Question 1

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 2

In behaving as both an acid and a base, water reacts with itself to form ________.

Accepted Answer

A)  hydronium ions, H3O+. 
B)  hydroxide ions, OH-. 
C)  more water molecules. 
D)  two of the above. 
E)  all of the above.

Question 3

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

Accepted Answer

A)  The concentration of hydroxide decreases to neutralize the excess hydronium. 
B)  The concentration of H3O+ stays the same but the ratio changes. 
C)  The concentration of H3O+ increases but the ratio stays the same. 
D)  The concentration of H3O+ increases to neutralize the excess hydroxide. 
E)  none of the above

Question 4

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 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

In the reaction below, what does the symbol ⇌ mean? OH- + NH4+ ⇌ H2O + NH3

Accepted Answer

A)  It means that the forward and backward reactions are happening at the same time. 
B)  It means that the reaction cannot decide which way to go. 
C)  It means that the forward reaction does not progress. 
D)  It means that the backward reaction happens as fast as the forward reaction and so the proton is not transferred at all. 
E)  none of the above

Question 7

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

Accepted Answer

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

Question 8

Which of the following items would you use to make a basic buffer solution?

Accepted Answer

A)  acetic acid (a weak acid) and hydrochloric acid (a strong acid) 
B)  sodium hydroxide (a strong base) and sodium chloride 
C)  acetic acid (a weak acid) and sodium acetate 
D)  hydrochloric acid (a strong acid) and sodium hydroxide (a strong base) 
E)  ammonium hydroxide (a weak base) and ammonium chloride

Question 9

What is the hydroxide ion concentration in an aqueous solution when the hydronium ion concentration equals 1 ×  moles per liter?

Accepted Answer

A)  The concentration of hydroxide ions is 1 ×  moles per liter. 
B)  The concentration of hydroxide ions is 1 ×  moles per liter. 
C)  The concentration of hydroxide ions is 1 ×  moles per liter. 
D)  The concentration of hydroxide ions is 1 ×  moles per liter.

Question 10

Does a water molecule become more or less polar when bound to a metal ion, such as  ? Why? (Hint: How might the electrons of the O-H covalent bonds in water "feel" about the highly charged aluminum ion?)

Accepted Answer

A)  Less polar. Aluminum ion is so highly polar that it attracts the electrons in a water molecule to itself and away from the oxygen atom in water, causing water to lose polar character. 
B)  More polar. The electrons in the O-H bond are drawn even closer to the oxygen (and away from the hydrogen) as they are drawn towards the positive charge of the aluminum ion. 
C)  Neither. Although polarity may increase as a water molecule approaches an aluminum ion, once the water molecule becomes bound to the metal ion its polarity reverts to its original status. 
D)  Both. As a first water molecule approaches  , there is an increase in water's polarity. However, the "bond" becomes less polar when the aluminum ion has captured all six water molecules to form  O  3+.

Question 11

Why is the H-F bond so much stronger than the H-I bond?

Accepted Answer

A)  H-F is a stronger bond because hydrogen and fluorine are more similar in nature than hydrogen and iodine. Both hydrogen and fluorine are diatomic and gases at room temperature. 
B)  H-F is stronger bond because iodine forms a solid at room temperature and fluorine forms a gas. Also, iodine tends to sublime at room temperature. 
C)  H-F is stronger because the fluorine atom is smaller and closer to the hydrogen atom causing greater attraction. 
D)  Actually, H-I is stronger because the electronegativity of the iodine atom is smaller that that of the fluorine atom.

Question 12

How might you tell whether or not your toothpaste contained either calcium carbonate, CaC  , or baking soda, NaHC  , without looking at the ingredients label?

Accepted Answer

A)  if the toothpaste bubbles when heated 
B)  if the toothpaste bubbles when added to ammonia, such as window cleaner 
C)  if the toothpaste produces a salt (NaCl) when added to HCl 
D)  if the toothpaste bubbles when added to vinegar

Question 13

What is an acid?

Accepted Answer

A)  anything that donates hydrogen ions 
B)  anything that accepts hydrogen atoms 
C)  anything that donates hydrogen atoms 
D)  anything that dissolves metal 
E)  anything that donates hydronium ions

Question 14

What would the concentration of OH- be if the concentration of H3O+ was 1 × 10-8M? [H3O+] × [OH-] = Kw = 1 × 10-14

Accepted Answer

A)  1 × 10-14 
B)  1 × 10-6 
C)  1 × 108 
D)  1 × 106 
E)  1 × 10-8

Question 15

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

Accepted Answer

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

Question 16

What best describes what happens when an acid such as HCl is mixed with water?

Accepted Answer

A)  The proton chemically bonded to the chlorine is transferred to a water molecule and forms a chloride ion and a hydronium ion. 
B)  A proton from the chlorine nucleus is ejected and captured by a water molecule to form a negatively charged HCl and a new hydronium ion. 
C)  A hydroxide ion from the water is transferred to the HCl molecule to form a proton and hydronium ion. 
D)  HCl is not an acid. 
E)  none of the above

Question 17

What atom in the ammonium ion,  ⁺ bears the positive charge?

Accepted Answer

A)  the nitrogen atom 
B)  the hydrogen atom 
C)  Neither atom bears a positive charge. 
D)  Nitrogen and hydrogen equally share the positive charge.

Question 18

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 19

What would the concentration of H3O+ be if the concentration of OH- was 1 × 10-1M? [H3O+] × [OH-] = Kw = 1 × 10-14

Accepted Answer

A)  1 × 10-3 
B)  1 × 10-2 
C)  1 × 10-4 
D)  1 × 1013 
E)  none of the above

Question 20

Which of the above illustrations shows a neutral aqueous solution?

Accepted Answer

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

Exam 10: Acids and Bases in Our Environment

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

In behaving as both an acid and a base, water reacts with itself to form ________.

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

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

In the reaction below, what does the symbol ⇌ mean? OH^- + NH₄⁺ ⇌ H₂O + NH₃

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

Which of the following items would you use to make a basic buffer solution?

What is the hydroxide ion concentration in an aqueous solution when the hydronium ion concentration equals 1 × moles per liter?

Does a water molecule become more or less polar when bound to a metal ion, such as ? Why? (Hint: How might the electrons of the O-H covalent bonds in water "feel" about the highly charged aluminum ion?)

Why is the H-F bond so much stronger than the H-I bond?

How might you tell whether or not your toothpaste contained either calcium carbonate, CaC , or baking soda, NaHC , without looking at the ingredients label?

What is an acid?

What would the concentration of OH^- be if the concentration of H₃O⁺ was 1 × 10^-8M? [H₃O⁺] × [OH^-] = K_w= 1 × 10^-14

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

What best describes what happens when an acid such as HCl is mixed with water?

What atom in the ammonium ion, _⁺ bears the positive charge?

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

What would the concentration of H₃O⁺ be if the concentration of OH^- was 1 × 10^-1M? [H₃O⁺] × [OH^-] = K_w= 1 × 10^-14

Which of the above illustrations shows a neutral aqueous solution?

Exam 10: Acids and Bases in Our Environment

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

In behaving as both an acid and a base, water reacts with itself to form ________.

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

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

In the reaction below, what does the symbol ⇌ mean? OH- + NH4+ ⇌ H2O + NH3

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

Which of the following items would you use to make a basic buffer solution?

What is the hydroxide ion concentration in an aqueous solution when the hydronium ion concentration equals 1 × moles per liter?

Does a water molecule become more or less polar when bound to a metal ion, such as ? Why? (Hint: How might the electrons of the O-H covalent bonds in water "feel" about the highly charged aluminum ion?)

Why is the H-F bond so much stronger than the H-I bond?

How might you tell whether or not your toothpaste contained either calcium carbonate, CaC , or baking soda, NaHC , without looking at the ingredients label?

What is an acid?

What would the concentration of OH- be if the concentration of H3O+ was 1 × 10-8M? [H3O+] × [OH-] = Kw = 1 × 10-14

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

What best describes what happens when an acid such as HCl is mixed with water?

What atom in the ammonium ion, ⁺ bears the positive charge?

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

What would the concentration of H3O+ be if the concentration of OH- was 1 × 10-1M? [H3O+] × [OH-] = Kw = 1 × 10-14

Which of the above illustrations shows a neutral aqueous solution?

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

In the reaction below, what does the symbol ⇌ mean? OH^- + NH₄⁺ ⇌ H₂O + NH₃

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

What would the concentration of OH^- be if the concentration of H₃O⁺ was 1 × 10^-8M? [H₃O⁺] × [OH^-] = K_w= 1 × 10^-14

What atom in the ammonium ion, _⁺ bears the positive charge?

What would the concentration of H₃O⁺ be if the concentration of OH^- was 1 × 10^-1M? [H₃O⁺] × [OH^-] = K_w= 1 × 10^-14