Question 1

Which property of water allows a water strider to walk on the surface of a pond without sinking?

Accepted Answer

Cohesion due to hydrogen bonding

Question 2

Why is the water molecule (H$$_2O) $$considered polar?

Accepted Answer

Because it has polar covalent bonds and an asymmetrical (bent) shape

Question 3

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

Accepted Answer

Hydrogen bonds in ice are more stable and hold molecules further apart, making ice less dense

Question 4

A solution has a hydrogen ion concentration of $$[H^+] = 1 	imes 10$$^{-4}$$ M. What is its pH?

Accepted Answer

$$4$$

Question 5

Which of the following bonds is the strongest under physiological conditions?

Accepted Answer

Covalent bond

Question 6

Why does table salt (NaCl) dissolve easily in water?

Accepted Answer

Because water molecules surround and separate the Na$$^+$$ and Cl$$^-$$ ions due to their polarity

Question 7

Which of the following statements about hydrogen bonds is TRUE?

Accepted Answer

Hydrogen bonds form between a partially positive hydrogen and a highly electronegative atom like O or N

Question 8

A solution with a pH of 5 has how many times more hydrogen ions than a solution with a pH of 7?

Accepted Answer

100 times more

Question 9

Which of the following best describes why water is an excellent solvent for polar substances?

Accepted Answer

Water molecules form hydrogen bonds with polar solutes, allowing them to dissolve

Question 10

Which of the following is NOT an emergent property of water due to hydrogen bonding?

Accepted Answer

Ice sinking in water

Question 11

Which of the following molecules is most likely to be hydrophobic?

Accepted Answer

A molecule with many C-H bonds and a symmetrical shape

Question 12

Which of the following best explains why coastal regions have milder climates than inland regions?

Accepted Answer

Water can absorb and release large amounts of heat with only slight temperature changes

Question 13

Which of the following is true about the bond between the oxygen and hydrogen within a water molecule?

Accepted Answer

It is a polar covalent bond

Question 14

If the pH of a solution changes from 8 to 6, what happens to the hydrogen ion concentration?

Accepted Answer

It increases by 100 times

Question 15

Which of the following best describes the role of buffers in biological systems?

Accepted Answer

Buffers resist changes in pH by accepting or donating H$$^+$$ ions

Question 16

Which of the following is a real-life example of adhesion?

Accepted Answer

Water being pulled up through the vessels of a plant

Question 17

Which of the following statements about pH is correct?

Accepted Answer

A solution with pH 7 is neutral because $$[H^+] = [OH^-]$$

Question 18

Which of the following best explains why nonpolar molecules do not dissolve in water?

Accepted Answer

Nonpolar molecules are repelled by water due to lack of charge separation

Question 19

Which of the following is an example of a polar covalent bond?

Accepted Answer

O-H bond in water

Question 20

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

Accepted Answer

pH decreases as [H$$^+$$] increases

Water: Structure, Properties, and Biological Importance

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