Homogeneous Aqueous Systems Review

Homogeneous Aqueous Systems Overview

• Objectives:

  • Distinguish between solvent and solute.

  • Describe the solution process.

  • Explain why all ionic compounds are electrolytes.

  • Write formulas for hydrates.

• Key Vocabulary:

  • Aqueous solution

  • Solvent

  • Solute

  • Electrolyte

  • Nonelectrolyte

  • Strong electrolyte

  • Weak electrolyte

  • Hydrate

  • Mass of water

  • Percent H2O = $\frac{\text{mass of water}}{\text{mass of hydrate}} \times 100\%$

Part A Completion

• Water is a polar liquid and an excellent solvent for many substances.

• Aqueous solutions are homogeneous mixtures of ions or molecules in water.

• The solubility of a solute depends on solute-solvent interactions.

• A good rule to remember is "like dissolves like."

• Substances that dissolve as ions are known as electrolytes.

• A solute that is completely ionized in solution is a strong electrolyte.

• A weak electrolyte is only partially ionized.

• A solution of an electrolyte will conduct an electric current, whereas a solution of a nonelectrolyte is nonconducting.

• Many crystals are hydrates; they contain water of hydration.

• The process called efflorescence occurs when the water of hydration is lost from a hydrate that is exposed to air.

Part B True-False

1. Carbon tetrafluoride is a nonelectrolyte. (AT)

2. Hydrates are crystals that contain a fixed quantity of water within their structure. (AT)

3. Covalent solutes are very soluble in water. (SC)

4. Solutions are always homogeneous. (AT)

Part C Matching

• Column A

  1. Aqueous solutions

  2. Solute

  3. Solvation

  4. Electrolyte

  5. Nonelectrolytes

  6. Hydrate

  7. Hygroscopic

  8. Desiccants

• Column B
  a. Dissolved particles in a solution
  b. Compounds that conduct electric currents in aqueous solution
  c. Compounds able to remove moisture from air
  d. Water samples containing dissolved substances
  e. Drying agents
  f. Compounds that do not conduct electric currents in aqueous solution
  g. A compound that contains water of hydration
  h. Process that occurs when a solute dissolves

Part D Questions and Problems

• Calculate the percent by mass of water in Glauber’s salt.

• Which of the following substances dissolves to a significant extent in water?

  1. Na2SO4

  2. NaCl

1. Aqueous solutions

   • d. Water samples containing dissolved substances

2. Solute

   • a. Dissolved particles in a solution

3. Solvation

   • h. Process that occurs when a solute dissolves

4. Electrolyte

   • b. Compounds that conduct electric currents in aqueous solution

5. Nonelectrolytes

   • f. Compounds that do not conduct electric currents in aqueous solution

6. Hydrate

   • g. A compound that contains water of hydration

7. Hygroscopic

   • c. Compounds able to remove moisture from air

8. Desiccants

   • e. Drying agents