Question 1

What is one of the advantages of a fuel cell?

Accepted Answer

A) They can run for a very long time as long as you keep adding fuel. 
B) They are more efficient than combustion. 
C) They have lower emission of pollutants than combustion. 
D) all of the above 
E) only A and B 
A) They can run for a very long time as long as you keep adding fuel. 
B) They are more efficient than combustion. 
C) They have lower emission of pollutants than combustion. 
D) all of the above 
E) only A and B

Question 2

What is the purpose of a salt-bridge?

Accepted Answer

A) to allow ions to migrate between solutions 
B) to allow people to cross over salt water 
C) to allow electrons to migrate through solutions 
D) to allow salt to form in the oxidation-reduction reactions 
E) none of the above 
A) to allow ions to migrate between solutions 
B) to allow people to cross over salt water 
C) to allow electrons to migrate through solutions 
D) to allow salt to form in the oxidation-reduction reactions 
E) none of the above

Question 3

A major source of chlorine gas, $\mathrm { Cl } _ { 2 }$ ,is from the electrolysis of brine,which is concentrated salt water, $\mathrm { NaCl } ( \mathrm { aq } )$ What is the sign of the electrode where the chlorine gas is formed? Is it negative or positive?

Accepted Answer

A) Positive,since the chloride ions lose electrons to form chlorine molecules. 
B) Negative,since the chlorine gas needs to deposit electrons to form chloride ions. 
C) Neither,since chlorine gas is a neutral molecule,there is not electrode attraction. 
D) Both,since the chloride ions from NaCl (aq)are attracted to the positive electrode to form chlorine molecules while the produced chlorine gas molecules move to deposit electrons at the negative electrode. 
A) Positive,since the chloride ions lose electrons to form chlorine molecules. 
B) Negative,since the chlorine gas needs to deposit electrons to form chloride ions. 
C) Neither,since chlorine gas is a neutral molecule,there is not electrode attraction. 
D) Both,since the chloride ions from NaCl (aq)are attracted to the positive electrode to form chlorine molecules while the produced chlorine gas molecules move to deposit electrons at the negative electrode.

Question 4

How many electrons are gained or lost in the following half-reaction? 2 Na → 2 Na+

Accepted Answer

A) 2 electrons are lost 
B) 1/2 electron is gained 
C) 1/2 electron is lost 
D) 2 electrons are gained 
E) 4 electrons are gained 
A) 2 electrons are lost 
B) 1/2 electron is gained 
C) 1/2 electron is lost 
D) 2 electrons are gained 
E) 4 electrons are gained

Question 5

When the hydronium ion concentration equals 1 mole per liter,what is the pH of the solution? Is the solution acidic or basic?

Accepted Answer

A) pH = 0,this is an acidic solution. 
B) pH = 1,this is an acidic solution. 
C) pH = 10,this is a basic solution. 
D) pH = 7,this is a neutral solution. 
A) pH = 0,this is an acidic solution. 
B) pH = 1,this is an acidic solution. 
C) pH = 10,this is a basic solution. 
D) pH = 7,this is a neutral solution.

Question 6

What is the main characteristic of a strong acid?

Accepted Answer

A) It is completely dissociated in water. 
B) It readily gives up its proton to a base. 
C) It is corrosive. 
D) It will damage your skin. 
E) all of the above 
A) It is completely dissociated in water. 
B) It readily gives up its proton to a base. 
C) It is corrosive. 
D) It will damage your skin. 
E) all of the above

Question 7

Which of the following materials is most likely to act as an oxidizing agent?

Accepted Answer

A) Na 
B) Na+ 
C) Cl2 
D) Cl- 
E) both A and B 
A) Na 
B) Na+ 
C) Cl2 
D) Cl- 
E) both A and B

Question 8

Qualitatively,what happens to the hydroxide ion concentration if you decrease the hydronium ion concentration?

Accepted Answer

A) The concentration of OH- stays the same but the ratio OH-/H3O+ changes. 
B) The concentration of OH- increases but the ratio stays the same. 
C) The concentration of OH- increases. 
D) none of the above 
A) The concentration of OH- stays the same but the ratio OH-/H3O+ changes. 
B) The concentration of OH- increases but the ratio stays the same. 
C) The concentration of OH- increases. 
D) none of the above

Question 9

Why is oxygen usually an oxidizing agent?

Accepted Answer

A) It is a very electronegative element. 
B) It does not undergo reduction. 
C) It likes to be oxidized. 
D) It is very abundant and so it is easier to react than nitrogen. 
E) all of the above 
A) It is a very electronegative element. 
B) It does not undergo reduction. 
C) It likes to be oxidized. 
D) It is very abundant and so it is easier to react than nitrogen. 
E) all of the above

Question 10

Which of the following statements best describes an anode?

Accepted Answer

A) the negatively charged electrode of a battery or electrochemical apparatus 
B) the place where oxidation is taking place in a battery or electrochemical apparatus 
C) the place from which electrons are flowing away from 
D) all of the above 
E) none of the above 
A) the negatively charged electrode of a battery or electrochemical apparatus 
B) the place where oxidation is taking place in a battery or electrochemical apparatus 
C) the place from which electrons are flowing away from 
D) all of the above 
E) none of the above

Question 11

If the pH of a solution was 7 and you were to increase the hydronium ion concentration 1000x,what would the pH be?

Accepted Answer

A) 4 
B) 4 M 
C) 1 × 10-4 M 
D) 7000 M 
E) 10 
A) 4 
B) 4 M 
C) 1 × 10-4 M 
D) 7000 M 
E) 10

Question 12

Arrange the following images of an aqueous base solution in order of increasing base strength:

Accepted Answer

A) A,B,C 
B) B,C,A 
C) C,B,A 
D) A,C,B 
E) All are equally strong. 
A) A,B,C 
B) B,C,A 
C) C,B,A 
D) A,C,B 
E) All are equally strong.

Question 13

What is a reduction?

Accepted Answer

A) the gain of electrons 
B) the reduction of the number of electrons 
C) the loss of an electron from the valence shell 
D) the reaction of oxygen with a reductant 
E) the formation of red compounds in the presence of an oxidant 
A) the gain of electrons 
B) the reduction of the number of electrons 
C) the loss of an electron from the valence shell 
D) the reaction of oxygen with a reductant 
E) the formation of red compounds in the presence of an oxidant

Question 14

When a hydronium ion concentration equals 1 × $10 ^ { - 10 }$ moles per liter,what is the pH of the solution? Is the solution acidic or basic?

Accepted Answer

A) The pH of this solution is 4,which is acidic. 
B) The pH of this solution is 8,which is basic. 
C) The pH of this solution is 6,which is acidic. 
D) The pH of this solution is 10,which is basic. 
A) The pH of this solution is 4,which is acidic. 
B) The pH of this solution is 8,which is basic. 
C) The pH of this solution is 6,which is acidic. 
D) The pH of this solution is 10,which is basic.

Question 15

Why might a small piece of chalk made of calcium carbonate be useful for alleviating acid indigestion?

Accepted Answer

A) Calcium carbonate is a base that reacts to neutralize any excess acids. 
B) Calcium carbonate is able to absorb excess acid and carry it out of the system. 
C) Calcium carbonate is able to add an extra lining to the stomach to protect it from the excess acid. 
D) Calcium carbonate is able to turn the acid into a gas which can relieve the build up of excess acid. 
A) Calcium carbonate is a base that reacts to neutralize any excess acids. 
B) Calcium carbonate is able to absorb excess acid and carry it out of the system. 
C) Calcium carbonate is able to add an extra lining to the stomach to protect it from the excess acid. 
D) Calcium carbonate is able to turn the acid into a gas which can relieve the build up of excess acid.

Question 16

What might the relationship be between an element's electronegativity and its ability to behave as an oxidizing agent?

Accepted Answer

A) As the electronegativity goes up the ability of an element to act as an oxidant increases. 
B) As the electronegativity goes up the ability of an element to act as an oxidant decreases. 
C) As the electronegativity goes up the ability of an element to act as an oxidant stays the same. 
D) As the electronegativity increases the element has a tendency to undergo oxidation. 
E) none of the above 
A) As the electronegativity goes up the ability of an element to act as an oxidant increases. 
B) As the electronegativity goes up the ability of an element to act as an oxidant decreases. 
C) As the electronegativity goes up the ability of an element to act as an oxidant stays the same. 
D) As the electronegativity increases the element has a tendency to undergo oxidation. 
E) none of the above

Question 17

Which of the following solutions is the most acidic?

Accepted Answer

A) a solution with a pH = 14 
B) a solution with a pH = 10 
C) a solution with a pH = 7 
D) a solution with a pH = 4 
E) All of the solutions are basic. 
A) a solution with a pH = 14 
B) a solution with a pH = 10 
C) a solution with a pH = 7 
D) a solution with a pH = 4 
E) All of the solutions are basic.

Question 18

Why is carbon dioxide able to be stored more effectively in ocean water vs.fresh water?

Accepted Answer

A) The pH of the ocean is pretty high and so the carbon dioxide is trapped in a neutralization reaction. 
B) The oceans are large and so you can dissolve more CO2 in them. 
C) Gases are more soluble in cold water than warm water and the oceans are colder than fresh water lakes so you can dissolve more CO2 in them. 
D) The pH of the ocean is very low and so the carbon dioxide is trapped as an acid because like dissolves like. 
E) none of the above 
A) The pH of the ocean is pretty high and so the carbon dioxide is trapped in a neutralization reaction. 
B) The oceans are large and so you can dissolve more CO2 in them. 
C) Gases are more soluble in cold water than warm water and the oceans are colder than fresh water lakes so you can dissolve more CO2 in them. 
D) The pH of the ocean is very low and so the carbon dioxide is trapped as an acid because like dissolves like. 
E) none of the above

Question 19

Which of the half-reactions below would be complementary,balance the following half-reaction,and be chemically reasonable? Br2 → 2 Br-

Accepted Answer

A) 2 K → 2 K+ 
B) K+ → K 
C) K → K+ 
D) 2 K+ → 2 K 
E) K → K+2 
A) 2 K → 2 K+ 
B) K+ → K 
C) K → K+ 
D) 2 K+ → 2 K 
E) K → K+2

Question 20

A major source of chlorine gas, $\mathrm { Cl } _ { 2 }$ ,is from the electrolysis of brine,which is concentrated salt water, $\mathrm { NaCl } ( \mathrm { aq } )$ Which of the following is the balanced chemical reaction for this electrolysis reaction?

Accepted Answer

A) NaCl (aq)+ H2O ? NaOH (aq)+ $\mathrm { Cl } _ { 2 }$ (g)+ $\mathrm { H } _ { 2 }$ (g) 
B) 2 NaCl (aq)+ $\mathrm { H } _ { 2 }$ O ? $\mathrm { Na } _ { 2 }$ O (aq)+ 2 HCl (aq) 
C) 2 NaCl (aq)+ 2 $\mathrm { H } _ { 2 }$ O ? 2 Na (s)+ O2 (g)+ 2 $\mathrm { H } _ { 2 }$ (g)+ $\mathrm { Cl } _ { 2 }$ (g) 
D) 2 NaCl (aq)+ $\mathrm { H } _ { 2 }$ O ? 2 NaH (aq)+ $\mathrm { Cl } _ { 2 }$ 
A) NaCl (aq)+ H2O ? NaOH (aq)+ $\mathrm { Cl } _ { 2 }$ (g)+ $\mathrm { H } _ { 2 }$ (g) 
B) 2 NaCl (aq)+ $\mathrm { H } _ { 2 }$ O ? $\mathrm { Na } _ { 2 }$ O (aq)+ 2 HCl (aq) 
C) 2 NaCl (aq)+ 2 $\mathrm { H } _ { 2 }$ O ? 2 Na (s)+ O2 (g)+ 2 $\mathrm { H } _ { 2 }$ (g)+ $\mathrm { Cl } _ { 2 }$ (g) 
D) 2 NaCl (aq)+ $\mathrm { H } _ { 2 }$ O ? 2 NaH (aq)+ $\mathrm { Cl } _ { 2 }$

Exam 18: Two Classes of Chemical Reactions

What is one of the advantages of a fuel cell?

What is the purpose of a salt-bridge?

A major source of chlorine gas, Cl2\mathrm { Cl } _ { 2 }Cl2​ ,is from the electrolysis of brine,which is concentrated salt water, NaCl(aq)\mathrm { NaCl } ( \mathrm { aq } )NaCl(aq) What is the sign of the electrode where the chlorine gas is formed? Is it negative or positive?

How many electrons are gained or lost in the following half-reaction? 2 Na → 2 Na+

When the hydronium ion concentration equals 1 mole per liter,what is the pH of the solution? Is the solution acidic or basic?

What is the main characteristic of a strong acid?

Which of the following materials is most likely to act as an oxidizing agent?

Qualitatively,what happens to the hydroxide ion concentration if you decrease the hydronium ion concentration?

Why is oxygen usually an oxidizing agent?

Which of the following statements best describes an anode?

If the pH of a solution was 7 and you were to increase the hydronium ion concentration 1000x,what would the pH be?

Arrange the following images of an aqueous base solution in order of increasing base strength:

What is a reduction?

When a hydronium ion concentration equals 1 × 10−1010 ^ { - 10 }10−10 moles per liter,what is the pH of the solution? Is the solution acidic or basic?

Why might a small piece of chalk made of calcium carbonate be useful for alleviating acid indigestion?

What might the relationship be between an element's electronegativity and its ability to behave as an oxidizing agent?

Which of the following solutions is the most acidic?

Why is carbon dioxide able to be stored more effectively in ocean water vs.fresh water?

Which of the half-reactions below would be complementary,balance the following half-reaction,and be chemically reasonable? Br2 → 2 Br-

A major source of chlorine gas, Cl2\mathrm { Cl } _ { 2 }Cl2​ ,is from the electrolysis of brine,which is concentrated salt water, NaCl(aq)\mathrm { NaCl } ( \mathrm { aq } )NaCl(aq) Which of the following is the balanced chemical reaction for this electrolysis reaction?

Patterns of Motion and Equilibrium

Newtons Laws of Motion

Momentum and Energy

Gravity, Projectiles, and Satellites

Fluid Mechanics

Thermal Energy and Thermodynamics

Heat Transfer and Change of Phase

Static and Current Electricity

Magnetism and Electromagnetic Induction

Waves and Sound

Light

Atoms and the Periodic Table

The Atomic Nucleus and Radioactivity

Elements of Chemistry

How Atoms Bond and Molecules Attract

Mixtures

How Chemicals React

Organic Compounds

Rocks and Minerals

Plate Tectonics and Earths Interior

Shaping Earths Surface

Geologic Time - Reading the Rock Record

The Oceans, Atmosphere, and Climatic Effects

Driving Forces of Weather

The Solar System

Stars and Galaxies

The Structure of Space and Time

Prologue: The Nature of Science

Filters

A major source of chlorine gas, $\mathrm { Cl } _ { 2 }$ ,is from the electrolysis of brine,which is concentrated salt water, $\mathrm { NaCl } ( \mathrm { aq } )$ What is the sign of the electrode where the chlorine gas is formed? Is it negative or positive?

How many electrons are gained or lost in the following half-reaction? 2 Na → 2 Na⁺

When a hydronium ion concentration equals 1 × $10 ^ { - 10 }$ moles per liter,what is the pH of the solution? Is the solution acidic or basic?

Which of the half-reactions below would be complementary,balance the following half-reaction,and be chemically reasonable? Br₂ → 2 Br^-

A major source of chlorine gas, $\mathrm { Cl } _ { 2 }$ ,is from the electrolysis of brine,which is concentrated salt water, $\mathrm { NaCl } ( \mathrm { aq } )$ Which of the following is the balanced chemical reaction for this electrolysis reaction?