Question 1

What happens to the pH of soda water as it loses its carbonation?

Accepted Answer

A) It does not change since the carbonation has nothing to do with pH. 
B) It decreases as it loses the carbon dioxide molecules which form the carbonic acid in the soda. 
C) It increases as it loses the carbon dioxide molecules which form the carbonic acid in the soda. 
D) It decreases as the soda becomes more concentrated through the loss of the carbon dioxide gases. 
A) It does not change since the carbonation has nothing to do with pH. 
B) It decreases as it loses the carbon dioxide molecules which form the carbonic acid in the soda. 
C) It increases as it loses the carbon dioxide molecules which form the carbonic acid in the soda. 
D) It decreases as the soda becomes more concentrated through the loss of the carbon dioxide gases.

Question 2

What is a base?

Accepted Answer

A) anything that accepts a hydrogen ion 
B) anything that accepts a hydroxide ion 
C) anything that donates a hydroxide ion 
D) anything that can be used to clean drains 
E) anything with a bitter taste 
A) anything that accepts a hydrogen ion 
B) anything that accepts a hydroxide ion 
C) anything that donates a hydroxide ion 
D) anything that can be used to clean drains 
E) anything with a bitter taste

Question 3

For the following acid-base reaction,identify what is formed in the space marked. H2SO4 + KOH ⇌ KHSO4 + ???

Accepted Answer

A) K2SO4 
B) H3OSO4 
C) H2O 
D) KOH2SO4 
E) none of the above 
A) K2SO4 
B) H3OSO4 
C) H2O 
D) KOH2SO4 
E) none of the above

Question 4

Which of the following materials is most likely to act as a reducing 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 5

How many electrons are transferred from iron atoms to oxygen atoms in the formation of two molecules of iron hydroxide,Fe $( \mathrm { OH } ) _ { 2 }$ ?

Accepted Answer

A) 4 electrons 
B) 8 electrons 
C) 16 electrons 
D) 12 electrons 
A) 4 electrons 
B) 8 electrons 
C) 16 electrons 
D) 12 electrons

Question 6

As the pH increases,the hydroxide ion concentration

Accepted Answer

A) goes down. 
B) gets larger. 
C) starts to affect the H+ concentration. 
D) starts to decrease because it is reacting with the excess hydronium ions. 
E) stays constant. 
A) goes down. 
B) gets larger. 
C) starts to affect the H+ concentration. 
D) starts to decrease because it is reacting with the excess hydronium ions. 
E) stays constant.

Question 7

If the pH of a solution is 10,what is the hydroxide ion concentration?

Accepted Answer

A) 1 × 10-4 M 
B) 4 M 
C) 14 M 
D) -14 M 
E) -1 × 1014 M 
A) 1 × 10-4 M 
B) 4 M 
C) 14 M 
D) -14 M 
E) -1 × 1014 M

Question 8

If the pH of a solution was 7 and you were to increase the hydroxide ion concentration 100x,what would the pH be?

Accepted Answer

A) 9 
B) 5 M 
C) 1 × 10-5 M 
D) 700 M 
E) 5 
A) 9 
B) 5 M 
C) 1 × 10-5 M 
D) 700 M 
E) 5

Question 9

In the oxidation-reduction reaction Mg(s)+ $\mathrm { Cu } ^ { 2 + }$ (aq)? 3 $\mathrm { Mg } ^ { 2 + }$ (aq)+ Cu(s),which atom or ion is reduced? Which atom or ion is oxidized?

Accepted Answer

A) The $\mathrm { Cu } ^ { 2 + }$ ion is oxidized as it gains electrons from the copper metal,Cu.The magnesium metal,Mg,is reduced as it loses electrons to form $\mathrm { Mg } ^ { 2 + }$ . 
B) The $\mathrm { Mg } ^ { 2 + }$ ion is reduced as it gains electrons from the copper metal,Cu.The $\mathrm { Cu } ^ { 2 + }$ is oxidized as it loses electrons to the $\mathrm { Mg } ^ { 2 + }$ . 
C) The $\mathrm { Cu } ^ { 2 + }$ ion is reduced as it gains electrons to form copper metal,Cu.The magnesium metal,Mg,is oxidized as it loses electrons to form $\mathrm { Mg } ^ { 2 + }$ . 
D) Since Mg goes from a solid to an aqueous solution and Cu goes from an aqueous solution to a solid,an oxidation-reduction reaction did not occur. 
A) The $\mathrm { Cu } ^ { 2 + }$ ion is oxidized as it gains electrons from the copper metal,Cu.The magnesium metal,Mg,is reduced as it loses electrons to form $\mathrm { Mg } ^ { 2 + }$ . 
B) The $\mathrm { Mg } ^ { 2 + }$ ion is reduced as it gains electrons from the copper metal,Cu.The $\mathrm { Cu } ^ { 2 + }$ is oxidized as it loses electrons to the $\mathrm { Mg } ^ { 2 + }$ . 
C) The $\mathrm { Cu } ^ { 2 + }$ ion is reduced as it gains electrons to form copper metal,Cu.The magnesium metal,Mg,is oxidized as it loses electrons to form $\mathrm { Mg } ^ { 2 + }$ . 
D) Since Mg goes from a solid to an aqueous solution and Cu goes from an aqueous solution to a solid,an oxidation-reduction reaction did not occur.

Question 10

Upon combustion,about how many grams of water vapor are produced from every 16 grams of methane, $\mathrm { CH } _ { 4 }$ ? $\mathrm { CH } _ { 4 }$ + 2 $\mathrm { O } _ { 2 }$ ? $\mathrm { CO } _ { 2 }$ + 2 $\mathrm { H } _ { 2 }$ O

Accepted Answer

A) 16 grams 
B) 18 grams 
C) 36 grams 
D) 8 grams 
A) 16 grams 
B) 18 grams 
C) 36 grams 
D) 8 grams

Question 11

Why are combustion reactions generally exothermic?

Accepted Answer

A) Hydrogen easily pulls electrons from the oxygen in water molecules and are reduced. 
B) During combustion oxygen is oxidized,which gives off lots of energy. 
C) Combustion involves the transfer of electrons to oxygen,which has an extremely high tendency for gaining electrons. 
D) It is highly exothermic because combustion involves an oxidation-reduction reaction between a metallic material and oxygen. 
A) Hydrogen easily pulls electrons from the oxygen in water molecules and are reduced. 
B) During combustion oxygen is oxidized,which gives off lots of energy. 
C) Combustion involves the transfer of electrons to oxygen,which has an extremely high tendency for gaining electrons. 
D) It is highly exothermic because combustion involves an oxidation-reduction reaction between a metallic material and oxygen.

Question 12

In a battery,the following oxidation-reduction reactions are taking place: Mn2O3 + ZnO → 2 MnO2 + Zn
What is being formed at the cathode?

Accepted Answer

A) Zn 
B) ZnO 
C) MnO2 
D) Mn2O3 
E) none of the above 
A) Zn 
B) ZnO 
C) MnO2 
D) Mn2O3 
E) none of the above

Question 13

The general chemical equation for photosynthesis is shown below.Through this reaction is the carbon oxidized or reduced? How can you tell? 6 $\mathrm { CO } _ { 2 }$ + 6 $\mathrm { H } _ { 2 }$ O ? $\mathrm { C } _ { 6 } \mathrm { H } _ { 12 } \mathrm { O } _ { 6 }$ + 6 $\mathrm { O } _ { 2 }$

Accepted Answer

A) Oxidized,since carbon is in the +4 oxidation state in $\mathrm { CO } _ { 2 }$ but in the +6 oxidation state in the product, $\mathrm { C } _ { 6 } \mathrm { H } _ { 12 } \mathrm { O } _ { 6 }$ ,glucose. 
B) Reduced,since in carbon dioxide there are two oxygen atoms for every one carbon but within the product, $\mathrm { C } _ { 6 } \mathrm { H } _ { 12 } \mathrm { O } _ { 6 }$ ,(glucose),there is only one oxygen for every one carbon. 
C) Neither,since carbon does not change its oxidation state and is neither oxidized nor reduced. 
D) Both,since the carbon atoms within the glucose molecules display two different charge states. 
A) Oxidized,since carbon is in the +4 oxidation state in $\mathrm { CO } _ { 2 }$ but in the +6 oxidation state in the product, $\mathrm { C } _ { 6 } \mathrm { H } _ { 12 } \mathrm { O } _ { 6 }$ ,glucose. 
B) Reduced,since in carbon dioxide there are two oxygen atoms for every one carbon but within the product, $\mathrm { C } _ { 6 } \mathrm { H } _ { 12 } \mathrm { O } _ { 6 }$ ,(glucose),there is only one oxygen for every one carbon. 
C) Neither,since carbon does not change its oxidation state and is neither oxidized nor reduced. 
D) Both,since the carbon atoms within the glucose molecules display two different charge states.

Question 14

In one type of fuel cell,the following oxidation-reduction reactions are taking place: 2 H2 + O2 → 2 H2O
What is the oxidant?

Accepted Answer

A) H2 
B) O2 
C) H2O 
D) all of the above 
E) none of the above 
A) H2 
B) O2 
C) H2O 
D) all of the above 
E) none of the above

Question 15

Which of the following species is undergoing oxidation? 2 CuBr → 2Cu + Br2

Accepted Answer

A) Cu 
B) CuBr 
C) Cu+ 
D) Br- 
E) Br2 
A) Cu 
B) CuBr 
C) Cu+ 
D) Br- 
E) Br2

Question 16

How might electrolysis be used to raise the hull of a sunken ship?

Accepted Answer

A) An electric current passed through the hull of the ship would produce electrolysis and the gases trapped in the compartments of the vessel would push it upwards. 
B) The electrolysis of the water beneath the hull of the ship would boil the water and create upward pressure,thus buoying the ship upward. 
C) The gaseous products of the electrolysis of water could be collected with large bags attached to the hull of the ship.As the bags inflate with the gas they are buoyed upward pulling the ship also upward. 
D) Electrolysis could only be used to raise the hull of a ship if the ship were made of iron.If so,the electrolysis of the iron metal might produce enough gas to lift the ship. 
A) An electric current passed through the hull of the ship would produce electrolysis and the gases trapped in the compartments of the vessel would push it upwards. 
B) The electrolysis of the water beneath the hull of the ship would boil the water and create upward pressure,thus buoying the ship upward. 
C) The gaseous products of the electrolysis of water could be collected with large bags attached to the hull of the ship.As the bags inflate with the gas they are buoyed upward pulling the ship also upward. 
D) Electrolysis could only be used to raise the hull of a ship if the ship were made of iron.If so,the electrolysis of the iron metal might produce enough gas to lift the ship.

Question 17

In a battery,the following oxidation-reduction reactions are taking place: Mn2O3 + ZnO → 2 MnO2 + Zn
What is undergoing an oxidation as written?

Accepted Answer

A) Zn 
B) ZnO 
C) MnO2 
D) Mn2O3 
E) none of the above 
A) Zn 
B) ZnO 
C) MnO2 
D) Mn2O3 
E) none of the above

Question 18

In a battery,the following two oxidation-reduction reactions are taking place: rxn A: Zn + 2 OH- → ZnO + H2O + 2e-
Rxn B: 2 MnO2 + H2O + 2e- → Mn2O3 + 2 OH-
What is undergoing oxidation?

Accepted Answer

A) Zn 
B) ZnO 
C) MnO2 
D) H2O 
E) OH- 
A) Zn 
B) ZnO 
C) MnO2 
D) H2O 
E) OH-

Question 19

According to the following reaction,which molecule is acting as an acid? OH- + NH4+ → H2O + NH3

Accepted Answer

A) H2O 
B) NH3 
C) OH- 
D) NH4+ 
E) none of the above 
A) H2O 
B) NH3 
C) OH- 
D) NH4+ 
E) none of the above

Question 20

Why is the formation of iron hydroxide,Fe $( \mathrm { OH } ) _ { 2 }$ ,from $\mathrm { Fe } ^ { 2 + }$ and O $\mathrm { H } ^ { - }$ not considered an oxidation-reduction reaction?

Accepted Answer

A) The iron is only oxidized and nothing is reduced. 
B) The iron is only reduced,not oxidized. 
C) The $\mathrm { Fe } ^ { 2 + }$ ion is not changed during this chemical reaction. 
D) Iron can never be oxidized or reduced. 
A) The iron is only oxidized and nothing is reduced. 
B) The iron is only reduced,not oxidized. 
C) The $\mathrm { Fe } ^ { 2 + }$ ion is not changed during this chemical reaction. 
D) Iron can never be oxidized or reduced.

Exam 18: Two Classes of Chemical Reactions

What happens to the pH of soda water as it loses its carbonation?

What is a base?

For the following acid-base reaction,identify what is formed in the space marked. H2SO4 + KOH ⇌ KHSO4 + ???

Which of the following materials is most likely to act as a reducing agent?

How many electrons are transferred from iron atoms to oxygen atoms in the formation of two molecules of iron hydroxide,Fe (OH)2( \mathrm { OH } ) _ { 2 }(OH)2​ ?

As the pH increases,the hydroxide ion concentration

If the pH of a solution is 10,what is the hydroxide ion concentration?

If the pH of a solution was 7 and you were to increase the hydroxide ion concentration 100x,what would the pH be?

In the oxidation-reduction reaction Mg(s)+ Cu2+\mathrm { Cu } ^ { 2 + }Cu2+ (aq)? 3 Mg2+\mathrm { Mg } ^ { 2 + }Mg2+ (aq)+ Cu(s),which atom or ion is reduced? Which atom or ion is oxidized?

Upon combustion,about how many grams of water vapor are produced from every 16 grams of methane, CH4\mathrm { CH } _ { 4 }CH4​ ? CH4\mathrm { CH } _ { 4 }CH4​ + 2 O2\mathrm { O } _ { 2 }O2​ ? CO2\mathrm { CO } _ { 2 }CO2​ + 2 H2\mathrm { H } _ { 2 }H2​ O

Why are combustion reactions generally exothermic?

In a battery,the following oxidation-reduction reactions are taking place: Mn2O3 + ZnO → 2 MnO2 + Zn What is being formed at the cathode?

In one type of fuel cell,the following oxidation-reduction reactions are taking place: 2 H2 + O2 → 2 H2O What is the oxidant?

Which of the following species is undergoing oxidation? 2 CuBr → 2Cu + Br2

How might electrolysis be used to raise the hull of a sunken ship?

In a battery,the following oxidation-reduction reactions are taking place: Mn2O3 + ZnO → 2 MnO2 + Zn What is undergoing an oxidation as written?

In a battery,the following two oxidation-reduction reactions are taking place: rxn A: Zn + 2 OH- → ZnO + H2O + 2e- Rxn B: 2 MnO2 + H2O + 2e- → Mn2O3 + 2 OH- What is undergoing oxidation?

According to the following reaction,which molecule is acting as an acid? OH- + NH4+ → H2O + NH3

Why is the formation of iron hydroxide,Fe (OH)2( \mathrm { OH } ) _ { 2 }(OH)2​ ,from Fe2+\mathrm { Fe } ^ { 2 + }Fe2+ and O H−\mathrm { H } ^ { - }H− not considered an oxidation-reduction 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

For the following acid-base reaction,identify what is formed in the space marked. H₂SO₄ + KOH ⇌ KHSO₄ + ???

How many electrons are transferred from iron atoms to oxygen atoms in the formation of two molecules of iron hydroxide,Fe $( \mathrm { OH } ) _ { 2 }$ ?

In the oxidation-reduction reaction Mg(s)+ $\mathrm { Cu } ^ { 2 + }$ (aq)? 3 $\mathrm { Mg } ^ { 2 + }$ (aq)+ Cu(s),which atom or ion is reduced? Which atom or ion is oxidized?

Upon combustion,about how many grams of water vapor are produced from every 16 grams of methane, $\mathrm { CH } _ { 4 }$ ? $\mathrm { CH } _ { 4 }$ + 2 $\mathrm { O } _ { 2 }$ ? $\mathrm { CO } _ { 2 }$ + 2 $\mathrm { H } _ { 2 }$ O

In a battery,the following oxidation-reduction reactions are taking place: Mn₂O₃ + ZnO → 2 MnO₂ + Zn What is being formed at the cathode?

In one type of fuel cell,the following oxidation-reduction reactions are taking place: 2 H₂+ O₂ → 2 H₂O What is the oxidant?

Which of the following species is undergoing oxidation? 2 CuBr → 2Cu + Br₂

In a battery,the following oxidation-reduction reactions are taking place: Mn₂O₃ + ZnO → 2 MnO₂ + Zn What is undergoing an oxidation as written?

In a battery,the following two oxidation-reduction reactions are taking place: rxn A: Zn + 2 OH^- → ZnO + H₂O + 2e^- Rxn B: 2 MnO₂ + H₂O + 2e^- → Mn₂O₃ + 2 OH^- What is undergoing oxidation?

According to the following reaction,which molecule is acting as an acid? OH^- + NH₄⁺ → H₂O + NH₃

Why is the formation of iron hydroxide,Fe $( \mathrm { OH } ) _ { 2 }$ ,from $\mathrm { Fe } ^ { 2 + }$ and O $\mathrm { H } ^ { - }$ not considered an oxidation-reduction reaction?