Aqueous Solutions and Concentrations Module Exam Practice Quiz

Which of the following substances forms an electrolyte solution when dissolved in water?

• Sugar (C₁₂H₂₂O₁₁)

• Ethanol (C₂H₆O)

• Sodium chloride (NaCl)

• Oxygen (O₂)

If a sugar cube is added to the glass of water, which of the following statements best explains what part of the solution the sugar is?

• Sugar is the solute in the solution because it is what the solvent is dissolving.

• Sugar is the solvent in the solution because it is what the solute is dissolving.

• Sugar is the solvent in the solution because it is in solid form.

• Sugar is the solvent in the solution because it is what the solution is dissolving.

Tags

NGSS.MS-PS1-2

Which of the following factors most directly affects the rate at which a solute dissolves in a solvent?

• The color of the solute

• The surface area of the solute

• The shape of the container

• The solvent’s density

Which type of solution can continue to dissolve more solute under the same conditions?

• Supersaturated solution

• Saturated solution

• Unsaturated solution

• Concentrated solution

What is the molarity of a solution if 5.00 g of sodium hydroxide (NaOH) is dissolved in 500 mL of solution? The molar mass of NaOH is 40.00 g/mol.

• 0.01 M

• 10.00 M

• 0.00025 M

• 0.250 M

What is the molality of a solution if 2.50 g of potassium chloride (KCl) is dissolved in 100 g of water? The molar mass of KCl is 74.55 g/mol.

• 0.250 m

• 0.335 m

• 0.500 m

• 0.670 m

Use the solubility rules to answer the question that follows. Which of the given compounds is most likely to be insoluble in water?

• Na₂SO₄ (Sodium sulfate)

• KNO₃ (Potassium nitrate)

• BaSO₄ (Barium sulfate)

• NaCl (Sodium chloride)

Tags

NGSS.HS-ESS2-5

Use the solubility rules to answer the question that follows. What are the spectator ions in the following reaction?

Na₂CO₃ (aq) + CaCl₂ (aq) → CaCO₃ + 2 NaCl

• Na⁺ and Cl⁻

• Na⁺ and Ca²⁺

• Ca²⁺ and CO₃²⁻

• Na⁺ and CO₃²⁻

Answer explanation

Na₂CO₃ (Sodium carbonate) is soluble, so it dissociates into 2 Na⁺ and CO₃²⁻.

CaCl₂ (Calcium chloride) is soluble, so it dissociates into Ca²⁺ and 2 Cl⁻.

CaCO₃ (Calcium carbonate) is insoluble and forms a solid precipitate.

NaCl (Sodium chloride) is soluble, so it dissociates into Na⁺ and Cl⁻.

In the net ionic equation, we only include the species that participate in the reaction, which are Ca²⁺ and CO₃²⁻. These ions combine to form the solid CaCO₃.

The spectator ions are those that do not change during the reaction. These are the ions that remain in solution and do not participate in the formation of the precipitate. In this case, Na⁺ and Cl⁻ are spectator ions because they are present on both sides of the equation without undergoing any change.

As the concentration of solute increases, what happens to the freezing point of a solution?

• It increases

• It decreases

• It remains the same

• It fluctuates depending on the solute

Answer explanation

When a solute is added to a solvent, it disrupts the formation of the solvent’s solid structure, causing the freezing point to drop. The more solute that is added, the lower the freezing point becomes.

For example, adding salt (NaCl) to water lowers the freezing point of the water, preventing it from freezing at 0°C.

What pH values represent bases?

• 1 to 6

• 1 to 4

• 7 to 14

• 8 to 14