Q: If the pH of a solution changes from 6 to 4, what happens to the hydrogen ion concentration $[H^+]$?

$[H^+]$ increases by 100\times$

Question 1

Which property of water is primarily responsible for the upward movement of water in plants against gravity, as seen in the process of transpiration?

Accepted Answer

Cohesion due to hydrogen bonding

Question 2

A scientist is studying a pond during a hot summer day. Despite the high air temperature, the pond's temperature remains relatively stable. Which property of water best explains this phenomenon?

Accepted Answer

Water's high specific heat

Question 3

Why does sweating help cool the human body during exercise?

Accepted Answer

Evaporation of sweat removes heat from the body due to water's high heat of vaporization

Question 4

Which of the following best explains why ice floats on liquid water?

Accepted Answer

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

Question 5

A solution is made by dissolving 10 g of NaCl (molar mass = 58.44 g/mol) in enough water to make 1 L of solution. What is the molarity ($M$) of the solution? Use the formula $M = \frac{	ext{moles of solute}}{	ext{liters of solution}}$.

Accepted Answer

$M = \frac{10}{58.44} = 0.171$ M

Question 6

Which of the following substances would most likely be hydrophobic?

Accepted Answer

Vegetable oil

Question 7

A beaker contains pure water at 25°C. If you add a strong acid to the water, what happens to the concentration of $[H^+]$ and the pH?

Accepted Answer

$[H^+]$ increases and pH decreases

Question 8

Which of the following best describes the function of a buffer in a biological system?

Accepted Answer

A buffer maintains a constant pH by accepting or donating $H^+$ ions

Question 9

If the pH of a solution changes from 6 to 4, what happens to the hydrogen ion concentration $[H^+]$?

Accepted Answer

$[H^+]$ increases by 100	imes$

Question 10

Which property of water allows insects such as water striders to walk on the surface of a pond?

Accepted Answer

High surface tension due to hydrogen bonding

Question 11

A marine biologist observes that coral reefs are being damaged due to ocean acidification. Which chemical process is most directly responsible for this phenomenon?

Accepted Answer

Increased atmospheric $CO_2$ dissolving in seawater, forming carbonic acid

Question 12

Which of the following statements about water's heat of vaporization is correct?

Accepted Answer

It is the amount of heat required to convert 1 g of water from liquid to gas

Question 13

A student adds sugar to water and observes that it dissolves completely. Which term best describes the sugar in this scenario?

Accepted Answer

Solute

Question 14

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

Accepted Answer

Water has a high specific heat, so it absorbs and releases heat slowly

Question 15

A solution has a pH of 3. What is the $[H^+]$ concentration in moles per liter? Use the formula $[H^+] = 10^{-pH}$.

Accepted Answer

$[H^+] = 10^{-3} = 0.001$ M

Question 16

Which of the following is a consequence of water's high heat of vaporization for living organisms?

Accepted Answer

Evaporation of water from surfaces cools organisms efficiently

Question 17

Which of the following best describes why water is called the 'universal solvent'?

Accepted Answer

Water can dissolve a wide variety of substances due to its polarity

Question 18

A solution contains 0.01 moles of $H^+$ per liter. What is the pH of the solution? Use the formula $pH = -\log_{10}[H^+]$.

Accepted Answer

pH = 4

Question 19

Which of the following scenarios best illustrates the concept of evaporative cooling?

Accepted Answer

A dog pants to cool itself on a hot day

Question 20

Which of the following is NOT a direct result of hydrogen bonding between water molecules?

Accepted Answer

Water's ability to dissolve nonpolar substances

Hydrogen Bonding and the Unique Properties of Water

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