Question 1

Which property of water is primarily responsible for the ability of some insects, such as water striders, to walk on the surface of a pond without sinking?

Accepted Answer

Surface tension due to hydrogen bonding

Question 2

A plant is able to transport water from its roots to its leaves against gravity. Which combination of water’s properties is most directly responsible for this phenomenon?

Accepted Answer

Cohesion and adhesion

Question 3

Why does ice float on liquid water, and what would be the consequence for aquatic life if it did not?

Accepted Answer

Ice is less dense than liquid water because hydrogen bonds are more ordered, so it floats, insulating aquatic life below.

Question 4

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

Accepted Answer

Water molecules are polar and form hydration shells around ions.

Question 5

A solution has a hydrogen ion concentration of $$[H^+] = 1 	imes 10$$^{-5}$$ M. What is the pH of this solution?

Accepted Answer

$$pH = 5$$

Question 6

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

Accepted Answer

A base decreases the $$[H^+]$$ concentration of a solution.

Question 7

If the pH of a solution changes from 6 to 4, what happens to the hydrogen ion concentration?

Accepted Answer

It increases by 100-fold.

Question 8

Which of the following best describes the role of buffers in biological systems?

Accepted Answer

Buffers minimize changes in $$[H^+]$$ and $$[OH^-]$$ concentrations.

Question 9

Ocean acidification is primarily caused by which process?

Accepted Answer

Absorption of $$CO_2 by $$the oceans, forming carbonic acid

Question 10

Which of the following equations correctly represents the relationship between hydrogen ion and hydroxide ion concentrations in pure water at 25°C?

Accepted Answer

$$[H^+][OH^-] = 10$$^{-14}$$

Question 11

A beaker contains a solution with a pH of 8. Which of the following best describes this solution?

Accepted Answer

It is basic, with a low $$[H^+]$$ concentration.

Question 12

Which of the following real-life scenarios best illustrates evaporative cooling?

Accepted Answer

Sweating during exercise, which cools the body as sweat evaporates

Question 13

Why does water have a high specific heat compared to most other substances?

Accepted Answer

Because hydrogen bonds must absorb heat to break and release heat when they form

Question 14

Which of the following best explains why oil does not mix with water?

Accepted Answer

Oil molecules are hydrophobic due to their nonpolar bonds.

Question 15

A scientist adds a strong acid to a buffered solution. What is the most likely outcome?

Accepted Answer

The buffer will minimize the change in pH.

Question 16

Which of the following is a direct consequence of water’s ability to form hydrogen bonds?

Accepted Answer

Water has a high surface tension.

Question 17

A solution contains $$[OH^-] = 1 	imes 10$$^{-9}$$ M. What is the pH of this solution?

Accepted Answer

Question 18

Which of the following best describes the molecular structure of water?

Accepted Answer

Water is a polar molecule with an uneven charge distribution.

Question 19

Which of the following is an example of water’s ability to moderate temperature in a real-world context?

Accepted Answer

The Pacific Ocean keeping coastal cities cooler in summer and warmer in winter

Water and Life: Properties and Biological Importance

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