Question 1

The mass % of C in methane (CH4)is __________.

Accepted Answer

A) 25.13 
B) 133.6 
C) 74.87 
D) 92.26 
E) 7.743 
A) 25.13 
B) 133.6 
C) 74.87 
D) 92.26 
E) 7.743

Question 2

A compound contains 38.7% K, 13.9% N, and 47.4% O by mass. What is the empirical formula of the compound?

Accepted Answer

A) KNO3 
B) K2N2O3 
C) KNO2 
D) K2NO3 
E) K4NO5 
A) KNO3 
B) K2N2O3 
C) KNO2 
D) K2NO3 
E) K4NO5

Question 3

Calcium carbide (CaC2)reacts with water to produce acetylene (C2H2): CaC2 (s)+ 2 H2O (g)→ Ca(OH)2 (s)+ C2H2 (g)
Production of 13 g of C2H2 requires consumption of __________ g of H2O.

Accepted Answer

A) 4.5 
B) 9.0 
C) 18 
D) 4.8 × 102 
E) 4.8 × 10-2 
A) 4.5 
B) 9.0 
C) 18 
D) 4.8 × 102 
E) 4.8 × 10-2

Question 4

Sulfur and oxygen react to produce sulfur trioxide. In a particular experiment, 7.9 grams of SO3 are produced by the reaction of 5.0 grams of O2 with 6.0 grams of S. What is the % yield of SO3 in this experiment? S (s)+ O2 (g)→ SO3 (g)(not balanced)

Accepted Answer

A) 32 
B) 63 
C) 75 
D) 95 
E) 99 
A) 32 
B) 63 
C) 75 
D) 95 
E) 99

Question 5

When the following equation is balanced, the coefficient of Al is __________. Al (s)+ H2O (l)→ Al(OH)3 (s)+ H2 (g)

Accepted Answer

A) 1 
B) 2 
C) 3 
D) 5 
E) 4 
A) 1 
B) 2 
C) 3 
D) 5 
E) 4

Question 6

A sample of CH4O with a mass of 32.0 g contains __________ molecules of CH4O.

Accepted Answer

A) 5.32 × 10-23 
B) 1.00 
C) 1.88 × 1022 
D) 6.02 × 1023 
E) 32.0 
A) 5.32 × 10-23 
B) 1.00 
C) 1.88 × 1022 
D) 6.02 × 1023 
E) 32.0

Question 7

The mass % of H in methane (CH4)is __________.

Accepted Answer

A) 25.13 
B) 4.032 
C) 74.87 
D) 92.26 
E) 7.743 
A) 25.13 
B) 4.032 
C) 74.87 
D) 92.26 
E) 7.743

Question 8

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)+ 2 H2O (l)→ Mg(OH)2 (s)+ H2 (g)

Accepted Answer

A) 0.0962 
B) 0.0162 
C) 0.0485 
D) 0.219 
E) 0.204 
A) 0.0962 
B) 0.0162 
C) 0.0485 
D) 0.219 
E) 0.204

Question 9

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) 71.2 
A) 38.6 
B) 44.5 
C) 62.6 
D) 65.3 
E) 71.2

Question 10

Which hydrocarbon pair below have identical mass percentage of C?

Accepted Answer

A) C3H4 and C3H6 
B) C2H4 and C3H4 
C) C2H4 and C4H2 
D) C2H4 and C3H6 
E) none of the above 
A) C3H4 and C3H6 
B) C2H4 and C3H4 
C) C2H4 and C4H2 
D) C2H4 and C3H6 
E) none of the above

Question 11

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

Accepted Answer

Question 12

When the following equation is balanced, the coefficient of dinitrogen pentoxide is __________. N2O5 (g)+ H2O (l)→ HNO3 (aq)

Accepted Answer

A) 1 
B) 2 
C) 3 
D) 4 
E) 5 
A) 1 
B) 2 
C) 3 
D) 4 
E) 5

Question 13

When the following equation is balanced, the coefficient of C3H8O3 is __________. C3H8O3 (g)+ O2 (g)→ CO2 (g)+ H2O (g)

Accepted Answer

A) 1 
B) 2 
C) 3 
D) 7 
E) 5 
A) 1 
B) 2 
C) 3 
D) 7 
E) 5

Question 14

There are __________ hydrogen atoms in 25 molecules of C4H4S2.

Accepted Answer

A) 25 
B) 3.8 × 1024 
C) 6.0 × 1025 
D) 100 
E) 1.5 × 1025 
A) 25 
B) 3.8 × 1024 
C) 6.0 × 1025 
D) 100 
E) 1.5 × 1025

Question 15

A nitrogen oxide is 63.65% by mass nitrogen. The molecular formula could be __________.

Accepted Answer

A) NO 
B) NO2 
C) N2O 
D) N2O4 
E) either NO2 or N2O4 
A) NO 
B) NO2 
C) N2O 
D) N2O4 
E) either NO2 or N2O4

Question 16

What is the maximum mass in grams of NH3 that can be produced by the reaction of 1.0 g of N2 with 3.0 g of H2 via the equation below? N2 (g)+ H2 (g)→ NH3 (g)(not balanced)

Accepted Answer

A) 2.0 
B) 1.2 
C) 0.61 
D) 17 
E) 4.0 
A) 2.0 
B) 1.2 
C) 0.61 
D) 17 
E) 4.0

Question 17

Under appropriate conditions, nitrogen and hydrogen undergo a combination reaction to yield ammonia: N2 (g)+ 3 H2 (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) 2.32 
A) 0.166 
B) 1.00 
C) 1.5 
D) 1.71 
E) 2.32

Question 18

Calculate the percentage by mass of hydrogen in PtCl2(N H3)2

Accepted Answer

A) 1.558 
B) 1.008 
C) 0.672 
D) 0.034 
E) 2.016 
A) 1.558 
B) 1.008 
C) 0.672 
D) 0.034 
E) 2.016

Question 19

A 3.92-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) 0.0529 
E) 0.0264 
A) 2.32 
B) 1.65 
C) 0.111 
D) 0.0529 
E) 0.0264

Question 20

The combustion of ammonia in the presence of excess oxygen yields NO2 and H2O: 4 NH3 (g)+ 7 O2 (g)→ 4 NO2 (g)+ 6 H2O (g)
The combustion of 43.9 g of ammonia produces __________ g of NO2.

Accepted Answer

A) 2.58 
B) 178 
C) 119 
D) 0.954 
E) 43.9 
A) 2.58 
B) 178 
C) 119 
D) 0.954 
E) 43.9

Exam 3: Stoichiometry: Calculations With Chemical Formulas and Equations

The mass % of C in methane (CH4)is __________.

A compound contains 38.7% K, 13.9% N, and 47.4% O by mass. What is the empirical formula of the compound?

Calcium carbide (CaC2)reacts with water to produce acetylene (C2H2): CaC2 (s)+ 2 H2O (g)→ Ca(OH)2 (s)+ C2H2 (g) Production of 13 g of C2H2 requires consumption of __________ g of H2O.

Sulfur and oxygen react to produce sulfur trioxide. In a particular experiment, 7.9 grams of SO3 are produced by the reaction of 5.0 grams of O2 with 6.0 grams of S. What is the % yield of SO3 in this experiment? S (s)+ O2 (g)→ SO3 (g)(not balanced)

When the following equation is balanced, the coefficient of Al is __________. Al (s)+ H2O (l)→ Al(OH)3 (s)+ H2 (g)

A sample of CH4O with a mass of 32.0 g contains __________ molecules of CH4O.

The mass % of H in methane (CH4)is __________.

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)+ 2 H2O (l)→ Mg(OH)2 (s)+ H2 (g)

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

Which hydrocarbon pair below have identical mass percentage of C?

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

When the following equation is balanced, the coefficient of dinitrogen pentoxide is __________. N2O5 (g)+ H2O (l)→ HNO3 (aq)

When the following equation is balanced, the coefficient of C3H8O3 is __________. C3H8O3 (g)+ O2 (g)→ CO2 (g)+ H2O (g)

There are __________ hydrogen atoms in 25 molecules of C4H4S2.

A nitrogen oxide is 63.65% by mass nitrogen. The molecular formula could be __________.

What is the maximum mass in grams of NH3 that can be produced by the reaction of 1.0 g of N2 with 3.0 g of H2 via the equation below? N2 (g)+ H2 (g)→ NH3 (g)(not balanced)

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

Calculate the percentage by mass of hydrogen in PtCl2(N H3)2

A 3.92-g sample of magnesium nitrate, Mg(NO3)2, contains __________ mol of this compound.

The combustion of ammonia in the presence of excess oxygen yields NO2 and H2O: 4 NH3 (g)+ 7 O2 (g)→ 4 NO2 (g)+ 6 H2O (g) The combustion of 43.9 g of ammonia produces __________ g of NO2.

Introduction: Matter and Measurement

Atoms, Molecules, and Ions

Aqueous Reactions and Solution Stoichiometry

Thermochemistry

Electronic Structure of Atoms

Periodic Properties of the Elements

Basic Concepts of Chemical Bonding

Molecular Geometry and Bonding Theories

Gases

Liquids and Intermolecular Forces

Solids and Modern Materials

Properties of Solutions

Chemical Kinetics

Chemical Equilibrium

Acid-Base Equilibria

Additional Aspects of Aqueous Equilibria

Chemistry of the Environment

Chemical Thermodynamics

Electrochemistry

Nuclear Chemistry

Chemistry of the Nonmetals

Transition Metals and Coordination Chemistry

The Chemistry of Life: Organic and Biological Chemistry

Filters

The mass % of C in methane (CH₄)is __________.

Calcium carbide (CaC₂)reacts with water to produce acetylene (C₂H₂): CaC₂ (s)+ 2 H₂O (g)→ Ca(OH)₂ (s)+ C₂H₂ (g) Production of 13 g of C₂H₂ requires consumption of __________ g of H₂O.

Sulfur and oxygen react to produce sulfur trioxide. In a particular experiment, 7.9 grams of SO₃ are produced by the reaction of 5.0 grams of O₂ with 6.0 grams of S. What is the % yield of SO₃ in this experiment? S (s)+ O₂ (g)→ SO₃ (g)(not balanced)

When the following equation is balanced, the coefficient of Al is __________. Al (s)+ H₂O (l)→ Al(OH)₃ (s)+ H₂ (g)

A sample of CH₄O with a mass of 32.0 g contains __________ molecules of CH₄O.

The mass % of H in methane (CH₄)is __________.

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)+ 2 H₂O (l)→ Mg(OH)₂ (s)+ H₂ (g)

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

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

When the following equation is balanced, the coefficient of dinitrogen pentoxide is __________. N₂O₅ (g)+ H₂O (l)→ HNO₃ (aq)

When the following equation is balanced, the coefficient of C₃H₈O₃ is __________. C₃H₈O₃ (g)+ O₂ (g)→ CO₂ (g)+ H₂O (g)

There are __________ hydrogen atoms in 25 molecules of C₄H₄S₂.

What is the maximum mass in grams of NH3 that can be produced by the reaction of 1.0 g of N₂ with 3.0 g of H₂ via the equation below? N₂ (g)+ H₂ (g)→ NH₃ (g)(not balanced)

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

Calculate the percentage by mass of hydrogen in PtCl₂(N H₃)₂

A 3.92-g sample of magnesium nitrate, Mg(NO₃)₂, contains __________ mol of this compound.

The combustion of ammonia in the presence of excess oxygen yields NO₂ and H₂O: 4 NH₃ (g)+ 7 O₂ (g)→ 4 NO₂ (g)+ 6 H₂O (g) The combustion of 43.9 g of ammonia produces __________ g of NO₂.