Question 1

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

Accepted Answer

Hydrogen bonds in ice form a lattice structure that spaces molecules farther apart, making ice less dense than liquid water.

Question 2

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

Accepted Answer

Surface tension due to hydrogen bonding

Question 3

A solution is made by dissolving table salt (NaCl) in water. In this scenario, which term best describes water?

Accepted Answer

Solvent

Question 4

Which of the following statements about hydrogen bonds in water is correct?

Accepted Answer

Hydrogen bonds form between the hydrogen atom of one water molecule and the oxygen atom of another water molecule.

Question 5

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

Accepted Answer

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

Question 6

Which of the following is an emergent property of water that is essential for life on Earth?

Accepted Answer

Water expands upon freezing, causing ice to float.

Question 7

A scientist adds hydrochloric acid (HCl) to pure water. What is the immediate effect on the solution?

Accepted Answer

The concentration of hydrogen ions increases and the pH decreases.

Question 8

Which of the following best explains why sweating cools the human body?

Accepted Answer

Evaporation of sweat absorbs heat energy from the body due to water's high heat of vaporization.

Question 9

Which of the following best describes a buffer in an aqueous solution?

Accepted Answer

A buffer resists changes in pH by donating or accepting H$$^+$$ ions as needed.

Question 10

Which of the following is true about the pH scale?

Accepted Answer

A solution with pH 7 is neutral, with equal concentrations of H$$^+$$ and OH$$^-$$ ions.

Question 11

Which of the following best describes a hydrophobic molecule?

Accepted Answer

It is nonpolar and does not dissolve easily in water.

Question 12

Which of the following statements about cohesion and adhesion is correct?

Accepted Answer

Cohesion is the ability of water molecules to stick to each other, while adhesion is the ability to stick to other substances.

Question 13

Which of the following best explains why water has a high specific heat?

Accepted Answer

Hydrogen bonding between water molecules requires more energy to change temperature.

Question 14

Which of the following is a correct representation of a base dissociating in water?

Accepted Answer

$$\mathrm{NaOH} \rightarrow \mathrm{Na}^+ + \mathrm{OH}^-$$

Question 15

Which of the following best describes a homogeneous solution?

Accepted Answer

A solution in which the components are uniformly distributed.

Question 16

Which of the following is a direct result of water's high heat of vaporization?

Accepted Answer

Evaporation of water cools surfaces, such as skin, efficiently.

Question 17

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

Accepted Answer

Bases decrease the concentration of H$$^+$$ ions in solution.

Question 18

Which of the following best describes the charge distribution in a water molecule?

Accepted Answer

The oxygen atom is partially negative and the hydrogen atoms are partially positive.

Question 19

Which of the following is a function of buffers in biological systems?

Accepted Answer

Buffers maintain a constant pH by donating or accepting H$$^+$$ ions.

Question 20

Which of the following best explains why lakes and oceans help moderate Earth's climate?

Accepted Answer

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

Properties of Water: Structure, Behavior, and Chemical Reactions

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