Question 1

Which property of water is primarily responsible for the ability of ice to float on liquid water?

Accepted Answer

Water's expansion upon freezing due to hydrogen bonding

Question 2

A scientist is studying a plant's ability to transport water from its roots to its leaves. Which two properties of water are most directly involved in this process?

Accepted Answer

Cohesion and adhesion

Question 3

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

Accepted Answer

Because hydrogen bonds absorb and release heat when they break and form

Question 4

Which equation correctly represents the dissociation of water into hydrogen and hydroxide ions?

Accepted Answer

$$H_2O \rightarrow H^+ + OH^-$$

Question 5

A solution has a pH of 4. Which of the following statements is true about this solution?

Accepted Answer

It is acidic and has a high concentration of $$H^+$$ ions.

Question 6

Which of the following best explains why coastal areas tend to have milder climates than inland areas?

Accepted Answer

Water's high specific heat allows it to absorb and release large amounts of heat with little temperature change.

Question 7

Which of the following is a consequence of ocean acidification caused by increased $$CO_2$$ absorption?

Accepted Answer

Decreased availability of carbonate ions for calcification

Question 8

A buffer solution contains a weak acid and its corresponding base. What is the main function of this buffer in biological systems?

Accepted Answer

To minimize changes in $$[H^+]$$ and $$[OH^-]$$ concentrations

Question 9

Which of the following substances would be considered hydrophobic?

Accepted Answer

Vegetable oil

Question 10

If the concentration of $$H^+ in a $$solution is $$1 	imes 10$$^{-6}$$ M, what is the pH of the solution?

Accepted Answer

$$pH = 6$$

Question 11

Which property of water allows insects to walk on its surface?

Accepted Answer

High surface tension due to cohesion

Question 12

During a hot day, sweating helps cool the human body. Which property of water is responsible for this cooling effect?

Accepted Answer

Evaporative cooling due to water's high heat of vaporization

Question 13

Which of the following best describes the molecular structure of water?

Accepted Answer

Polar molecule with partial negative charge on oxygen and partial positive charges on hydrogens

Question 14

A marine biologist observes that coral reefs are declining in areas with increased $$CO_2$$ emissions. What is the most likely chemical explanation for this phenomenon?

Accepted Answer

Increased $$CO_2$$ forms carbonic acid, reducing carbonate ion availability needed for calcification.

Question 15

Which of the following best explains why water is called the 'solvent of life'?

Accepted Answer

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

Question 16

Which of the following equations represents the formation of carbonic acid in seawater due to $$CO_2$$ absorption?

Accepted Answer

$$CO_2 + H_2O$$ \rightarrow H_2CO_3$$

Question 17

A student adds hydrochloric acid ($$HCl) to $$pure water. What will happen to the $$[H^+]$$ concentration and the pH?

Accepted Answer

$$[H^+]$$ will increase and pH will decrease

Question 18

Which of the following is true about the density of water as it changes from liquid to solid?

Accepted Answer

Water becomes less dense as it freezes because hydrogen bonds keep molecules farther apart.

Question 19

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

Accepted Answer

Hydrogen bonds allow water molecules to stick together, resulting in high cohesion and surface tension.

Question 20

A weak acid is added to a buffer solution. What will happen to the pH of the solution?

Accepted Answer

The pH will remain relatively stable due to the buffer's action.

Water and Life: Properties and Biological Importance

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