Question 1

Pour vinegar onto beach sand from the Caribbean and the result is a lot of froth and bubbles. Pour vinegar onto beach sand from California, however, and nothing happens. Why?

Accepted Answer

A)  Beaches in tropical climates generally have remnants of volcanic deposit not present in California sand. These deposits contain soil with organic residue. Vinegar's acetic acid reacts with organic matter. 
B)  The pH of the warm sands of tropical waters is well into the basic range, unlike the beach sand in California. Therefore, the acidic vinegar reacts with Caribbean beach sand but not with sand from California. 
C)  Beach sand from the Caribbean and many other tropical climates is made primarily of the calcium carbonate remains of coral and shelled creatures. Vinegar is an acid and the calcium carbonate is a base. 
D)  Caribbean beach sand contains deposits from the mouth of the Mississippi river which carries with it a great deal of contamination from urban waste. These warm water contaminates react with the acid in vinegar.

Question 2

Adding more carbon dioxide to the atmosphere causes the concentration of carbonates in the ocean to ________.

Accepted Answer

A)  increase 
B)  decrease 
C)  stay the same because of a negative feedback mechanism 
D)  stay the same because of a positive feedback mechanism

Question 3

The hydroxide ion, HO-, is a ________.

Accepted Answer

A)  unique form of water 
B)  very strong acid 
C)  polyatomic ion 
D)  proton donator

Question 4

What is the relationship between the hydroxide ion and a water molecule?

Accepted Answer

A)  A hydroxide ion is a water molecule plus a proton. 
B)  A hydroxide ion and a water molecule are the same things. 
C)  A hydroxide ion is a water molecule minus a hydrogen nucleus. 
D)  A hydroxide ion is a water molecule plus two extra electrons.

Question 5

Which of the following compounds could never act as an acid?

Accepted Answer

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

Question 6

Identify the acid or base behavior of each substance in these reactions: HS   +  O ⇌ O  +  S

Accepted Answer

A)  HS   acts as an acid,  O acts as a base, O  acts as an acid,  S  acts as a base. 
B)  HS   acts as an base,  O acts as a acid, O  acts as an acid,  S  acts as a base. 
C)  HS   acts as an acid,  O acts as a base, O  acts as an base,  S  acts as a acid. 
D)  HS   acts as an base,  O acts as a acid, O  acts as an base,  S  acts as a acid.

Question 7

What is pH?

Accepted Answer

A)  It is a numerical scale used to represent acidity or basicity. 
B)  It is the negative of the log of the hydronium ion concentration. 
C)  It is the negative of the log of the acidity of a solution. 
D)  It is the F sound. 
E)  both A and B

Question 8

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

Accepted Answer

A)  1 
B)  6 
C)  7 
D)  8 
E)  13

Question 9

Acetic acid, shown below, has 4 hydrogen atoms-one bonded to an oxygen and three bonded to a carbon. When this molecule behaves as an acid, it donates only the hydrogen bonded to the oxygen. The hydrogens bonded to the carbon remain intact. Why?

Accepted Answer

A)  The oxygen is much better at accommodating a negative charge than is carbon. 
B)  The hydrogen attached to the oxygen extends farther away from the center of the molecule. 
C)  The carbon is bonded to three hydrogens while the oxygen is bonded to only one hydrogen. 
D)  The oxygen within acetic acid has two lone pairs of electrons that help to destabilize the oxygen-hydrogen bond.

Question 10

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

Question 11

If you were to increase the pH of rain water the concentration of dissolved CO2 would ________.

Accepted Answer

A)  increase because the acid form is neutralized 
B)  decrease because you are adding acid 
C)  decrease because the acid form is neutralized 
D)  increase because you are adding acid

Question 12

If you had a 1 M solution of a strong base what would be its pH?

Accepted Answer

A)  1 
B)  6 
C)  7 
D)  8 
E)  13

Question 13

Which of the following statements describes a basic solution?

Accepted Answer

A)  [H3O+] > [OH-] 
B)  [H3O+] -] 
C)  [H3O+] × [OH-] ≠ 1 × 10-14 
D)  [H3O+]/[OH-] = 1 × 10-14 
E)  [H3O+]/[OH-] = 1

Question 14

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 15

Sodium bicarbonate, NaHC  , is the active ingredient of baking soda. Compare its structure carefully with the weak acids and bases presented in this chapter and explain how this compound by itself in solution (with no other components) moderates changes in pH.

Accepted Answer

A)  Sodium bicarbonate is like two buffer components combined into one molecule, the hydrogen end of the molecule is similar to a weak base, and the sodium end is like a weak acid. 
B)  Sodium bicarbonate is like two buffer components combined into one molecule, the hydrogen end of the molecule is similar to a weak acid, and the sodium end is like a weak base. 
C)  Sodium bicarbonate is like a buffer, the hydrogen end of the molecule is similar to a weak base. 
D)  Sodium bicarbonate is like a buffer, the sodium end of the molecule is like a weak acid.

Question 16

Sodium hydroxide, NaOH, is a very strong base. If a concentrated solution of this base were to spill on a latex glove you were wearing, it would feel like regular water. If the solution were to land directly on your skin, however, it would feel very slippery. Why?

Accepted Answer

A)  The sodium hydroxide solution is reacting with your skin oils and transforming them into soap, which feels slippery. 
B)  The strong NaOH solution lifts the oil directly out of the skin cells and you feel the oil as a slippery sensation as it floats on the skin surface. 
C)  NaOH kills skin cells on contact. The dissolved skin cells feel slippery because the cells still contain the natural oils of the skin. 
D)  One of the properties of sodium hydroxide is that it is slippery. You are simply not able to sense the the slippery feel through a latex glove.

Question 17

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

Accepted Answer

A)  A weak base completely separates into ions in water. 
B)  A weak base will not react with a strong acid. 
C)  A strong base is always corrosive. 
D)  A strong base will readily accept protons from even weak acids.

Question 18

In the following buffer system, what happens to the concentration of the highlighted molecule if you add base in the form of OH-? HF + NaF + H2O ⇌ F- + H3O+ + Na+

Accepted Answer

A)  increases 
B)  decreases 
C)  stays about the same 
D)  Buffers do not change. 
E)  none of the above

Question 19

Which is the stronger acid: H-F or H-I?

Accepted Answer

A)  H-F, because the electronegativity of fluorine is higher than that of iodine making the H-F bond more polar and more likely to release the hydrogen ion to solution. 
B)  H-F, because acid strength for binary acids decreases "down the group" of the periodic table. 
C)  H-I, because iodine releases the hydrogen in order to form  (s) at room temperature. 
D)  H-I, because the H-I bond is weaker and so it is easier to break to form hydrogen ions.

Question 20

According to the following reaction, which molecule is acting as an acid? H2O + H2SO4 → H3O+ + HSO4-

Accepted Answer

A)  H2SO4 
B)  H2O 
C)  H3O+ 
D)  HSO4- 
E)  none of the above

Exam 10: Acids and Bases in Our Environment

Pour vinegar onto beach sand from the Caribbean and the result is a lot of froth and bubbles. Pour vinegar onto beach sand from California, however, and nothing happens. Why?

Adding more carbon dioxide to the atmosphere causes the concentration of carbonates in the ocean to ________.

The hydroxide ion, HO^-, is a ________.

What is the relationship between the hydroxide ion and a water molecule?

Which of the following compounds could never act as an acid?

Identify the acid or base behavior of each substance in these reactions: HS + O ⇌ O + S

What is pH?

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

Acetic acid, shown below, has 4 hydrogen atoms-one bonded to an oxygen and three bonded to a carbon. When this molecule behaves as an acid, it donates only the hydrogen bonded to the oxygen. The hydrogens bonded to the carbon remain intact. Why?

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

If you were to increase the pH of rain water the concentration of dissolved CO₂would ________.

If you had a 1 M solution of a strong base what would be its pH?

Which of the following statements describes a basic solution?

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

Sodium bicarbonate, NaHC , is the active ingredient of baking soda. Compare its structure carefully with the weak acids and bases presented in this chapter and explain how this compound by itself in solution (with no other components) moderates changes in pH.

Sodium hydroxide, NaOH, is a very strong base. If a concentrated solution of this base were to spill on a latex glove you were wearing, it would feel like regular water. If the solution were to land directly on your skin, however, it would feel very slippery. Why?

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

In the following buffer system, what happens to the concentration of the highlighted molecule if you add base in the form of OH^-? HF + NaF + H₂O ⇌ F^- + H₃O⁺_{+ Na}+

Which is the stronger acid: H-F or H-I?

According to the following reaction, which molecule is acting as an acid? H₂O + H₂SO₄ → H₃O⁺ + HSO₄^-