Question 1

Which property of water allows a spider to walk on the surface of a pond without sinking?

Accepted Answer

Surface tension due to hydrogen bonding

Question 2

Why does ice float on liquid water?

Accepted Answer

Ice is less dense than liquid water because hydrogen bonds keep water molecules farther apart in solid form

Question 3

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

Accepted Answer

Cohesion and adhesion

Question 4

Which of the following best explains why sweating cools the human body?

Accepted Answer

Evaporation of water requires energy, which is taken from the body as heat

Question 5

What is the main reason water is considered the 'universal solvent'?

Accepted Answer

Water’s polarity allows it to dissolve many ionic and polar substances

Question 6

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

Accepted Answer

$$5$$

Question 7

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

Accepted Answer

Buffers minimize changes in pH by accepting or donating H$$^+$$ ions

Question 8

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

Accepted Answer

Water bodies resist rapid temperature changes, stabilizing climates

Question 9

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

Accepted Answer

It increases by a factor of 100

Question 10

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 11

A beaker contains a solution with $$[H^+] = 1 	imes 10$$^{-8}$$ M. What is the pH of this solution, and is it acidic, basic, or neutral?

Accepted Answer

pH = 8; basic

Question 12

Which property of water is most important for the movement of water from the roots to the leaves in tall trees?

Accepted Answer

Cohesion and adhesion

Question 13

Which of the following statements about hydrogen bonds in water is correct?

Accepted Answer

Hydrogen bonds are weak interactions but collectively provide water with unique properties

Question 14

Ocean acidification is primarily caused by which of the following processes?

Accepted Answer

Increased atmospheric CO$$_2$$ dissolving in seawater, forming carbonic acid

Question 15

Which of the following best describes the relationship between the structure of a water molecule and its polarity?

Accepted Answer

The bent shape and difference in electronegativity between O and H make water polar

Question 16

A solution has a pH of 3. What is the concentration of hydrogen ions in this solution?

Accepted Answer

$$1 	imes 10$$^{-3}$$ M

Question 17

Which property of water explains why coastal regions tend to have milder climates than inland regions?

Accepted Answer

High specific heat

Question 18

Which of the following is a hydrophilic substance?

Accepted Answer

Table salt (NaCl)

Question 19

Which of the following equations correctly represents the dissociation of water?

Accepted Answer

$$2H_2O \rightarrow H_3O^+ + OH^-$$

Biological Importance of Water: Properties, Structure, and Function

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