Question 1

Jewelry is often manufactured by electroplating an expensive metal such as gold over a cheaper metal.A setup for this process can be sketched as follows:  What would happen if the battery connections were suddenly reversed?

Accepted Answer

A) The ring would continue to electroplate with gold. 
B) Gold ions in solution would get reduced and settle to the bottom of the container. 
C) Gold ions in solution would begin to electroplate onto the gold electrode. 
D) All electrolysis would stop.

Question 2

If you had a 1 M solution of a weak acid what would be its pH?

Accepted Answer

A) 0 
B) 6 
C) 7 
D) 8 
E) 13

Question 3

-In the above diagram,which atom behaves as the oxidizing agent,the lighter colored atom or the darker colored atom?

Accepted Answer

A) Both atoms behave as the oxidizing agent. 
B) Neither of the atoms behave as the oxidizing agent. 
C) The darker colored atom behaves as the oxidizing agent. 
D) The lighter colored atom behaves as the oxidizing agent.

Question 4

Which of the following statements about electrochemistry is not true?

Accepted Answer

A) It is the study of how electrical energy and chemical reactions are related. 
B) It involves the use of a set of oxidation-reduction reactions to produce electrical current. 
C) It involves the use of electrical current to produce an oxidation-reduction reaction. 
D) It is the study of how electrons are transferred from one chemical compound to another. 
E) All of the above are true.

Question 5

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

Accepted Answer

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

Question 6

The main component of bleach is sodium hypochlorite,NaOCl,which consists of sodium ions,Na?,and hypochlorite ions, $\mathrm { OCl } ^ { 2 }$ What products are formed when this compound is reacted with the hydrochloric acid,HCl,of toilet bowl cleaner?

Accepted Answer

A) The products are NaCl, $\mathrm { O } _ { 2 }$ ,and $\mathrm { HClO } _ { 2 }$ . 
B) The products are NaOH, $\mathrm { H } _ { 2 }$ O,and $\mathrm { Cl } _ { 2 }$ . 
C) The products are NaCl and HOCl. 
D) The products are NaOH, $\mathrm { O } _ { 2 }$ ,and $\mathrm { Cl } _ { 2 }$

Question 7

Why is recycling of aluminum better for the environment than electrolysis of bauxite (an aluminum ore)?

Accepted Answer

A) It takes less energy to recycle aluminum. 
B) Electrolysis releases harmful gases into the atmosphere. 
C) The bauxite is extremely rare and there is very little aluminum in the world. 
D) Electricity is extremely cheap and it is better to use cheap electricity. 
E) none of the above

Question 8

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

Accepted Answer

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

Question 9

Sodium metal is

Accepted Answer

A) oxidized in the production of aluminum. 
B) reduced in the production of aluminum. 
C) both oxidized and reduced in the production of aluminum. 
D) neither oxidized nor reduced in the production of aluminum.

Question 10

Clorox is a laundry bleaching agent used to remove stains from white clothes.Suggest why the name begins with Clor- and ends with -ox.

Accepted Answer

A) Clor~ because it has chlorine,~ox because it is as strong as an ox. 
B) The active ingredient contains chlorine atoms,which behave as strong oxidizing agents. 
C) Chlor~ because it has chlorine ions,~ox because it is reduced. 
D) Chlor~ because it has chlorine ions,~ox because it uses oxygen.

Question 11

In a battery,the following two oxidation-reduction reactions are taking place: rxn A: Zn → Zn+2 + 2e-
Rxn B: 2 NH4+ + 2e- → 2 NH3 + H2
Which reaction is taking place at the anode?

Accepted Answer

A) rxn A 
B) rxn B 
C) Both reactions are happening at both the anode and cathode. 
D) Both reactions are happening at the electrode. 
E) The reaction takes place at the electrode,not the anode.

Question 12

For the following reaction,identify whether the compound in bold is behaving as an acid or a base. H3PO4 + H2O ⇌ H2PO4- + H3O+

Accepted Answer

A) acid 
B) base 
C) neither 
D) both 
E) none of the above

Question 13

Rust has a tendency to form when iron in contact with water reacts according to the following reaction: 4 Fe + 3 O2 → 2 Fe2O3
What is happening at the anodic region?

Accepted Answer

A) Iron is being oxidized. 
B) Oxygen is being oxidized. 
C) Oxygen is being reduced. 
D) Iron is being reduced. 
E) none of the above

Question 14

Which of the following statements about strong or weak acids is true?

Accepted Answer

A) A weak acid and a strong acid at the same concentration are equally corrosive. 
B) A weak acid readily forms ions when dissolved in water. 
C) A strong acid will never react with a strong base. 
D) A weak acid will react with a strong base.

Question 15

Why don't the electrodes of a fuel cell deteriorate the way the electrodes of a battery do?

Accepted Answer

A) As long as fuel is supplied,fuel cells don't run down,but car batteries die when the electron-producing chemicals are consumed. 
B) Fuel cell electrodes are made of graphite,which does not deteriorate. 
C) Fuel cell electrodes are self-replenishing thanks to the KOH-containing paste. 
D) Fuel cell do not use electrodes,so there are none to deteriorate.

Question 16

For the following acid-base reaction,identify what compound is formed in the space marked. HNO3 + KOH ⇌ ???? + H2O

Accepted Answer

A) KNO3 
B) H3ONO3 
C) KOH2 
D) KOH2NO3 
E) none of the above

Question 17

A weak acid is added to a concentrated solution of hydrochloric acid.Does the solution become more or less acidic?

Accepted Answer

A) More acidic,since there are more hydronium ions being added to the solution. 
B) Less acidic,since the solution becomes more dilute with a less concentrated solution of hydronium ions being added to the solution. 
C) No change in acidity,since the concentration of the hydrochloric acid is too high to be changed by the weak solution. 
D) Less acidic since the concentration of hydroxide ions will increase.

Question 18

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

Accepted Answer

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

Question 19

Why do we use the pH scale to indicate the acidity of a solution rather than simply stating the concentration of hydronium ions?

Accepted Answer

A) It includes the concentration of hydronium and hydroxide ions. 
B) It is used because the general public understands it. 
C) It is more accurate to use the pH scale. 
D) It is more convenient,since the concentration of hydronium ions is so small.

Question 20

For the following acid-base reaction,identify what compound is formed in the space marked. HCl + KOH ⇌ ???? + H2O

Accepted Answer

A) KCl 
B) H3OCl 
C) KOH2 
D) KOH2Cl 
E) none of the above

Exam 18: Two Classes of Chemical Reactions

Jewelry is often manufactured by electroplating an expensive metal such as gold over a cheaper metal.A setup for this process can be sketched as follows: What would happen if the battery connections were suddenly reversed?

If you had a 1 M solution of a weak acid what would be its pH?

-In the above diagram,which atom behaves as the oxidizing agent,the lighter colored atom or the darker colored atom?

Which of the following statements about electrochemistry is not true?

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

The main component of bleach is sodium hypochlorite,NaOCl,which consists of sodium ions,Na?,and hypochlorite ions, $\mathrm { OCl } ^ { 2 }$ What products are formed when this compound is reacted with the hydrochloric acid,HCl,of toilet bowl cleaner?

Why is recycling of aluminum better for the environment than electrolysis of bauxite (an aluminum ore) ?

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

Sodium metal is

Clorox is a laundry bleaching agent used to remove stains from white clothes.Suggest why the name begins with Clor- and ends with -ox.

In a battery,the following two oxidation-reduction reactions are taking place: rxn A: Zn → Zn⁺² + 2e^- Rxn B: 2 NH₄⁺ + 2e^- → 2 NH₃ + H₂ Which reaction is taking place at the anode?

For the following reaction,identify whether the compound in bold is behaving as an acid or a base. H₃PO₄ + H₂O ⇌ H₂PO₄^- + H₃O⁺

Rust has a tendency to form when iron in contact with water reacts according to the following reaction: 4 Fe + 3 O₂ → 2 Fe₂O₃ _{What is happening at the anodic region}_?

Which of the following statements about strong or weak acids is true?

Why don't the electrodes of a fuel cell deteriorate the way the electrodes of a battery do?

For the following acid-base reaction,identify what compound is formed in the space marked. HNO₃ + KOH ⇌ ???? + H₂O

A weak acid is added to a concentrated solution of hydrochloric acid.Does the solution become more or less acidic?

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

Why do we use the pH scale to indicate the acidity of a solution rather than simply stating the concentration of hydronium ions?

For the following acid-base reaction,identify what compound is formed in the space marked. HCl + KOH ⇌ ???? + H₂O

Exam 18: Two Classes of Chemical Reactions

Jewelry is often manufactured by electroplating an expensive metal such as gold over a cheaper metal.A setup for this process can be sketched as follows: What would happen if the battery connections were suddenly reversed?

If you had a 1 M solution of a weak acid what would be its pH?

-In the above diagram,which atom behaves as the oxidizing agent,the lighter colored atom or the darker colored atom?

Which of the following statements about electrochemistry is not true?

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

The main component of bleach is sodium hypochlorite,NaOCl,which consists of sodium ions,Na?,and hypochlorite ions, OCl2\mathrm { OCl } ^ { 2 }OCl2 What products are formed when this compound is reacted with the hydrochloric acid,HCl,of toilet bowl cleaner?

Why is recycling of aluminum better for the environment than electrolysis of bauxite (an aluminum ore) ?

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

Sodium metal is

Clorox is a laundry bleaching agent used to remove stains from white clothes.Suggest why the name begins with Clor- and ends with -ox.

In a battery,the following two oxidation-reduction reactions are taking place: rxn A: Zn → Zn+2 + 2e- Rxn B: 2 NH4+ + 2e- → 2 NH3 + H2 Which reaction is taking place at the anode?

For the following reaction,identify whether the compound in bold is behaving as an acid or a base. H3PO4 + H2O ⇌ H2PO4- + H3O+

Rust has a tendency to form when iron in contact with water reacts according to the following reaction: 4 Fe + 3 O2 → 2 Fe2O3 What is happening at the anodic region?

Which of the following statements about strong or weak acids is true?

Why don't the electrodes of a fuel cell deteriorate the way the electrodes of a battery do?

For the following acid-base reaction,identify what compound is formed in the space marked. HNO3 + KOH ⇌ ???? + H2O

A weak acid is added to a concentrated solution of hydrochloric acid.Does the solution become more or less acidic?

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

Why do we use the pH scale to indicate the acidity of a solution rather than simply stating the concentration of hydronium ions?

For the following acid-base reaction,identify what compound is formed in the space marked. HCl + KOH ⇌ ???? + H2O

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

The main component of bleach is sodium hypochlorite,NaOCl,which consists of sodium ions,Na?,and hypochlorite ions, $\mathrm { OCl } ^ { 2 }$ What products are formed when this compound is reacted with the hydrochloric acid,HCl,of toilet bowl cleaner?

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

In a battery,the following two oxidation-reduction reactions are taking place: rxn A: Zn → Zn⁺² + 2e^- Rxn B: 2 NH₄⁺ + 2e^- → 2 NH₃ + H₂ Which reaction is taking place at the anode?

For the following reaction,identify whether the compound in bold is behaving as an acid or a base. H₃PO₄ + H₂O ⇌ H₂PO₄^- + H₃O⁺

Rust has a tendency to form when iron in contact with water reacts according to the following reaction: 4 Fe + 3 O₂ → 2 Fe₂O₃ _{What is happening at the anodic region}_?

For the following acid-base reaction,identify what compound is formed in the space marked. HNO₃ + KOH ⇌ ???? + H₂O

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

For the following acid-base reaction,identify what compound is formed in the space marked. HCl + KOH ⇌ ???? + H₂O