Question 1

Which property of water explains why ice floats on liquid water, providing a habitat for animals such as seals in the Arctic?

Accepted Answer

Solid water is less dense than liquid water due to hydrogen bonding.

Question 2

Why does sweating help cool the human body during exercise?

Accepted Answer

Evaporation of sweat absorbs heat due to water’s high heat of vaporization.

Question 3

Which equation correctly represents the dissociation of water?

Accepted Answer

$$ \mathrm{H_2O} \rightleftharpoons \mathrm{H^+} + \mathrm{OH^-} $$

Question 4

A solution has a hydrogen ion concentration of $$1 	imes 10$$^{-5}$$ M. What is its pH?

Accepted Answer

$$ \mathrm{pH} = 5 $$

Question 5

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

Accepted Answer

Water molecules are polar and form hydration shells around ions.

Question 6

What is the main function of buffers in biological systems?

Accepted Answer

To maintain a constant pH by minimizing changes in $$[\mathrm{H^+}]$$ and $$[\mathrm{OH^-}].$$

Question 7

Which of the following is a real-world consequence of acid precipitation caused by burning fossil fuels?

Accepted Answer

Changes in soil chemistry that harm aquatic and land plants.

Question 8

Why do coastal areas tend to have more stable temperatures than inland areas?

Accepted Answer

Water has a high specific heat, absorbing and releasing heat slowly.

Question 9

Which of the following best explains why oil does not dissolve in water?

Accepted Answer

Oil molecules are nonpolar and cannot form hydrogen bonds with water.

Question 10

A patient’s blood pH drops from 7.4 to 7.0. What is the likely consequence?

Accepted Answer

The patient may not survive, as blood pH below 7.0 is fatal.

Question 11

Which of the following equations correctly represents the action of the carbonic acid buffer system in blood?

Accepted Answer

$$ \mathrm{H_2CO_3} \rightleftharpoons \mathrm{HCO_3^-} + \mathrm{H^+} $$

Question 12

Which property of water allows trees to transport water from their roots to their leaves?

Accepted Answer

Cohesion and adhesion due to hydrogen bonding

Question 13

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

Accepted Answer

It increases by a factor of 100.

Question 14

Which of the following best describes the difference between cohesion and adhesion in water?

Accepted Answer

Cohesion is water’s attraction to itself; adhesion is water’s attraction to other substances.

Question 15

Which of the following is a direct result of water’s high surface tension?

Accepted Answer

Some insects can walk on the surface of water.

Question 16

Which of the following best explains why ocean acidification is harmful to marine life?

Accepted Answer

It lowers the pH, affecting organisms that rely on carbonate ions for shells and skeletons.

Question 17

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

Accepted Answer

Acids donate protons ($$\mathrm{H^+}$$); bases accept protons or donate $$\mathrm{OH^-}.$$

Question 18

A solution has a pH of 8. Which of the following best describes this solution?

Accepted Answer

It is basic.

Question 19

Which of the following is a consequence if ice were more dense than liquid water?

Accepted Answer

Ice would sink, causing bodies of water to freeze solid from the bottom up.

Question 20

Which of the following best describes a hydrophilic substance?

Accepted Answer

It has an affinity for water and is dominated by ionic or polar bonds.

Water and Life: Properties, Acids, and Bases

Study Guide - Practice Questions