General ---------Biology ------------------Online------------------------ Ch.  3:  Water and the fitness of the environment

Ch. 3 Practice Quiz (23 questions).  

1. Blueberries grow best in moderately acidic soil. What is an
     appropriate pH of a soil that is good for blueberries?
     a. 1.2
     b. 4.8
     c. 7.0
     d. 8.3
     e. 12.0

2. The partial negative charge at one end of a water molecule is
     attracted to the partial positive charge of another water molecule.
     What is this attraction called?
     a. a covalent bond
     b. a hydrogen bond
     c. an ionic bond
     d. a hydration shell
     e. a hydrophobic bond

3. Which bonds must be broken for water to vaporize?
     a. ionic bonds
     b. nonpolar covalent bonds
     c. polar covalent bonds
     d. hydrogen bonds
     e. Both polar covalent bonds and hydrogen bonds are correct.

4. Life on earth is dependant on all the properties of water as well as
     the abundance of water. Which property of water is probably most
     important for the functioning of organisms at the molecular level?
     a. cohesion and high surface tension
     b. high specific heat
     c. high heat of vaporization
     d. expansion upon freezing
     e. versatility as a solvent

5. Which of the following is an example of a hydrogen bond?
     a. the bond between C and H in methane
     b. the attraction between the H of one water molecule and the O of
        another water molecule
     c. the bond between Na and Cl in salt
     d. the bond between two hydrogen atoms
     e. the bond between Mg and Cl in MgCl2

6. Which of the following solutions has the greater concentration of
     hydrogen ions (H+)?
     a. gastric juice at pH 2
     b. vinegar at pH 3
     c. tomatoes at pH 4
     d. black coffee at pH 5
     e. seawater at pH 8

7. Which of the following statements about water is correct?
     a. Water is more dense as a solid than it is as a liquid.
     b. Water is less dense as ice than it is as liquid.
     c. Water is a good solvent for lipids.
     d. Compared to most other substances, the temperature of water rises
        sharply when it absorbs heat.
     e. Compared to most liquids, the evaporation of water requires very
         little heat.

8. What do the following have in common with reference to water:
     cohesion, surface tension, specific heat?
     a. All are products of the structure of the hydrogen atom.
     b. All are produced by covalent bonding.
     c. All are properties related to hydrogen bonding.
     d. All have to do with polarity of water molecules.
     e. All are aspects of a semi-crystalline structure.

9. The formation of ice during colder weather helps to temper the
     seasonal transition to winter. This is mainly because
     a. the formation of hydrogen bonds releases heat.
     b. the formation of hydrogen bonds absorbs heat.
     c. there is less evaporative cooling of lakes.
     d. ice melts each autumn afternoon.
     e. ice is warmer than the winter air.

10. Water's high specific heat is mainly a consequence of the
     a. small size of the water molecules.
     b. high specific heat of oxygen and hydrogen atoms.
     c. absorption and release of heat when hydrogen bonds break and
        form.
     d. fact that water is a poor heat conductor.
     e. inability of water to dissipate heat into dry air.

11. This question is based on the diagram of a solute molecule (Figure
     3.1) surrounded by a shell of water.  The small circles in the
     diagram depict the oxygen of the water. The solute molecule is most
     likely 

a. positively charged. b. negatively charged.  c. neutral in charge. d. hydrophobic. e. polar.

12. The molecular mass of glucose is 180g. To make a one-molar solution
     of glucose, you should do which of the following?
     a. Dissolve 100g of glucose in a liter of water.
     b. Dissolve 180g of glucose in a gallon of water.
     c. Dissolve 180g of glucose in 100 grams of water.
     d. Dissolve 180mg (milligrams) of glucose in one liter of water.
     e. Dissolve 180g of glucose in water, and then add more water until
        the total volume of the solution is one liter.

13. Ice is lighter and floats in water because it is a crystalline
     structure held together by
     a. ionic bonds only.
     b. hydrogen bonds only.
     c. covalent bonds only.
     d. both ionic and hydrogen bonds.
     e. both ionic and covalent bonds.

14. What does the energy to vaporize water do?
     a. oxidizes the water
     b. reduces (adds electrons to) the water molecules
     c. decreases the number of hydrogen ions (H +) in water
     d. breaks hydrogen bonds between water molecules
     e. decreases the density of water

15. What determines the cohesiveness of water molecules?
     a. hydrophobic interactions
     b. high specific heat
     c. covalent bonds
     d. hydrogen bonds
     e. ionic bonds

16. All of the following are true statements concerning hydrogen bonding
     EXCEPT
     a. In H-bonds, the hydrogen atom is also involved in a polar
        covalent bond.
     b. H-bonds are responsible for the cohesive properties of water.
     c. H-bonds are among the strongest of all chemical bonds.
     d. H-bonds are rapidly formed and rapidly broken.
     e. Large numbers of H-bonds confer considerable stability to a group
        of molecules.

17. What do cohesion, surface tension, and adhesion have in common with
     reference to water?
     a. All increase when temperature increases.
     b. All are produced by covalent bonding.
     c. All are properties related to hydrogen bonding.
     d. All have to do with nonpolar covalent bonds.
     e. All increase when temperature increases and all are properties
        related to hydrogen bonding.

18. A measure of the average kinetic energy of the molecules in a
     body of matter.
          a. calorie
           b. temperature
           c. heat of vaporization
           d. buffer
           e. mole 

19. A weak acid or base that combines reversibly with hydrogen ions.
          a. calorie
           b. temperature
           c. heat of vaporization
           d. buffer
           e. mole
20. At what temperature is water at its densest?
     a. 0C
     b. 4C
     c. 32C
     d. 100C
     e. 212C

21. Temperature usually increases when water condenses. Which behavior
     of water is most directly responsible for this phenomenon?
     a. change in density when it condenses to form a liquid or solid
     b. reactions with other atmospheric compounds
     c. release of heat by formation of hydrogen bonds
     d. release of heat by breaking of hydrogen bonds
     e. high surface tension

22. Water is able to form hydrogen bonds because
     a. All of these are correct.
     b. the water molecule is shaped something like a right angle.
     c. the water molecule is polar.
     d. the oxygen atom in a water molecule is weakly negative.
     e. the hydrogen atoms in a water molecule are weakly positive.

23. If liquid water molecules are hydrogen-bonded to one another, why is
     it that water flows?
     a. The hydrogen bonds in liquid water are weaker than those in ice.
     b. Hydrogen bonds form very slowly in the temperature range of
        liquid water.
     c. In liquid water, the hydrogen bonds bend more easily than they do
        in ice.
     d. The hydrogen bonds in liquid water are constantly breaking and
        reforming.
     e. Only a few of the liquid water molecules actually form hydrogen
        bonds.