CO2 (g) 
4) CH3OH (l) + O2 (g) → CO2 (g) + H2O (l)

Accepted Answer

A)  1 and 4
B)  1, 2, 3, and 4
C)  1, 3, and 4
D)  2, 3, and 4
E)  3 and 4F) A) and E)
G) A) and C)

Question 6

Lithium and nitrogen react in a combination reaction to produce lithium nitride: 6Li (s) + N2 (g) → 2Li3N (s) 
How many moles of lithium are needed to produce 0.20 mol of Li3N when the reaction is carried out in the presence of excess nitrogen?

Accepted Answer

A)  0.10
B)  0.60
C)  0.067
D)  0.13
E)  1.2F) D) and E)
G) A) and D)

Question 7

Magnesium burns in air with a dazzling brilliance to produce magnesium oxide: 2Mg (s) + O2 (g) → 2MgO (s) 
How many moles of O2 are consumed when 4.11 mol of magnesium burns?

Accepted Answer

A)  0.169
B)  0.487
C)  4.11
D)  8.22
E)  2.06F) None of the above
G) A) and B)

Question 8

Predict the product in the combination reaction below. Al (s) + N2 (g) → __________

Accepted Answer

A)  AlN
B)  Al3N
C)  Al N2
D)  Al3N2
E)  AlN3F) A) and D)
G) D) and E)

Question 9

Lead (II) carbonate decomposes to give lead (II) oxide and carbon dioxide: PbCO3 (s) → PbO (s) + CO2 (g) 
How many grams of lead (II) oxide will be produced by the decomposition of 2.50 g of lead (II) carbonate?

Accepted Answer

A)  0.41
B)  2.50
C)  0.00936
D)  2.09
E)  2.61F) A) and E)
G) All of the above

Question 10

There are __________ mol of carbon atoms in 3 mol of dimethylsulfoxide (C2H6SO) .

Accepted Answer

A)  2
B)  4
C)  6
D)  8
E)  10F) B) and E)
G) A) and E)

Question 11

How many moles of magnesium oxide are produced by the reaction of 3.82 g of magnesium nitride with 7.73 g of water? Mg3N2 + 3 H2O → 2NH3 + 3MgO

Accepted Answer

A)  0.114
B)  0.0378
C)  0.429
D)  0.0756
E)  4.57F) C) and E)
G) A) and E)

Question 12

Sulfur and fluorine react in a combination reaction to produce sulfur hexafluoride: S (s) + 3 F3 (g) → SF6 (g) 
The maximum amount of SF6 that can be produced from the reaction of 3.5 g of sulfur with 4.5 g of fluorine is __________ g.

Accepted Answer

A)  12
B)  3.2
C)  5.8
D)  16
E)  8.0F) D) and E)
G) A) and B)

Question 13

Calcium carbide (CaC2) reacts with water to produce acetylene (C2H2) : CaC2 (s) + 2 H2O (g) → Ca(OH) 2 (s) + C2H2 (g) 
Production of 3.3 g of C2H2 requires consumption of __________ g of H2O.

Accepted Answer

A)  1.2
B)  2.3
C)  4.6
D)  480
E)  0.048F) A) and E)
G) C) and E)

Question 14

How many moles of carbon monoxide are there in 36.55 g of carbon monoxide?

Accepted Answer

A)  0.8452
B)  1.305
C)  0.9291
D)  2.589
E)  3.046F) A) and E)
G) A) and D)

Question 15

The formula weight of potassium dichromate (K2Cr2O7) is __________ amu.

Accepted Answer

A)  107.09
B)  255.08
C)  242.18
D)  294.18
E)  333.08F) All of the above
G) None of the above

Question 16

When the following equation is balanced, the coefficient of HNO3 is __________. HNO3 (aq) + CaCO3 (s) → Ca(NO3) 2 (aq) + CO2 (g) + H2O (l)

Accepted Answer

A)  1
B)  2
C)  3
D)  5
E)  4F) B) and C)
G) A) and E)

Question 17

The reaction used to inflate automobile airbags __________.

Accepted Answer

A)  produces sodium gas
B)  is a combustion reaction
C)  is a combination reaction
D)  violates the law of conservation of mass
E)  is a decomposition reactionF) A) and B)
G) C) and D)

Question 18

There are __________ molecules of methane in 0.123 mol of methane (CH4) .

Accepted Answer

A)  5
B)  2.46 × 10-2
C)  2.04 × 10-25
D)  7.40 × 1022
E)  0.615F) A) and B)
G) None of the above

Question 19

When the following equation is balanced, the coefficient of H3PO4 is __________. H3PO4 (aq) + NaOH (aq) → Na3PO4 (aq) + H2O (l)

Accepted Answer

A)  1
B)  2
C)  3
D)  4
E)  0F) A) and E)
G) B) and D)

Question 20

The formula weight of potassium phosphate (K3PO4) is __________ amu.

Accepted Answer

A)  173.17
B)  251.37
C)  212.27
D)  196.27
E)  86.07F) B) and E)
G) B) and D)

Exam 3: Stoichiometry: Calculations With Chemical Formulas and Equations

When the following equation is balanced, the coefficient of HNO3 is __________. HNO3 (aq) + CaCO3 (s) → Ca(NO3) 2 (aq) + CO2 (g) + H2O (l)

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When the following equation is balanced, the coefficient of H3PO4 is __________. H3PO4 (aq) + NaOH (aq) → Na3PO4 (aq) + H2O (l)

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The reaction used to inflate automobile airbags __________.

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The formula weight of potassium phosphate (K3PO4) is __________ amu.

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Magnesium burns in air with a dazzling brilliance to produce magnesium oxide: 2Mg (s) + O2 (g) → 2MgO (s) How many moles of O2 are consumed when 4.11 mol of magnesium burns?

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There are __________ mol of carbon atoms in 3 mol of dimethylsulfoxide (C2H6SO) .

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Which of the following are combustion reactions? 1) CH4 (g) + O2 (g) → CO2 (g) + H2O (l) 2) CaO (s) + CO2 (g) → CaCO3 (s) 3) PbCO3 (s) → PbO (s) + CO2 (g) 4) CH3OH (l) + O2 (g) → CO2 (g) + H2O (l)

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How many moles of carbon monoxide are there in 36.55 g of carbon monoxide?

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A great deal of the carbon dioxide produced by the combustion of fossil fuels is absorbed into the oceans.

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Predict the product in the combination reaction below. Al (s) + N2 (g) → __________

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The formula weight of potassium dichromate (K2Cr2O7) is __________ amu.

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Sulfur and fluorine react in a combination reaction to produce sulfur hexafluoride: S (s) + 3 F3 (g) → SF6 (g) The maximum amount of SF6 that can be produced from the reaction of 3.5 g of sulfur with 4.5 g of fluorine is __________ g.

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How many moles of magnesium oxide are produced by the reaction of 3.82 g of magnesium nitride with 7.73 g of water? Mg3N2 + 3 H2O → 2NH3 + 3MgO

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There are __________ molecules of methane in 0.123 mol of methane (CH4) .

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The combustion of propane (C3H8) produces CO2 and H2O: C3H8 (g) + 5 O2 (g) → 3CO2 (g) + 4 H2O (g) The reaction of 2.5 mol of O2 with 4.6 mol of C3H8 will produce __________ mol of H2O.

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Calcium carbide (CaC2) reacts with water to produce acetylene (C2H2) : CaC2 (s) + 2 H2O (g) → Ca(OH) 2 (s) + C2H2 (g) Production of 3.3 g of C2H2 requires consumption of __________ g of H2O.

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What is the mass % of carbon in dimethylsulfoxide (C2H6SO) rounded to three significant figures?

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Lithium and nitrogen react in a combination reaction to produce lithium nitride: 6Li (s) + N2 (g) → 2Li3N (s) How many moles of lithium are needed to produce 0.20 mol of Li3N when the reaction is carried out in the presence of excess nitrogen?

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Lead (II) carbonate decomposes to give lead (II) oxide and carbon dioxide: PbCO3 (s) → PbO (s) + CO2 (g) How many grams of lead (II) oxide will be produced by the decomposition of 2.50 g of lead (II) carbonate?

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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.

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When the following equation is balanced, the coefficient of HNO₃ is __________. HNO₃ (aq) + CaCO₃ (s) → Ca(NO₃) ₂ (aq) + CO₂ (g) + H₂O (l)

Correct Answer
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When the following equation is balanced, the coefficient of H₃PO₄ is __________. H₃PO₄ (aq) + NaOH (aq) → Na₃PO₄ (aq) + H₂O (l)

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The formula weight of potassium phosphate (K₃PO₄) is __________ amu.

Correct Answer
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Magnesium burns in air with a dazzling brilliance to produce magnesium oxide: 2Mg (s) + O₂ (g) → 2MgO (s) How many moles of O₂ are consumed when 4.11 mol of magnesium burns?

Correct Answer
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There are __________ mol of carbon atoms in 3 mol of dimethylsulfoxide (C₂H₆SO) .

Correct Answer
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Which of the following are combustion reactions? 1) CH₄ (g) + O₂ (g) → CO₂ (g) + H₂O (l) 2) CaO (s) + CO₂ (g) → CaCO₃ (s) 3) PbCO₃ (s) → PbO (s) + CO₂ (g) 4) CH₃OH (l) + O₂ (g) → CO₂ (g) + H₂O (l)

Correct Answer
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Predict the product in the combination reaction below. Al (s) + N₂ (g) → __________

Correct Answer
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The formula weight of potassium dichromate (K₂Cr₂O₇) is __________ amu.

Correct Answer
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Sulfur and fluorine react in a combination reaction to produce sulfur hexafluoride: S (s) + 3 F₃ (g) → SF₆ (g) The maximum amount of SF₆ that can be produced from the reaction of 3.5 g of sulfur with 4.5 g of fluorine is __________ g.

Correct Answer
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How many moles of magnesium oxide are produced by the reaction of 3.82 g of magnesium nitride with 7.73 g of water? Mg₃N₂ + 3 H₂O → 2NH₃ + 3MgO

Correct Answer
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There are __________ molecules of methane in 0.123 mol of methane (CH₄) .

Correct Answer
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The combustion of propane (C₃H₈) produces CO₂ and H₂O: C₃H₈ (g) + 5 O₂ (g) → 3CO₂ (g) + 4 H₂O (g) The reaction of 2.5 mol of O₂ with 4.6 mol of C₃H₈ will produce __________ mol of H₂O.

Correct Answer
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Calcium carbide (CaC₂) reacts with water to produce acetylene (C₂H₂) : CaC₂ (s) + 2 H₂O (g) → Ca(OH) ₂ (s) + C₂H₂ (g) Production of 3.3 g of C₂H₂ requires consumption of __________ g of H₂O.

Correct Answer
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What is the mass % of carbon in dimethylsulfoxide (C₂H₆SO) rounded to three significant figures?

Correct Answer
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Lithium and nitrogen react in a combination reaction to produce lithium nitride: 6Li (s) + N₂ (g) → 2Li₃N (s) How many moles of lithium are needed to produce 0.20 mol of Li₃N when the reaction is carried out in the presence of excess nitrogen?

Correct Answer
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Lead (II) carbonate decomposes to give lead (II) oxide and carbon dioxide: PbCO₃ (s) → PbO (s) + CO₂ (g) How many grams of lead (II) oxide will be produced by the decomposition of 2.50 g of lead (II) carbonate?

Correct Answer
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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 Answer
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