Chem Exam 4

Question 1

Which of the following statements is true concerning buffers?

• Buffers can contain a weak acid and its conjugate base
• Buffers resist change in pH when additional acids or bases are added
• Buffers have a limit, called buffer capacity, of how much additional acid or base can be added.
• Buffers can contain a weak base and its conjugate acid
• All of the above statements are true when concerning buffers

Answer 1

• All of the above statements are true when concerning buffers

Question 2

What is the conjugate acid of HCO3⁻?

• H3O+
• OH⁻
• H2CO3
• H2O
• CO32-

Answer 2

• H2CO3

Question 3

Which of the following is not a chemical interaction consideration for drug binding?

• Hydrophobic interactions
• Electrostatic interactions
• Agostic interactions
• Stereospecific interactions

Answer 3

• Agostic interactions

Question 3

Which of the following is a Br∅nsted-Lowry base?
* CH4
* HCN
* NH3
* Cl2

Answer 3

• NH3

Question 4

Which term is used to describe the extent to which a drug produces its desired effect?

• Affinity
• Efficacy
• Toxicity
• Potency

Answer 4

• Efficacy

Question 4

Which drug category binds irreversibly to a receptor?

• Non-competetive antagonist
• Endogenous agonist
• Exogenous agonist
• Competetive antagonist

Answer 4

• Non-competetive antagonist

Question 5

Which of the following does not affect the bioavailability of a drug?

• Drug temperature
• Drug stability
• Drug metabolism
• Drug interactions
• Molecular weight of a drug

Answer 5

• Drug temperature

Question 5

How many hydrogen bond donors are in magnocurarine?
___

Answer 5

2

Question 5

Would the following compound (logP = 2.97) be considered a good drug candidate? (Select All)

• The compound has too many total hydrogen bond donors and acceptors.
• The compound would be considered a good drug candidate.
• The logP for the compound is too low.
• The molecular weight of the compound is too high.
• The compound contains multiple structural alerts (toxicophores)
• The compound contains one structural alerts (toxicophores)
• The compound contains no structural alerts (toxicophores)
• The compound would not be considered a good drug candidate.
• The logP for the compound is too high.

Answer 5

• The compound would be considered a good drug candidate.
• Would the following compound (logP = 2.97) be considered a good drug candidate? (Select All)

Question 6

Magnocurarine is a natural product isolated from a flowering herb that has been investigated for its potential as a muscle relaxant. From the structure below, which portion would contain the strongest intermolecular force?

• 3
• 4
• 1
• 2

Answer 6

• 2

Question 7

How many hydrogen bond acceptors are in magnocurarine?

Answer 7

3

Question 7

Which of the following solutions would have the most basic pH? Assume that they are all 0.10 M in acid at 25C. The acid is followed by its Ka value.

• HNO2, 4.6 × 10-4
• HF, 3.5 × 10-4
• HCHO2, 1.8 × 10-4
• HClO2, 1.1 × 10-2
• HCN, 4.9 × 10-10

Answer 7

• HCN, 4.9 × 10-10

Question 8

Which of the following statements would be true about imipenem (log P = -3.80)?

• Imipenem is fairly lipid soluble, but would still require active transport to cross membranes.
• Imipenem has high water solubility requiring active transport to cross membranes.
• Imipenem is fairly lipid soluble and would have no trouble crossing membranes.
• Imipenem has high water solubility and would be able to cross membranes via diffusion.

Answer 8

• Imipenem has high water solubility requiring active transport to cross membranes.

Question 8

Determine the pH of a 0.023 M HNO3 solution.

Answer 8

Correct answer:
1.638272164

Question 8

How many hydrogen bond acceptors are in imipenim?

Answer 8

7

Question 8

How many hydrogen bond donors are in imipenim?

Answer 8

4

Question 9

Determine the pH of a 0.265 M HClO solution. The Ka of HClO is 2.9 × 10^-8. (Report your answer to two decimal places)

Answer 9

Correct answer:
4.06

Question 9

Determine the pH of a 0.188 M NH3 solution at 25C. (Kb = 1.72 x 10^-5) (Report your answer to two decimal places).

Answer 9

Correct answer:
11.25

Question 9

What is the percent ionization for the acidic drug thiopental (pKa = 7.55) in the blood stream (pH = 7.35)? (Report your answer to the nearest percent; no decimal places).

Answer 9

Correct answer:
39

Question 10

Calculate the pH of a 7.8 × 10^-6 M LiOH solution (Report your answer to two decimal places)

Answer 10

Correct answer:
8.89

Question 10

What is the pH of a buffer solution that is 0.15 M in HNO2 and 0.40 M in NaNO2 (Ka = 4.70 x 10^-4)? (Report your answer to two decimal places).

Answer 10

Correct Answer:
3.70 to 3.80 inclusive

Question 10

Calculate the pH of a buffer that is 0.0909 M NH3 and 0.00909 M NH4Cl (Ka = 5.8 × 10^-10 ). (Report your answer to two decimal places).

Answer 10

Correct answer:
10.24

Question 11

What is the pH of a buffer that is 0.25 M in guanidine and 5.50 M in guanidine hydrochloride (Ka = 2.5 x 10^-14)? (Report your answer to two decimal places).

Answer 11

Correct answer:
12.26

Question 12

Calculate the blood pH for a patient exhibiting [bicarbonate] = 29 mM and blood CO2 levels = 47 mmHg (Report your answer to two decimal places).

Answer 12

Correct answer:
7.41

Question 12

What is the pH of a 1.25 x 10^-3 solution of Ca(OH)2? Report your answer to two decimal places (i.e. 3.25).

Answer 12

Correct Answer: 11.35 to 11.45 inclusive

Question 12

What is the percent ionization of the basic drug codeine (pKa = 8.2) in the intesitines (pH = 7.8)? (Report your answer to the nearest percent; no decimal places).

Answer 12

Correct answer: 71

Question 12

A patient has plasma [bicarbonate] = 47 mM and blood CO2 pressure = 43 mmHg; what would the effect be on their blood pH if the blood CO2 levels were increased? * The blood pH would remain the same. * The blood pH would decrease. * The blood pH would increase. * The blood pH would decrease.

Answer 12

* The blood pH would decrease.

Question 13

What is the pH of 0.0630 solution of formic acid (KA = 1.77 x 10^-4)? Report your answer to two decimal places (i.e. 3.25).

Answer 13

Correct answer: 2.48

Question 14

What is the pH of a 0.612 M solution of pyridine (Kb = 1.78 x 10^-9)? (Report your answer to two decimal places).

Answer 14

Correct answer: 9.52

Question 15

Calculate the percent ionization for the acidic drug phenobarbital (pKA = 7.30) in the blood stream (pH = 7.4). Report your answer to two decimal places (i.e. 3.25)

Answer 15

Correct answer: 55.73

Question 15

How many hydrogen bond acceptors are found in the following compound?

Answer 15

7

Question 15

For the following compound, what would the strongest intermolecular force it would exhibit? * Hydrogen Bonding * van der Waals * Ion-Dipole * Ion-Ion * Dipole-Dipole

Answer 15

* Hydrogen Bonding

Question 15

Calculate the pH of a buffer that is 1.25 M imidazole and 0.500 M imidazole hydrochloride (KA = 1.02 x 10^-7). Report you answer to two decimal places (i.e. 3.25).

Answer 15

Correct answer: 7.39

Question 15

Would the following compound (logP = 6.29) be considered a good drug candidate? (Select All) * The compound has too many total hydrogen bond donors and acceptors. * The compound has high water solubility and would use diffusion to cross membranes. * The compound has high lipid solubility and would use diffusion to cross membranes. * The compound contains multiple structural alerts (toxicophores) * The compound contains one structural alerts (toxicophores) * The compound would have high lipid solubility requiring active transport. * The compound would not be considered a good drug candidate. * The compound contains no structural alerts (toxicophores) * The logP for the compound is too high. * The compound would be considered a good drug candidate. * The compound would have high water solubility requiring active transport. * The molecular weight of the compound is too high. * The logP for the compound is too low.

Answer 15

* The compound would have high lipid solubility requiring active transport. * The compound would not be considered a good drug candidate. * The compound contains no structural alerts (toxicophores) * The logP for the compound is too high. * The molecular weight of the compound is too high.

Question 16

How many hydrogen bond donors are found in the following compound?

Answer 16

2

Question 16

Tipranavir is an acidic drug used to treat HIV. If Tipranavir has a KA = 1.10 x 10^-6, how much of the drug would be ionized in the stomach (pH = 2)? Report your answer to two decimal places (i.e. 3.25).

Answer 16

Correct answer: 0.01

Question 17

Tipranavir is an acidic drug used to treat HIV. If Tipranavir has a KA = 1.10 x 10^-6, how much of the drug would be ionized in the duodenum (pH = 6)? Report your answer to two decimal places (i.e. 3.25).

Answer 17

Correct answer: 52.38

Question 18

Tipranavir is an acidic drug used to treat HIV. If Tipranavir has a KA = 1.10 x 10^-6, how much of the drug would be ionized in the large intestine (pH = 7.8)? Report your answer to two decimal places (i.e. 3.25).

Answer 18

Correct answer: 98.58

Question 19

Tipranavir is an acidic drug used to treat HIV. If Tipranavir has a KA = 1.10 x 10^-6, how much of the drug would be ionized in the blood stream (pH = 7.4)? Report your answer to two decimal places (i.e. 3.25).

Answer 19

Correct answer: 96.51