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?

Accepted Answer

Surface tension due to cohesion

Question 2

Water is described as a polar molecule. What does this mean in terms of its atomic structure?

Accepted Answer

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

Question 3

Which equation correctly defines pH in terms of hydrogen ion concentration?

Accepted Answer

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

Question 4

Why does ice float on liquid water?

Accepted Answer

Ice is less dense than liquid water because hydrogen bonds stabilize a more open structure

Question 5

A coastal city experiences milder temperature fluctuations than an inland city at the same latitude. Which property of water explains this phenomenon?

Accepted Answer

Water's high specific heat

Question 6

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

Accepted Answer

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

Question 7

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

Accepted Answer

Water exhibits cohesion and adhesion

Question 8

A solution has a hydrogen ion concentration of $1 	imes 10^{-4}$ M. What is its pH?

Accepted Answer

$4$

Question 9

Which statement best explains why water is an excellent solvent for many biological molecules?

Accepted Answer

Water's polarity enables it to surround and interact with charged and polar molecules

Question 10

Which of the following scenarios demonstrates water's adhesive property?

Accepted Answer

Water climbing up the walls of a plant's xylem vessels

Question 11

If the concentration of $[\mathrm{H}^+]$ in a solution is $1 	imes 10^{-8}$ M, what is the $[\mathrm{OH}^-]$ concentration at $25^\circ$C?

Question 12

Which of the following best describes the difference between heat and temperature?

Accepted Answer

Heat is the total kinetic energy of molecules; temperature is the average kinetic energy

Question 13

Which property of water is most important for the survival of aquatic organisms during winter?

Accepted Answer

Water's expansion upon freezing

Question 14

A scientist finds a planet with evidence of liquid water. Why is this significant in the search for extraterrestrial life?

Accepted Answer

Life on Earth is based on water, so liquid water may support life elsewhere

Question 15

Which of the following best explains why water resists changes in temperature?

Accepted Answer

Water has a high specific heat due to hydrogen bonding

Question 16

Which of the following is NOT a property of water that facilitates an environment for life?

Accepted Answer

Low specific heat

Question 17

Which of the following molecules would most likely dissolve in water?

Accepted Answer

A polar molecule with ionized regions

Question 18

If a solution has a pH of 5, which of the following statements is true?

Accepted Answer

The solution is acidic and has more $[\mathrm{H}^+]$ than $[\mathrm{OH}^-]$

Question 19

Which process occurs when water molecules absorb heat and hydrogen bonds break?

Accepted Answer

Water evaporates

Question 20

Which of the following best describes the dynamic equilibrium of water molecules in a closed system?

Accepted Answer

The rate of water molecule formation equals the rate of their breakdown

Water: Properties, Structure, and Biological Importance

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