Question 1

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) 7,000 M 
E) 10

Question 2

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.

Question 3

The following set of redox reactions takes place as shown. Container A Container B
Fe → Fe+2 + 2e- Cu+2 + 2e- → Cu
If you had two containers filled with the ion solution described above with a wire connecting a piece of iron (in container A) and a piece of copper (in container B) and a salt-bridge connecting the two containers, describe what happens.

Accepted Answer

A)  A little bit of iron is converted into iron ions and a little bit of copper ion is converted into copper metal. 
B)  All of the iron is transformed into iron ions and all of the copper is transformed into copper ions. 
C)  All of the iron is transformed into iron ions and all of the copper ions are transformed into copper metal. 
D)  All of the iron ions are transformed into iron metal and all of the copper is transformed into copper ions. 
E)  All of the iron ions are transformed into iron metal and all of the copper is transformed into copper metal.

Question 4

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 cathodic 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 5

The following set of redox reactions takes place as shown. Container A Container B
Fe → Fe+2 + 2e- Cu+2 + 2e- → Cu
If you had two containers filled with the ion solution described above with only a wire connecting a piece of iron (in container A) and a piece of copper (in container B), which way do the electrons flow?

Accepted Answer

A)  There is no continuous flow of electrons. 
B)  The electrons from from container A to container B. 
C)  The electrons flow from container B to container A. 
D)  The electrons flow back and forth between the two containers. 
E)  The electrons only move in the containers they originate in.

Question 6

The following set of redox reactions takes place when iron is dipped in a solution of copper ions. Fe → Fe+2 + 2e-
Cu+2 + 2e- → Cu
Which of the following describes what is happening on the surface of the iron?

Accepted Answer

A) The copper starts to plate out on iron. 
B) The iron rusts in the water. 
C) The iron starts to plate out on the copper. 
D) The iron corrodes the copper. 
E) none of the above

Question 7

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.

Question 8

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.

Question 9

Which element is closer to the upper right corner of the periodic table, the one indicated by the lighter colored atoms or the darker colored atoms?

Accepted Answer

A) the element indicated by the darker color 
B) the element indicated by the lighter color 
C) More information is needed in order to determine which element is closer to the upper right of the periodic table. 
D) Both the lighter and darker colored elements are likely found at the upper right corner of the periodic table.

Question 10

Copper atoms have a greater tendency to be reduced than iron atoms do. Was this good news or bad news for the Statue of Liberty, whose copper exterior was originally held together by steel rivets?

Accepted Answer

A) This was good news since the steel rivets prevented the copper from eroding. 
B) Electrons will preferentially flow from the iron to the copper and then onto oxygen. Corrosion is thus accelerated around the interface of these two metals. 
C) This combination of metals have no effect on each other and that is why engineers chose to use them together. 
D) This combination of metals caused the copper to oxidize and turn green.

Question 11

Which of the above illustrations shows an acidic aqueous solution?

Accepted Answer

A) A 
B) B 
C) C 
D) All of the above are neutral solutions. 
E) none of the above

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

Which of the following compounds would least likely act as an acid?

Accepted Answer

A) SO4-2 
B) HSO4-1 
C) H2SO4 
D) NH3 
E) CH3CO2H

Question 14

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 15

Which of the following statements about strong and weak bases is not true?

Accepted Answer

A) A weak base does not completely dissociate in water. 
B) A weak base will not react with a strong acid. 
C) A strong base can be extremely corrosive. 
D) A strong base will readily accept protons from even weak acids. 
E) All of the above are untrue.

Question 16

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

Accepted Answer

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

Question 17

Cutting back on the pollutants that cause acid rain is one solution to the problem of acidified lakes. Suggest another.

Accepted Answer

A) stop using NaCl to salt the roads in the winter 
B) add a neutralizing substance such as limestone 
C) add ammonium ions to the lakes 
D) add chlorine and filter the water to remove any acidity in the lake

Question 18

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

Question 19

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

Question 20

What is the hydroxide ion concentration in an aqueous solution where the pH = 5?

Accepted Answer

A) The hydronium ion concentration equals 1 × 10-9. 
B) The hydronium ion concentration equals 1 × 10-7. 
C) The hydronium ion concentration equals 1 × 10-5. 
D) The hydronium ion concentration equals 1 ×10-3.

Exam 18: Two Classes of Chemical Reactions

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

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

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 cathodic region?}

The following set of redox reactions takes place when iron is dipped in a solution of copper ions. Fe → Fe⁺² + 2e- Cu⁺² + 2e- → Cu Which of the following describes what is happening on the surface of the iron?

What is a base?

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

Which element is closer to the upper right corner of the periodic table, the one indicated by the lighter colored atoms or the darker colored atoms?

Copper atoms have a greater tendency to be reduced than iron atoms do. Was this good news or bad news for the Statue of Liberty, whose copper exterior was originally held together by steel rivets?

Which of the above illustrations shows an acidic aqueous solution?

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

Which of the following compounds would least likely act as an acid?

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

Which of the following statements about strong and weak bases is not true?

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

Cutting back on the pollutants that cause acid rain is one solution to the problem of acidified lakes. Suggest another.

What is the purpose of a salt-bridge?

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

What is the hydroxide ion concentration in an aqueous solution where the pH = 5?

Exam 18: Two Classes of Chemical Reactions

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

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

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 cathodic region?

The following set of redox reactions takes place when iron is dipped in a solution of copper ions. Fe → Fe+2 + 2e- Cu+2 + 2e- → Cu Which of the following describes what is happening on the surface of the iron?

What is a base?

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

Which element is closer to the upper right corner of the periodic table, the one indicated by the lighter colored atoms or the darker colored atoms?

Copper atoms have a greater tendency to be reduced than iron atoms do. Was this good news or bad news for the Statue of Liberty, whose copper exterior was originally held together by steel rivets?

Which of the above illustrations shows an acidic aqueous solution?

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

Which of the following compounds would least likely act as an acid?

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

Which of the following statements about strong and weak bases is not true?

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

Cutting back on the pollutants that cause acid rain is one solution to the problem of acidified lakes. Suggest another.

What is the purpose of a salt-bridge?

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

What is the hydroxide ion concentration in an aqueous solution where the pH = 5?

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 cathodic region?}

The following set of redox reactions takes place when iron is dipped in a solution of copper ions. Fe → Fe⁺² + 2e- Cu⁺² + 2e- → Cu Which of the following describes what is happening on the surface of the iron?

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

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

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