Q: A solution has a pH of 5. What is the concentration of hydrogen ions $$[H^+] in $$this solution?

$$[H^+] = 1 \times 10$$^{-5}$$ M

Question 1

Which property of water is primarily responsible for the phenomenon of surface tension, allowing insects like water striders to walk on water?

Accepted Answer

Cohesion between water molecules due to hydrogen bonding

Question 2

A scientist adds salt to water and observes that the salt dissolves completely. Which property of water allows it to dissolve ionic compounds like salt?

Accepted Answer

Water's polarity and ability to form hydration shells around ions

Question 3

Which equation correctly expresses the relationship between the molarity $$(M)$$, moles of solute $$(n)$$, and volume of solution $$(V) in $$liters?

Accepted Answer

$$M = \frac{n}{V}$$

Question 4

Why does ice float on liquid water?

Accepted Answer

Hydrogen bonds in ice keep water molecules farther apart, making ice less dense

Question 5

Which of the following best explains why coastal areas experience milder climates compared to inland areas?

Accepted Answer

Water's high specific heat moderates temperature fluctuations

Question 6

A solution has a pH of 5. What is the concentration of hydrogen ions $$[H^+] in $$this solution?

Accepted Answer

$$[H^+] = 1 	imes 10$$^{-5}$$ M

Question 7

Which property of water allows it to absorb or release a large amount of heat with only a slight change in its own temperature?

Accepted Answer

High specific heat

Question 8

A plant cell is able to transport water from its roots to its leaves against gravity. Which combination of water properties is most directly responsible for this process?

Accepted Answer

Adhesion and cohesion

Question 9

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

Accepted Answer

An acid is a substance that releases $$H^+$$ ions

Question 10

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

Accepted Answer

To minimize changes in concentrations of $$H^+$$ and $$OH^-$$ ions

Question 11

Which of the following best describes the process of evaporative cooling?

Accepted Answer

As water evaporates, the remaining surface cools due to loss of high-energy molecules

Question 12

A solution is prepared by dissolving 0.5 moles of NaCl in 1 liter of water. What is the molarity $$(M) of $$the solution?

Accepted Answer

$$M = 0.5 M$$

Question 13

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

Accepted Answer

Water has a high specific heat

Question 14

If the concentration of $$[H^+] in a $$solution is $$1 	imes 10$$^{-8}$$ M, what is the pH of the solution?

Accepted Answer

pH = 8

Question 15

Which of the following best explains why oil does not dissolve in water?

Accepted Answer

Oil molecules are hydrophobic and have many nonpolar bonds

Question 16

A patient’s blood pH drops from 7.4 to 7.0. Which buffer system response would help restore normal pH?

Accepted Answer

Bicarbonate accepts $$H^+ to $$make carbonic acid

Question 17

Which of the following is NOT one of the four emergent properties of water that contribute to Earth's suitability for life?

Accepted Answer

High reactivity with nonpolar molecules

Question 18

Which of the following best describes the difference between a strong acid and a weak acid in water?

Accepted Answer

Strong acids dissociate completely, while weak acids dissociate only partially

Question 19

Which of the following equations correctly represents the relationship between pH and hydrogen ion concentration?

Accepted Answer

$$	ext{pH} = -\log [H^+]$$

Question 20

A student mixes a weak acid and its corresponding base in water. What will happen to the pH of the solution if a small amount of strong acid is added?

Accepted Answer

The buffer will minimize the change in pH

Properties of Water and Their Biological Significance

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