Question 1

Which property of water allows insects like water striders to walk on its surface, and what molecular interaction is responsible for this phenomenon?

Accepted Answer

Cohesion; hydrogen bonds between water molecules

Question 2

Why does ice float on liquid water, and what is the underlying molecular reason for this behavior?

Accepted Answer

Ice is less dense than liquid water because hydrogen bonds in ice create more space between molecules

Question 3

A solution is made by dissolving table salt (NaCl) in water. Which term best describes NaCl in this scenario, and why does it dissolve?

Accepted Answer

Solute; because NaCl is hydrophilic and can interact with water's polar regions

Question 4

Which of the following best explains why water has a high specific heat capacity?

Accepted Answer

Hydrogen bonds between water molecules absorb heat energy before breaking, stabilizing temperature

Question 5

Which equation correctly represents the relationship between pH and hydrogen ion concentration $$[H^+]$$?

Accepted Answer

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

Question 6

A buffer is added to a solution to maintain its pH. What is the primary function of a buffer in biological systems?

Accepted Answer

To minimize changes in $$[H^+]$$ and $$[OH^-]$$ concentrations when acids or bases are added

Question 7

Which of the following substances is most likely to dissolve in water, and why?

Accepted Answer

A polar molecule, because it can interact with water's partial charges

Question 8

Which property of water is most important for the transport of water against gravity in plants?

Accepted Answer

Cohesion and adhesion

Question 9

If the pH of a solution changes from 7 to 5, by what factor does the hydrogen ion concentration $$[H^+]$$ increase?

Accepted Answer

100 times

Question 10

Which of the following best describes the type of bond within a water molecule and the type of bond between water molecules?

Accepted Answer

Polar covalent bond within; hydrogen bond between

Question 11

A scientist adds a strong acid to a biological fluid. What role does a buffer play in this scenario?

Accepted Answer

It minimizes the change in pH by absorbing excess $$H^+$$ ions

Question 12

Which of the following is a direct consequence of water's ability to moderate temperature in living organisms?

Accepted Answer

Organisms maintain stable internal temperatures despite external changes

Question 13

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

Accepted Answer

Water's partial charges attract and surround ions, separating them

Question 14

Which of the following statements about hydrophilic and hydrophobic substances is correct?

Accepted Answer

Hydrophilic substances are polar or charged and can form hydrogen bonds with water

Question 15

Which of the following is true about the density of water in its solid and liquid states?

Accepted Answer

Liquid water is more dense than solid water (ice)

Question 16

Which of the following best describes the role of hydrogen bonds in the properties of water?

Accepted Answer

Hydrogen bonds are responsible for water's cohesion, adhesion, high specific heat, and expansion upon freezing

Question 17

A plant is able to transport water from its roots to its leaves. Which two properties of water are most directly responsible for this process?

Accepted Answer

Cohesion and adhesion

Question 18

Which of the following best describes the relationship between pH and $$[H^+]$$ concentration in biological fluids?

Accepted Answer

As pH decreases, $$[H^+]$$ increases

Question 19

Which of the following is a real-world consequence of water's expansion upon freezing?

Accepted Answer

Ice floats, insulating the water below and allowing aquatic life to survive in winter

Properties of Water: Structure, Bonding, and Biological Importance

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