$$M = \frac{2\ \text{mol}}{1\ \text{L}} = 2\ \text{M}$$

Question 1

Which property of water allows ice to float on liquid water, and why is this important for aquatic life?

Accepted Answer

Water's expansion upon freezing; ice is less dense than liquid water, insulating aquatic environments.

Question 2

What type of bond forms between the hydrogen atom of one water molecule and the oxygen atom of another water molecule?

Accepted Answer

Hydrogen bond

Question 3

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

Accepted Answer

Because hydrogen bonds between water molecules absorb and release heat slowly.

Question 4

A solution has a pH of 7. If the concentration of $$[H^+]$$ increases by a factor of 100, what is the new pH?

Accepted Answer

5

Question 5

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

Accepted Answer

Water molecules are polar and can surround and separate ions due to their partial charges.

Question 6

Which property of water is most directly responsible for the movement of water from roots to leaves in plants?

Accepted Answer

Cohesion and adhesion

Question 7

What is the molarity ($$M) of a $$solution containing 2 moles of NaCl dissolved in 1 liter of water?

Accepted Answer

$$M = \frac{2\ 	ext{mol}}{1\ 	ext{L}} = 2\ 	ext{M}$$

Question 8

Which of the following substances is most likely to be hydrophobic?

Accepted Answer

Olive oil

Question 9

If a solution has $$[H^+] = 1 	imes 10$$^{-4}$$, what is its pH?

Accepted Answer

pH = 4

Question 10

Which statement best describes the polarity of a water molecule?

Accepted Answer

The oxygen atom has a partial negative charge and the hydrogen atoms have partial positive charges.

Question 11

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

Accepted Answer

Bodies of water would freeze from the bottom up, threatening aquatic life.

Question 12

A hydronium ion ($$H_3O^+) $$forms when:

Accepted Answer

A water molecule gains a proton ($$H^+) $$from another water molecule.

Question 13

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

Accepted Answer

$$pH = -\log [H^+]$$

Question 14

Which property of water is most important for maintaining stable temperatures in lakes and oceans?

Accepted Answer

High specific heat

Question 15

A solution of pH 8 is made 1,000 times more acidic. What is the new pH?

Accepted Answer

4

Question 16

Which of the following best describes surface tension in water?

Accepted Answer

It is a measure of how difficult it is to break the surface of a liquid due to hydrogen bonding.

Question 17

Which of the following is NOT an emergent property of water that contributes to Earth's suitability for life?

Accepted Answer

High reactivity with nonpolar molecules

Question 18

What is the molecular mass of $$H_2O$$? (Atomic masses: H = 1, O = 16)

Accepted Answer

$$1 	imes 2 + 16 = 18$$

Question 19

Which of the following best describes an acid in aqueous solution?

Accepted Answer

A substance that increases $$[H^+]$$ concentration.

Question 20

Which of the following is true about hydrophilic substances?

Accepted Answer

They have an affinity for water and are usually ionic or polar.

Water and Life: Properties and Importance of Water in Biology

Study Guide - Practice Questions