Q: A student prepares a solution by dissolving 25.0 g of KOH (molar mass = 56.11 g/mol) in enough water to make 575 mL of solution. What is the molarity of the solution?

$$M = \frac{25.0\ \text{g}}{56.11\ \text{g/mol}} \div 0.575\ \text{L} = 0.776\ M$$

Question 1

Which of the following best explains why NaCl dissolves in water, as depicted in the images above?

Accepted Answer

The attraction between Na+ and Cl− ions and water molecules (solvent–solute interactions) is strong enough to overcome the solute–solute and solvent–solvent interactions.

Question 2

The partial charges on a water molecule, as shown in the second image, are a result of:

Accepted Answer

The uneven distribution of electrons, with oxygen being more electronegative and pulling electron density toward itself.

Question 3

Which of the following statements about electrolytes is supported by the images showing conductivity tests?

Accepted Answer

A salt solution conducts electricity because it contains free-moving ions.

Question 4

Which of the following best describes the process shown in the image where water molecules surround ions from a salt crystal?

Accepted Answer

Solvation (hydration)

Question 5

A solution of HC2H3O2 (acetic acid) in water is shown in one of the images. Which statement is correct about this solution?

Accepted Answer

It is a weak acid and only partially ionizes in water.

Question 6

Which of the following best explains why AgCl is insoluble in water, as shown in the images?

Accepted Answer

The solute–solute interactions in AgCl are much stronger than the solvent–solute interactions with water.

Question 7

Which of the following solutions would you expect to be a strong electrolyte based on the images and your knowledge of solubility?

Accepted Answer

A solution of NaCl in water

Question 8

Which of the following best describes the interaction between sucrose (sugar) and water molecules as shown in the images?

Accepted Answer

Hydrogen bonds and dipole-dipole interactions occur between sucrose and water.

Question 9

Which of the following statements is supported by the solubility curves shown in the images?

Accepted Answer

The solubility of most solids in water increases as temperature increases, while the solubility of gases decreases.

Question 10

Based on the solubility rules provided, which compound would be expected to be insoluble in water?

Accepted Answer

AgCl

Question 11

A student prepares a solution by dissolving 25.0 g of KOH (molar mass = 56.11 g/mol) in enough water to make 575 mL of solution. What is the molarity of the solution?

Accepted Answer

$$M = \frac{25.0\ 	ext{g}}{56.11\ 	ext{g/mol}} \div 0.575\ 	ext{L} = 0.776\ M$$

Question 12

Which of the following best describes the difference between a dilute and a concentrated solution, as shown in the images of blue solutions?

Accepted Answer

A concentrated solution contains a larger amount of solute relative to solvent.

Question 13

Which of the following best explains why a precipitation reaction occurs when Pb(NO3)2 and KI are mixed, as shown in the images?

Accepted Answer

PbI2 is insoluble in water and forms a solid precipitate.

Question 14

Which of the following is the correct net ionic equation for the reaction between Pb(NO3)2(aq) and KI(aq)?

Accepted Answer

$$	ext{Pb}^{2+}(aq) + 2	ext{I}^-(aq) ightarrow 	ext{PbI}_2(s)$$

Question 15

Which of the following best describes the role of water as a solvent in the dissolution of ionic compounds?

Accepted Answer

Water molecules surround and insulate ions, preventing them from recombining.

Introduction to Solutions and Aqueous Reactions: Study Notes

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