1. A hydrogen bond donor is typically
a. a highly electronegative atom with an unshared pair of electrons.
b. none of these choices
c. a weakly electronegative atom covalently bonded to a hydrogen.
d. a weakly electronegative atom with an unshared pair of electrons.
e. a highly electronegative atom covalently bonded to a hydrogen.
2. Which of the following statements about water is false?
a. The H-O-H bond angle is 105º.
b. Water can serve as both a donor and an acceptor in hydrogen bond formation.
c. The arrangement of hydrogen bonds as a highly ordered three-dimensional network is more stable in liquid
water than it is in ice.
d. Water has a dipole, in part, due to its bent shape.
e. The maximum density of water is found in the liquid state.
3. The average lifetime of hydrogen bonds between water molecules is about how long?
a. 10-8 seconds
b. 10-10 seconds
c. 10-6 seconds
d. 10 seconds
e. 10 minutes
4. The interactions between nonpolar molecules in water are called
a. ionic interactions.
b. hydrophobic interactions.
c. hydrogen bonds.
d. colligative interactions.
e. hydrophilic interactions.
5. Amphipathic compounds
a. have both positive and negative portions.
b. cannot participate in hydrogen bonds.
c. have both acidic and basic portions.
d. have both polar and nonpolar portions.
e. are strongly ionic.
6. Bonds with negative and positive ends are called
a. electronegative.
b. dipoles.
c. amphipathic.
d. van der Waals bonds.
e. zwitterions.
7. Water is ineffective as a solvent of
a. none of these choices
b. ionic compounds.
c. nonpolar compounds.
d. polar compounds.
e. all of these choices
8. Hydrogen bonds have a vital involvement in stabilizing the three dimensional structures of which of the following
biologically important molecules?
a. RNA
b. DNA
c. none of these choices
d. all of these choices
e. proteins
9. A biologically useful definition of a base is
a. a molecule that acts as a proton (hydrogen ion) donor.
b. a molecule that has both positive and negative ends.
c. a molecule that forms micelles in water.
d. a molecule that hydrogen bonds well with water.
e. a molecule that acts as a proton (hydrogen ion) acceptor.
10. The constant Kw, the ion product of water, can be written as:
a. Kw = [H+][OH-] = 10-14
b. Kw = [H+][OH-] = 10-7
c. Kw = [H+][OH-] = 1014
d. none of these choices
e. Kw = [H+][OH-] = 10-12
11. If the pH of a solution is 7, then the concentration of hydrogen ions in that solution is:
a. none of these choices
b. 107
c. 10-7
d. 10-14
e. 1014
12. pH = pKa + log [A-]/[HA]:
a. all of these choices
b. is known as the Henderson-Hasselbalch equation.
c. contains [A-], which represents a weak acid's conjugate base.
d. allows the pH of a solution composed of a weak electrolyte to be calculated.
e. is useful in predicting the properties of buffer solutions.
13. Which of the following statements is true?
a. The lower the Ka, the stronger the acid.
b. The greater the Ka, the higher the melting point.
c. The greater the Ka, the greater the ability to form micelles.
d. The greater the Ka, the stronger the acid.
e. The greater the Ka, the greater the solubility in water.
14. When the pH of a solution is greater than the pKa of an acid,
a. the deprotonated form predominates.
b. the acid decomposes.
c. the protonated form predominates.
d. the protonated and deprotonated forms exist at equal concentrations.
e. the acid absorbs all the protons in solution.
15. Phosphoric acid, H3PO4, serves to buffer the intracellular fluid of cells at physiological pH because:
a. phosphate is only found in an organic form in biological molecules.
b. its pK1 lies near the physiological pH value of the cell
c. it is a naturally occurring amino acid.
d. none of these choices
e. its pK2 lies near the physiological pH value of the cell
16. Which of the following statements is true?
a. The greater the pKa, the stronger the acid.
b. The greater the pKa, the greater the solubility in water.
c. The lower the pKa, the stronger the acid.
d. The greater the pKa, the greater the ability to form micelles.
e. The greater the pKa, the higher the melting point.
17. Which of the following statements concerning the bicarbonate buffer system of blood plasma is true?
a. HCO3- reacts with water to form H2PO4, which has a pKa close to the pH of blood.
b. H2CO3 in the blood dissociates to form HCO3-.
c. H2CO3 in the blood dissociates to form HCO3- and dissolved CO2 in the blood forms H2CO3.
d. Dissolved CO2 in the blood forms H2CO3.
e. H2CO3 in the blood dissociates to form HCO3- and HCO3- reacts with water to form H2PO4, which has a pKa
close to the pH of blood.
18. Which of the following is true about buffer systems?
a. They are typically made up of a strong acid and a strong base mixed together.
b. None of these choices is true.
c. They will have an area on their titration curve where the greatest buffering capacity exists.
d. The pH will vary greatly in the region of the titration curve where [HA] = [A -].
e. They will vary greatly in pH as acid or base is added.
19. The point in a titration at which the acid is exactly neutralized is called the
a. buffering capacity.
b. Henderson-Hasselbalch point.
c. crystallization point.
d. equivalence point.
e. Kw.
20. A buffer of HPO42-/H2PO4- has a pH of 7.4. What is the ratio of HPO42-/H2PO4- in this buffer?
a. 2 x 10-3
b. 0.62
c. 1.6
d. 1 x 10-14
e. 7.0
21. The pH of a solution with a hydroxyl ion concentration of 4 x 10-3 is:
a. 12.6
b. 3.6
c. 2.4
d. 10.4
e. 11.6
22. Zwitterions are
a. compounds that form micelles.
b. compounds that have both positive and negative charges.
c. polyprotic acids.
d. compounds with low pKas.
e. weak buffers.
23.
Hydrocarbons are usually
a. ions.
b. nonpolar.
c. amphipathic.
d. polar.
e. polyprotic acids.
24. Hydrogen bonds are usually
a. good buffers.
b. found in hydrocarbons.
c. weaker than van der Waals interactions.
d. linear.
e. stronger than covalent bonds.
25. Which of the following would make a good buffer for a pH between 4 and 5?
a. pyruvic acid (pKa = 2.50).
b. ammonium ion (pKa = 9.25).
c. phosphoric acid (pKa1 = 2.14, pKa2 = 7.2, pKa3 = 12.40).
d. Cannot be determined from the information provided.
e. acetic acid (pKa = 4.76).