Water & Acid Test Pre- Post Key with sources
Name_________________________________
SC.912.L.18.12 Discuss the special properties of water that contribute to Earth’s
suitability as an environment for life; cohesive behavior, ability to moderate
temperature, expansion upon freezing, and versatility as a solvent.
1. Water is essential for life. Its special properties make water the single most
important molecule in plant life. Which of the following properties of water
enables it to move from the roots to the leaves of plants?
A. Water expands as it freezes.
B. Water is an excellent solvent.
C. Water exhibits cohesive behavior.
D. Water is able to moderate temperature.
Answer:
C. Water exhibits cohesive behavior.
Cohesion means that water molecules are attracted to each other and attracted to other
substances, such as the walls of the xylem of plants. The water molecules behave this
way because they are polar.
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2. Large bodies of water, such as lakes and oceans, do not quickly fluctuate in
temperature. What is the reason for this phenomenon?
A. Water is an acid.
B. Water is a versatile solvent.
C. Water has a high heat capacity.
D. Water acts as a buffer.
Answer
C. Water has a high heat capacity.
Water can absorb a large amount of energy without a large rise in temperature. This is
called heat capacity. As the sun shines on bodies of water, they absorb great amounts of
its energy without a large fluctuation in temperature.
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3. Why does ice stay at the top of oceans instead of sinking to the bottom?
A. Ice is colder than liquid water.
B. Ice is less dense than liquid water.
C. Ice is more dense than liquid water.
D. Ice is warmer than liquid water.
Answers
B. Ice is less dense than liquid water.
As water freezes, its molecules spread apart into a specific arrangement that makes frozen
water less dense than liquid water.
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4. Water is often called the "universal solvent" because many substances can be
dissolved in water. What property of water allows it to be such a versatile
solvent?
A. purity
B. polarity and cohesion
C. high heat capacity
D. expansion upon freezing
Answer
B. polarity and cohesion
Water molecules are polar. This means that they have slight positive and negatively
charged ends. Water molecules are attracted to a wide variety of molecules because of
those charges and thus, acts as a solvent for a variety of compounds.
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5. What gives water many properties that are important to living things?
A.
B.
C.
D.
temperature
hydrogen bonds
density
specific heat
Answer
B. Hydrogen bonds
Hydrogen bond the attraction between the – end of one water molecule to the + end of another
water molecule gives water most of its unique properties; surface tension, cohesion, high specific
heat.
Holt McDougal Biology Florida 2012
6. Which property of water is the result of hydrogen bonds?
A. polarity of water molecules
B. high specific heat
C. low boiling point
D. no cohesion among water molecules
Answer:
B. high specific heat
Water molecules resist the net breaking of hydrogen bonds. Consequently, water resists heating.
Polarity is cause by the unequal sharing of electrons with the covalent bonds between the
Hydrogen and oxygen molecules. Water has a high boiling point and high cohesion among other
water molecules.
Holt McDougal Biology Florida 2012
7. Which substance represented in Figure 2.1 (A or B) is the solvent?
A.
B.
C.
D.
both A and B
substance A
substance B
neither A nor B
Answer:
B. substance A
Substance A is the substance in the greatest concentration thus it is the solvent. B is in lesser
concentration and is the solute.
Holt McDougal Biology Florida 2012
8. When salt is dissolved in water, water is the
A. Reactant
B. Solution
C. Solute
D. Solvent
Answer:
D. Solvent
Water is known as the universal solvent, water does the dissolving the solute is the substance
being dissolved.
SC.912.P.8.11 Relate acidity and basicity to hydronium and hydroxyl
ion concentration and pH.
9. Which of the following solutions has the highest H ion concentration?
A.
B.
C.
D.
a solution with a pH of 1
a solution with a pH of 4
a solution with a pH of 7
a solution with a pH of 10
Answer:
A. A solution with a pH of 1
A low pH indicates a high concentration of hydronium ions, while a high pH indicates a low
concentration.
Holt McDougal Biology Florida 2012
10. How does the addition of an acid affect a neutral solution?
A. The pH is raised.
B. The acid is neutralized.
C. The
ion concentration is increased.
D. The solvent concentration is increased.
Answer:
C. The
ion concentration is increased.
A low pH indicates a high concentration of hydronium ions, while a high pH indicates a low
concentration.
Holt McDougal Biology Florida 2012
11. A solution with a pH of 3 is how many times more acidic than a solution which
has a pH of 9?
A. 6
B. 1,000
C. 100,000
D. 1,000,000
Answer:
D. 1,000,000
The pH scale is logarithmic and as a result, each whole pH value below 7 is ten times
more acidic than the next higher value. The same holds true for pH values above 7, each
of which is ten times more alkaline (another way to say basic) than the next lower whole
value. For example, pH 10 is ten times more alkaline than pH 9 and 100 times (10 times
10) more alkaline than pH 8.
Living in the Environment - Miller
12. A substance with a pH of 6 is called
A. An acid
B. A base
C. Both an acid and a base
D. Neither an acid nor base.
Answer:
A. An Acid
A pH of 1-6 is an acid, a pH of 7 is neutral and 8-14 are basic.
Biology Prentice Hall