Chapter 3: Water and the Fitness of the Environment

Blueberries grow best in moderately acidic soil. What is an appropriate pH of a soil that is good for blueberries?
1. 1.2
2. 4.8
3. 7.0
4. 8.3
5. 12.0
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?
1. a covalent bond
2. a hydrogen bond
3. an ionic bond
4. a hydration shell
5. a hydrophobic bond
Which bonds must be broken for water to vaporize?
1. ionic bonds
2. non polar covalent bonds
3. polar covalent bonds
4. hydrogen bonds
5. ionic and polar covalent bonds
Which of the following liquids does NOT have a measureable pH?
1. milk
2. sea water
3. gasoline
4. orange juice
5. distilled water
Life on Earth is dependent 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?
1. cohesion and high surface tension
2. high specific heat
3. high heat of vaporization
4. expansion upon freezing
5. versatility as a solvent
Which of the following is an example of a hydrogen bond?
1. the bond between C and H in methane
2. the bond between the H of one water molecule and the O of another water molecule
3. the bond between Na and Cl in salt
4. the bond between two hydrogen atoms
5. the bond between Mg and Cl in MgCl2
Which of the following solutions has the greater concentration of hydrogen ions (H+).
1. gastric juice at pH 2
2. vinegar at pH 3
3. tomatoes at pH 4
4. black coffee at pH 5
5. seawater at pH 8
Which of the following solutions has the greater concentration of hydroxyl ions (OH^-)?
1. gastric juice at pH 2
2. vinegar at pH 3
3. tomatoes at pH 4
4. black coffee at pH 5
5. seawater at pH 8
A solution with a pH of 3 has how many more H⁺ than a solution with a pH of 6?
1. 2 times more
2. 10 times more
3. 100 times more
4. 200 times more
5. 1000 times more
What would be the pH of a solution with a hydroxyl ion concentration of 10-10M?
1. 2
2. 4
3. 8
4. 10
5. 14
Buffers are substances that help resist shifts in pH by
1. releasing H⁺ in acidic solutions.
2. releasing H⁺ in basic solutions.
3. combining with H⁺ in basic solutions
4. combining with OH^- in acidic solutions.
5. releasing OH^- in basic solutions.
Which of the following statements about water is CORRECT?
1. Water is more dense as a solid than it is as a liquid.
2. Water is more dense at 100 degrees C than it is at 37 degrees C.
3. Water is a good solvent for lipids.
4. Compared to most other substances, the temperature of water rises sharply when it absorbs heat.
5. Compared to most liquids, the evaporation of water requires a large amount of heat.
What do the following have in common with reference to water: cohesion, surface tension, specific heat?
1. All are products of the structure of the hydrogen atom.
2. All are produced by covalent bonding.
3. All are properties related to hydrogen bonding.
4. All have to do with polarity of water molecules.
5. All are aspects of a semicrytalline structure.
Assume that acid rain has lowered the pH of a particular lake to pH 5.0. What is the hydroxide ion concentration of this lake?
1. 1 x 10(-5th) moles of hydroxide ion per liter of lake water
2. 1 x 10 (-9th) moles of hydroxide ion per liter of lake water
3. 5.0 molar with regard to hydroxide ion concentration
  5.0 molar with regard to hydroxide ion concentration
4. 9.0 molar with regard to hydroxide ion concentration
5. Both B and D are correct
The nutritional information on a cereal box shows that one serving of dry cereal has 90 calories (actually kilocalories). If one were to burn a serving of cereal, the amount of heat given off would be sufficient to raise the temperature of one kilogram of water how many degree Celsius?
1. 0.9 Celsius
2. 9.0 Celsius
3. 90.0 Celsius
4. 900.0 Celsius
5. 9000.0 Celsius
The formation of ice during colder weather helps to temper the seasonal transition to winter. This is mainly because
1. the formation of hydrogen bonds releases heat.
2. the formation of hydrogen bonds absorbs heat.
3. there is less evaporative cooling of lakes.
4. ice melts each autumn afternoon
5. ice is warmer than the winter air
What bonds must be broken for water to go from a liquid to a gas?
1. covalent
2. polar covalent
3. ionic
4. hydrogen
5. hydrophobic
Water's high specific heat is mainly a consequence of the
1. small size of the water molecules
2. high specific heat of oxygen and hydrogen atoms
3. absorption and release of heat when hydrogen bonds break and form
4. fact that water is poor heat conductor
5. inability of water to dissipate heat into dry air
The molecular mass of glucose is 180 g. To make a one-molar solution of glucose, you should do which of the following?
1. Dissolve 100 g of glucose in a liter of water
2. Dissolve 180 g of glucose in a gallon of water.
3. Dissolve 180 g of glucose in 100 grams of water
4. Dissolve 180 mg of glucose in one liter of water
5. Dissolve 180 g of glucose in water, and then add more water until the total volume of the solution is one liter.
How many grams of ethanoic acid (carboxylic acid) should one add to a liter of water to make a 0.2 M solution?
1. 8
2. 12
3. 24
4. 32
5. 60
Which of the following ionizes completely in solution and is there fore a strong acid?
1. NaOH
2. H₂CO₃
3. CH₃COOH
4. NH₂
5. HCl
Ice is lighter and floats in water because it is a crystalline structure held together by
1. ionic bonds only
2. hydrogen bonds only
3. covalent bonds only
4. both ionic and hydrogen bonds
5. both ionic and covalent bonds
Assuming a temperature of 25 degrees Celsius, what does a pH of 7 indicate?
1. The solution is neutral
2. The concentration of H⁺ ions is 10 -7th moles per liter
3. There are no H⁺ ions in the solution
4. There are no OH^- ions in the solution
5. Both A and B are correct
When water is vaporized, what occurs? It is
1. oxidized
2. reduced
3. decreased in the number of H⁺
4. destabilized and hydrogen bonds
5. disrupted and its density decreases
What determines the cohesiveness of water molecules?
1. hydrophobic interactions
2. high specific heat
3. covalent bonds
4. hydrogen bonds
5. ionic bonds
It is correct to say that the action of buffers
1. is of relatively little significance in living organisms.
2. tends to prevent great fluctuations in pH
3. depends on the formation of a great number of hydrogen ions
4. depends on the presence of many electron donors
5. is to remove hydroxyl ions from organic acids
If the pH of a solution is decreased from 7 to 6, it means that the
1. concentration of H⁺ has decreased to 1/10 of what it was at pH 7
2. concentration of H⁺ has increased to 10 times what it was at pH 7
3. concentration of OH^- has increased to 10 times what it was at pH 7
4. concentration of OH^- has increased by 1/7 of what it was
5. solution has become more basic
The following question refers to the terms below.
A. calorie
B. temperature
C. heat of vaporization
D. buffer
E. mole

A measurement of the average kinetic energy of the molecules in a body of matter is the
1. A
2. B
3. C
4. D
5. E
The following question refers to the terms below.
A. calorie
B. temperature
C. heat of vaporization
D. buffer
E. mole

The number of grams of a substance that equals its molecular mass in Daltons is
1. A.
2. B.
3. C.
4. D.
5. E.
The following question refers to the terms below.
A. calorie
B. temperature
C. heat of vaporization
D. buffer
E. mole

A weak acid or base that combines reversibly with hydrogen ions is a
1. A.
2. B.
3. C.
4. D.
5. E.
Which of the following is a CORRECT definition of a kilocalorie?
1. the amount of heat energy required to raise 1 gram of water by one degree Fahrenheit
2. the amount of heat energy required to raise one gram of water by ten degrees Celsius
3. the amount of heat energy required to raise one kilogram of water by one degree Celsius
4. a measure of the average kinetic energy of a pint of water
5. the amount of energy in one kilogram of glucose
At what temperature is water at its densest?
1. 0 degrees Celsius
2. 4 degrees Celsius
3. 32 degrees Celsius
4. 100 degrees Celsius
5. 212 degrees Celsius
Temperature usually increases when water condenses. Which behavior of water is most directly responsible for this phenomenon?
1. Change in density when it condenses to form a liquid or solid
2. reactions with other atmospheric compounds
3. release of heat by formation of hydrogen bonds
4. release of heat by breaking of hydrogen bonds
5. high surface tension
Water is able to form hydrogen bonds because
1. All of the below are correct
2. the water molecule is shaped something like a right angle
3. the water molecule is polar
4. the oxygen atom in a water molecule is weakly negative
5. the hydrogen atoms in a water molecule are weakly positive
Why does ice float in liquid water?
1. The liquid water molecules have more energy and can push the ice up.
2. The hydrogen bonds between the molecules in ice prevent the ice from sinking.
3. Ice always has air bubbles that keep it a float
4. Hydrogen bonds keep the molecules of ice farther apart than in liquid water.
5. The crystalline lattice of ice causes it to be denser than liquid water.
What is the maximum number of hydrogen bonds a water molecule can form with neighboring water molecules?
1. 1
2. 2
3. 3
4. 4
5. 5
Water is transported in plant tissue against gravity due to which of the following properties?
1. cohesion
2. adhesion
3. hydrogen bonding
4. surface tension
5. All but D
Which of the following is possible due to the surface tension of water?
1. Lakes don't freeze solid in the winter, despite low temperatures
2. A Water Strider can walk across a small pond.
3. Organisms resist temperature changes though they give off heat due to chemical reactions
4. Water is said to be the solvent of life
5. The pH of pure water is near neutral
Why are aquatic systems most sensitive to acid precipitation in the spring?
1. Spring snow melts contain acid collected all winter
2. Eggs and young are developing during spring
3. Snow below the surface melts first
4. Young and eggs are especially vulnerable to low pH levels.
5. All of the above except C
Recent research indicates that acid rain can damage life by
1. buffering aquatic systems
2. decreasing the H+ concentration
3. changing the solubility of soil minerals
4. breaking the molecules of living organisms
5. Both C and D are true