Mi vida

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Campbell's Biology, 9e (Reece et al.)
Chapter 3 Water and Life

Life evolved in the ocean, and the chemistry of life occurs in an aqueous environment. These questions explore the properties of water that are important to sustain life’s chemical processes, organismal physiology, and interactions of organisms with their environment. Quantitative properties such as heat content, molarity, andpH are also addressed. A few questions address how human activities affect the global environment through acid rain and acidification of the ocean.

Multiple-Choice Questions

1) In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by
A) hydrogen bonds.
B) nonpolar covalent bonds.
C) polar covalent bonds.
D) ionic bonds.
E) van der Waals interactions.Answer: C
Topic: Concept 3.1
Skill: Knowledge/Comprehension

2) The slight negative charge at one end of one water molecule is attracted to the slight 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 hydrophilic bond
E) a van der Waals interaction
Answer: B
Topic: Concept 3.1
Skill:Knowledge/Comprehension

3) The partial negative charge in a molecule of water occurs because
A) the oxygen atom acquires an additional electron.
B) the electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen atom nucleus than around the hydrogen atom nucleus.
C) the oxygen atom has two pairs of electrons in its valence shell that are not neutralized by hydrogen atoms.
D) theoxygen atom forms hybrid orbitals that distribute electrons unequally around the oxygen nucleus.
E) one of the hydrogen atoms donates an electron to the oxygen atom.
Answer: B
Topic: Concept 3.1
Skill: Knowledge/Comprehension

4) Sulfur is in the same column of the periodic table as oxygen, but has electronegativity similar to carbon. Compared to water molecules, molecules of H2S
A)will ionize more readily.
B) will have greater cohesion to other molecules of H2S.
C) will have a greater tendency to form hydrogen bonds with each other.
D) will have a higher capacity to absorb heat for the same change in temperature.
E) will not form hydrogen bonds with each other.
Answer: E
Topic: Concept 3.1
Skill: Synthesis/Evaluation

5) Water molecules are able to form hydrogenbonds with
A) compounds that have polar covalent bonds.
B) oils.
C) oxygen gas (O2) molecules.
D) chloride ions.
E) any compound that is not soluble in water.
Answer: A
Topic: Concept 3.1
Skill: Application/Analysis

6) Which of the following effects is produced by the high surface tension of water?
A) Lakes don't freeze solid in winter, despite low temperatures.
B) A water stridercan walk across the surface of a small pond.
C) Organisms resist temperature changes, although they give off heat due to chemical reactions.
D) Evaporation of sweat from the skin helps to keep people from overheating.
E) Water flows upward from the roots to the leaves in plants.
Answer: B
Topic: Concept 3.2
Skill: Application/Analysis

7) Which of the following takes place as an ice cubecools a drink?
A) Molecular collisions in the drink increase.
B) Kinetic energy in the drink decreases.
C) A calorie of heat energy is transferred from the ice to the water of the drink.
D) The specific heat of the water in the drink decreases.
E) Evaporation of the water in the drink increases.
Answer: B
Topic: Concept 3.2
Skill: Application/Analysis

8) A dietary Calorie equals 1kilocalorie. Which of the following statements correctly defines 1 kilocalorie?
A) 1,000 calories, or the amount of heat required to raise the temperature of 1 g of water by 1,000°C
B) 100 calories, or the amount of heat required to raise the temperature of 100 g of water by 1°C
C) 10,000 calories, or the amount of heat required to raise the temperature of 1 kg of water by 1°F
D) 1,000...
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