Question 1

In a water molecule, which atom do the electrons of the polar covalent bonds spend more time near, and why?

Accepted Answer

Oxygen, because it has a higher electronegativity than hydrogen.

Question 2

Which emergent property of water is primarily responsible for the movement of water up plant stems against gravity?

Accepted Answer

Cohesion and adhesion

Question 3

Why does ice float on liquid water, and how does this benefit aquatic life in cold climates?

Accepted Answer

Ice is less dense than liquid water, so it floats and insulates the water below.

Question 4

Which property of water allows it to absorb and release large amounts of heat with only a slight change in its own temperature?

Accepted Answer

High specific heat

Question 5

A solution has a pH of 5. Which of the following statements is correct?

Accepted Answer

The solution is acidic and has a high concentration of H$$^+.$$

Question 6

Which equation correctly represents the relationship between pH and hydrogen ion concentration?

Accepted Answer

$$\mathrm{pH} = -\log_{10}[\mathrm{H}^+]$$

Question 7

Which of the following best describes a buffer in biological systems?

Accepted Answer

A buffer minimizes changes in pH by accepting or donating H$$^+$$ ions.

Question 8

If the pH of human blood drops from 7.4 to 7.1, how would the carbonic acid buffer system respond?

Accepted Answer

It would absorb H$$^+$$ ions to raise the pH back toward 7.4.

Question 9

Which of the following molecules is most likely to dissolve in water?

Accepted Answer

A polar molecule such as glucose

Question 10

Which property of water is most important for evaporative cooling in living organisms?

Accepted Answer

High heat of vaporization

Question 11

Which of the following best explains why water is an excellent solvent for ionic compounds?

Accepted Answer

Water's polarity allows it to surround and separate ions.

Question 12

Which of the following is an example of water's adhesive property?

Accepted Answer

Water molecules sticking to the walls of a plant's xylem

Question 13

Which of the following best describes the difference between a solute and a solvent?

Accepted Answer

A solute is the substance that dissolves, and a solvent is the substance that does the dissolving.

Question 14

Which of the following best defines specific heat?

Accepted Answer

The amount of heat required to raise the temperature of 1 gram of a substance by 1 degree Celsius.

Question 15

Which of the following is a consequence of water's high specific heat for living organisms?

Accepted Answer

Stable internal and external temperatures

Question 16

Which of the following best describes the process of evaporative cooling?

Accepted Answer

Heat is absorbed when water molecules evaporate, cooling the surface.

Question 17

Which of the following statements about acids and bases is correct?

Accepted Answer

Bases decrease the concentration of H$$^+$$ ions in solution.

Question 18

A student mixes salt (NaCl) in water. Which of the following best describes the resulting mixture?

Accepted Answer

Water is the solvent and salt is the solute.

Question 19

Which of the following best describes thermal energy?

Accepted Answer

The total kinetic energy of all particles in a substance.

Question 20

Which of the following is a real-world example of water's cohesive property?

Accepted Answer

Water droplets forming beads on a car after rain

Ch 3 Outline Water: Structure, Properties, and Its Role in Biological Systems

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