Question 1

Which property of water is primarily responsible for the ability of trees to transport water from their roots to their leaves against gravity?

Accepted Answer

Cohesion due to hydrogen bonding

Question 2

Why does ice float on liquid water, and what is the biological significance of this property?

Accepted Answer

Hydrogen bonds in ice are more ordered and stable, making ice less dense than liquid water, which insulates aquatic environments.

Question 3

A solution has a hydrogen ion concentration of $$1 	imes 10$$^{-7}$$ M. What is the pH of this solution?

Accepted Answer

$$pH = 7$$

Question 4

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

Accepted Answer

Water molecules are polar and form hydration shells around ions.

Question 5

If 10 grams of water absorbs 418.4 J of heat, by how many degrees Celsius will its temperature increase? (Specific heat of water = $$4.184 \ \mathrm{J/g}^\circ\mathrm{C})$$

Accepted Answer

$$1^\circ\mathrm{C}$$

Question 6

Which of the following scenarios best illustrates the concept of a buffer in biological systems?

Accepted Answer

A solution that resists changes in pH when small amounts of acid or base are added.

Question 7

Which of the following is a direct consequence of water’s high specific heat for life on Earth?

Accepted Answer

Stable ocean temperatures that support marine life.

Question 8

A patient’s blood pH drops to 7.1. What is the most immediate risk to their health, and why?

Accepted Answer

Severe illness or death, because blood pH below 7.35 disrupts cellular processes.

Question 9

Which of the following best describes the difference between cohesion and adhesion in water?

Accepted Answer

Cohesion is the attraction between water molecules; adhesion is the attraction between water and other substances.

Question 10

Which of the following statements about acids and bases is correct?

Accepted Answer

A strong acid dissociates completely in water, increasing $$\mathrm{H}^+$$ concentration.

Question 11

Which property of water allows a water strider to walk on the surface of a pond?

Accepted Answer

Surface tension due to hydrogen bonding

Question 12

What happens to the temperature of water when hydrogen bonds form?

Accepted Answer

The temperature decreases because heat is released.

Question 13

Which of the following best explains why water can dissolve large polar molecules such as proteins?

Accepted Answer

Water’s polarity allows it to interact with ionic and polar regions of proteins.

Question 14

If a solution has a pH of 3, what is the concentration of hydrogen ions ($$[\mathrm{H}^+]) in $$the solution?

Accepted Answer

$$[\mathrm{H}^+] = 1 	imes 10$$^{-3}$$ \ \mathrm{M}$$

Question 15

Which of the following is a real-life example of water’s ability to moderate temperature?

Accepted Answer

Coastal cities experience milder climates compared to inland cities.

Question 16

A buffer solution contains a weak acid and its conjugate base. What happens when a small amount of strong acid is added to this buffer?

Accepted Answer

The weak base in the buffer neutralizes the added acid, minimizing pH change.

Question 17

Which of the following best describes the relationship between $$[\mathrm{H}^+]$$ and $$[\mathrm{OH}^-] in $$pure water at 25°C?

Accepted Answer

$$[\mathrm{H}^+] = [\mathrm{OH}^-]$$

Question 18

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

Accepted Answer

High density of ice compared to liquid water

Question 19

Which of the following best explains why strong acids and bases can be dangerous to living organisms?

Accepted Answer

They completely dissociate in water, drastically altering $$[\mathrm{H}^+] or$$ $$[\mathrm{OH}^-]$$ and disrupting cellular processes.

Chapter 3: Water and Life – Properties, Functions, and Biological Importance

Study Guide - Practice Questions

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