Theory Worksheet: Chapter 2 - Solutions

 Theory Worksheet: Chapter 2 - Solutions

1. Define the following terms:
   a) Solution
   b) Solute
   c) Solvent
   d) Solubility
   e) Concentration

2. Classify the following solutions as solid, liquid, or gaseous solutions:
   a) Brass
   b) Saltwater
   c) Air
   d) Sugar dissolved in water
   e) Oxygen dissolved in water

3. State the difference between a solute and a solvent in a solution.

4. Explain the term "like dissolves like" with respect to solubility.

5. Discuss the factors that affect the solubility of a solute in a solvent.

6. Differentiate between saturated, unsaturated, and supersaturated solutions.

7. Calculate the mass percentage of solute in a solution if 20 grams of solute is dissolved in 100 grams of the solution.

8. Define the term "molarity" and calculate the molarity of a solution containing 0.5 moles of solute in 250 mL of solution.

9. Explain how temperature affects the solubility of a solid solute in a liquid solvent.

10. State Henry's Law and explain its significance in determining the solubility of gases in liquids.

11. Define the colligative properties of solutions and give examples of each.

12. Explain the concept of osmosis and osmotic pressure.

13. A solution is prepared by dissolving 10 grams of glucose (C6H12O6) in 250 grams of water. Calculate the molality of the solution.

14. How does the addition of a nonvolatile solute affect the boiling point and freezing point of a solvent? Explain with examples.

15. Discuss the importance of solutions in various fields, such as chemistry, biology, medicine, and industry.

Answers:

1. a) Solution: A homogeneous mixture composed of two or more substances.
   b) Solute: The substance present in a smaller amount in a solution.
   c) Solvent: The substance present in a larger amount in a solution.
   d) Solubility: The maximum amount of solute that can be dissolved in a given amount of solvent at a particular temperature.
   e) Concentration: The amount of solute present in a given amount of solvent or solution.

2. a) Solid Solution
   b) Liquid Solution
   c) Gaseous Solution
   d) Liquid Solution
   e) Gaseous Solution

3. Solute is the substance that is present in a smaller amount and gets dissolved in the solvent. Solvent is the substance that is present in a larger amount and dissolves the solute.

4. "Like dissolves like" refers to the principle that polar solutes dissolve in polar solvents, and nonpolar solutes dissolve in nonpolar solvents. This is due to the similar intermolecular forces between the solute and solvent molecules.

5. The factors affecting solubility are:

   • Nature of the solute and solvent
   • Temperature
   • Pressure (for gas solutes)

6. Saturated Solution: A solution that contains the maximum amount of solute that can be dissolved at a given temperature.
   Unsaturated Solution: A solution that can dissolve more solute at a given temperature.
   Supersaturated Solution: A solution that contains more solute than the maximum amount that can normally be dissolved at a given temperature. It is unstable and can be formed under certain conditions.

7. Mass Percentage = (Mass of Solute / Mass of Solution) x 100
   Mass Percentage = (20 g / 100 g) x 100 = 20%

8. Molarity (M) = (Number of Moles of Solute) / (Volume of Solution in Liters)
   Given: Moles of solute = 0.5 moles
   Volume of solution = 250 mL = 0.25 L
   Molarity = 0.5 moles / 0.25 L = 2 M

9. In general, the solubility of a solid solute in a liquid solvent increases with an increase in temperature.

10. Henry's Law states that the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid. It is important in determining the solubility of gases in liquids, especially under different pressures.

11. Colligative properties of solutions depend on the number of solute particles rather than their nature. Examples include:

    • Vapor Pressure Lowering
    • Boiling Point Elevation
    • Freezing Point Depression
    • Osmotic Pressure

12. Osmosis is the movement of solvent molecules from a region of lower solute concentration to a region of higher solute concentration through a semipermeable membrane. Osmotic pressure is the pressure applied to stop the flow of solvent molecules through the membrane.

13. Molality (m) = (Number of Moles of Solute) / (Mass of Solvent in kg)
    Given: Mass of glucose = 10 g
    Mass of water = 250 g = 0.25 kg
    Number of moles of glucose = 10 g / molar mass of glucose
    Molality = (Number of moles of glucose) / (Mass of water in kg)

14. Addition of a nonvolatile solute raises the boiling point and lowers the freezing point of the solvent. The increase in boiling point and decrease in freezing point depend on the molal concentration of the solution. Examples: antifreeze solutions, saltwater.

15. Solutions are of great importance in various fields:

    • In chemistry, solutions are used for chemical reactions, as solvents, and for analytical purposes.
    • In biology, solutions are essential for cellular processes, transportation of substances, and maintaining homeostasis.
    • In medicine, solutions are used for intravenous fluids, drug formulations, and medical treatments.
    • In industry, solutions are used in manufacturing processes, formulation of products, and as solvents in various industries.