Question 1

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

Accepted Answer

Ice is less dense than liquid water due to the stable hydrogen bonds forming a lattice structure.

Question 2

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

Accepted Answer

Surface tension resulting from hydrogen bonding between water molecules.

Question 3

A solution in which water is the solvent is called a(n) ______ solution.

Accepted Answer

Aqueous

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 has a high specific heat?

Accepted Answer

A large amount of energy is required to break hydrogen bonds between water molecules.

Question 6

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

Accepted Answer

Water's ability to moderate temperature due to its high specific heat.

Question 7

Which of the following best explains why salt (NaCl) dissolves in water?

Accepted Answer

The polar water molecules surround and separate the Na$$ ^+ $$ and Cl$$ ^- $$ ions.

Question 8

Which of the following reactions is most consistent with that of a base?

Accepted Answer

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

Question 9

Which of the following best describes the effect of adding an acid such as HCl to pure water?

Accepted Answer

It increases the concentration of $$ \mathrm{H}^+ $$ ions and decreases the pH.

Question 10

Which of the following statements about buffers is true?

Accepted Answer

Buffers minimize changes in pH when acids or bases are added to a solution.

Question 11

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

Accepted Answer

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

Question 12

Which of the following best describes a hydrophobic molecule?

Accepted Answer

A molecule that does not easily dissolve in water.

Question 13

In a neutral solution at 25$$ ^\circ C$$, the concentration of hydrogen ions is:

Accepted Answer

Equal to the concentration of hydroxide ions.

Question 14

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

Accepted Answer

Evaporation of sweat cools the body efficiently.

Question 15

Which of the following best describes the role of buffers in blood?

Accepted Answer

Buffers help maintain a relatively constant pH despite the addition of acids or bases.

Question 16

Which of the following is true about the pH scale?

Accepted Answer

A solution with a pH of 3 has a higher concentration of $$ \mathrm{H}^+ $$ ions than a solution with a pH of 7.

Question 17

Which of the following best explains why lakes and oceans resist rapid temperature changes?

Accepted Answer

Water's high specific heat allows it to absorb or release large amounts of heat with only slight temperature changes.

Question 18

Which of the following is a property of a homogeneous solution?

Accepted Answer

The components are uniformly distributed throughout the solution.

Question 19

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 20

Which of the following is a direct effect of adding a base to an aqueous solution?

Accepted Answer

The concentration of $$ \mathrm{OH}^- $$ ions increases and the pH increases.

Properties of Water: Structure, Behavior, and Chemical Significance

Guida di studio - Domande di pratica