Untitled Flashcards Set

Key Vocabulary & Definitions:

  1. Boiling Point Elevation – The increase in the boiling point of a solvent when a solute is added due to decreased vapor pressure.

  2. Brownian Motion – The random movement of particles in a colloid due to collisions with solvent molecules.

  3. Colloids – A mixture with intermediate-sized particles that remain suspended indefinitely and exhibit the Tyndall effect.

  4. Freezing Point Depression – The decrease in the freezing point of a solvent when a solute is added, preventing the solvent from forming a solid at its normal freezing temperature.

  5. Immiscible – Two liquids that do not mix to form a homogeneous solution (e.g., oil and water).

  6. Insoluble – A substance that does not dissolve in a solvent.

  7. Miscible – Two liquids that dissolve in each other in any proportion (e.g., alcohol and water).

  8. Molarity (M) – The concentration of a solution, measured in moles of solute per liter of solution. Formula: M=moles of soluteliters of solutionM = \frac{\text{moles of solute}}{\text{liters of solution}}M=liters of solutionmoles of solute​

  9. Molality (m) – The concentration of a solution, measured in moles of solute per kilogram of solvent. Formula: m=moles of solutekg of solventm = \frac{\text{moles of solute}}{\text{kg of solvent}}m=kg of solventmoles of solute​

  10. Solubility – The ability of a solute to dissolve in a solvent at a given temperature and pressure.

  11. Solvation – The process of dissolving, where solvent molecules surround and interact with solute particles.

  12. Tyndall Effect – The scattering of light by particles in a colloid, making the light beam visible (e.g., fog and headlights).

Types of Colloids & Examples:

  1. Sol – A solid dispersed in a liquid (e.g., paint, blood).

  2. Gel – A liquid dispersed in a solid (e.g., gelatin, butter).

  3. Aerosol – A liquid or solid dispersed in a gas (e.g., fog, smoke).

  4. Foam – A gas dispersed in a liquid or solid (e.g., whipped cream, styrofoam).

  5. Emulsion – A liquid dispersed in another liquid (e.g., milk, mayonnaise).

Mixtures:

  • Homogeneous Mixtures (Solutions): Uniform throughout (e.g., saltwater, air).

  • Heterogeneous Mixtures: Not uniform throughout (e.g., sand and water, salad dressing).

Concentration Ratios to Know:

  1. Molarity (M): M=moles of soluteliters of solutionM = \frac{\text{moles of solute}}{\text{liters of solution}}M=liters of solutionmoles of solute​

  2. Molality (m): m=moles of solutekg of solventm = \frac{\text{moles of solute}}{\text{kg of solvent}}m=kg of solventmoles of solute​

  3. Percent by Mass: %Mass=mass of solutetotal mass of solution×100\% \text{Mass} = \frac{\text{mass of solute}}{\text{total mass of solution}} \times 100%Mass=total mass of solutionmass of solute​×100

  4. Percent by Volume: %Volume=volume of solutetotal volume of solution×100\% \text{Volume} = \frac{\text{volume of solute}}{\text{total volume of solution}} \times 100%Volume=total volume of solutionvolume of solute​×100

  5. Mole Ratio: The ratio of moles of one substance to another in a balanced equation.

Electrolytes & Non-Electrolytes:

  • Electrolytes: Conduct electricity when dissolved in water (e.g., salt, acids, bases).

  • Non-Electrolytes: Do not conduct electricity in solution (e.g., sugar, alcohol).

Solubility Principles:

  1. Factors Affecting Solubility:

    • Temperature: Higher temperature increases solubility for solids but decreases it for gases.

    • Pressure: Higher pressure increases gas solubility in liquids (Henry’s Law).

    • Polarity: "Like dissolves like" (polar solvents dissolve polar solutes, nonpolar solvents dissolve nonpolar solutes).

  2. Saturated Solution: Contains the maximum amount of dissolved solute at a given temperature.

  3. Supersaturated Solution: Contains more dissolved solute than a saturated solution at the same temperature and is unstable.

Colligative Properties:

  1. Boiling Point Elevation:

    • Adding a solute increases the boiling point of the solvent.

  2. Freezing Point Depression:

    • Adding a solute lowers the freezing point (e.g., salt on icy roads).

Example:
The ocean doesn’t freeze at 0°C because it is a solution that undergoes freezing point depression.

How to Separate Mixtures:

  • Best & fastest way to separate sand and water: Filtration.

  • Other methods: Evaporation, distillation, chromatography, and centrifugation.

Extra Key Concepts to Know:

  • Water is the most abundant solvent on Earth.

  • Hydrogen bonding in water causes its high boiling point.

  • To add more solute to an already saturated solution, increase temperature or pressure (if dealing with gases).

Practice Problems:

  1. Molarity Calculation:

    • Given: 10.0 g of NaCl (molar mass = 58.44 g/mol) dissolved in 2.0 L of water.

    • Solution: Moles of NaCl=10.0 g58.44 g/mol=0.171 moles\text{Moles of NaCl} = \frac{10.0 \text{ g}}{58.44 \text{ g/mol}} = 0.171 \text{ moles}Moles of NaCl=58.44 g/mol10.0 g​=0.171 moles M=0.171 moles2.0 L=0.0855 MM = \frac{0.171 \text{ moles}}{2.0 \text{ L}} = 0.0855 \text{ M}M=2.0 L0.171 moles​=0.0855 M

  2. Molality Calculation:

    • Given: 20.0 g of glucose (molar mass = 180 g/mol) dissolved in 200 g of water.

    • Solution: Moles of glucose=20.0180=0.111 moles\text{Moles of glucose} = \frac{20.0}{180} = 0.111 \text{ moles}Moles of glucose=18020.0​=0.111 moles Mass of solvent=2001000=0.200 kg\text{Mass of solvent} = \frac{200}{1000} = 0.200 \text{ kg}Mass of solvent=1000200​=0.200 kg m=0.1110.200=0.555 mm = \frac{0.111}{0.200} = 0.555 \text{ m}m=0.2000.111​=0.555 m

Final Study Tips:

  • Memorize key vocabulary & definitions.

  • Practice molarity & molality calculations.

  • Understand colligative properties (boiling point elevation & freezing point depression).

  • Know how to classify mixtures (homogeneous vs. heterogeneous, colloids, suspensions, solutions).

  • Understand solubility and factors that affect it.

  • Be