Overview
This lecture covers the fundamental concepts of solutions and gas laws, including types, properties, and calculations related to concentration and gas behavior.
Components and Classification of Solutions
- A solute is the substance dissolved; a solvent is the dissolving medium.
- Solutions can be gas, liquid, or solid types based on solute and solvent states.
- Degree of saturation: saturated (maximum solute), unsaturated (less solute), and supersaturated (more than maximum solute).
- Miscible liquids dissolve in all proportions; immiscible liquids do not dissolve in each other.
- Isotonic solutions have equal solute concentrations; hypotonic have lower, hypertonic have higher concentrations.
Properties and Solubility of Solutions
- Solutions are homogeneous, clear, do not settle, and can be separated physically.
- Solubility measures how much solute dissolves at a given temperature.
- Factors affecting solubility: temperature, pressure, surface area, nature of solvent, stirring.
Concentration of Solutions
- Concentration refers to the amount of solute in a given amount of solution.
- Concentrated solutions have more solute; dilute solutions have less.
- Weight/volume percent: % W/V = (grams solute / milliliters solution) × 100.
- Weight/weight percent: % W/W = (grams solute / grams solvent) × 100.
- Molarity (M) = moles of solute / liter of solution.
- Molality (m) = moles of solute / kilogram of solvent.
- Normality (N) = gram-equivalent weight of solute / liter of solution.
Oxidation and Reduction
- Oxidation: gain of oxygen or loss of electrons (increase in oxidation number).
- Reduction: gain of hydrogen or electrons (decrease in oxidation number).
Properties and Laws of Gases
- Gases have wide particle spacing, expand to fill containers, no definite volume, are compressible, and have low density.
- Gas quantities: pressure (P), temperature (T), volume (V), number of particles (n), molecular mass (m).
- Boyle’s Law: P₁V₁ = P₂V₂ (at constant T and n).
- Charles’ Law: V₁/T₁ = V₂/T₂ (at constant P and n).
- Gay-Lussac’s Law: P₁/T₁ = P₂/T₂ (at constant V and n).
- Combined Gas Law deals with changes in P, V, and T.
- Avogadro’s Law: V₁/n₁ = V₂/n₂ (at constant T and P).
- Ideal Gas Law: PV = nRT.
Key Terms & Definitions
- Solute — the dissolved substance in a solution.
- Solvent — the medium that dissolves the solute.
- Saturated Solution — contains the maximum amount of dissolved solute.
- Molarity (M) — moles of solute per liter of solution.
- Molality (m) — moles of solute per kilogram of solvent.
- Normality (N) — gram-equivalent weight of solute per liter of solution.
- Boyle’s Law — pressure and volume are inversely related at constant temperature and moles.
- Charles’ Law — volume and temperature are directly related at constant pressure and moles.
- Gay-Lussac’s Law — pressure and temperature are directly related at constant volume and moles.
- Avogadro’s Law — volume is directly proportional to moles at constant temperature and pressure.
- Ideal Gas Law — relates P, V, n, T using PV = nRT.
Action Items / Next Steps
- Practice solving concentration and gas law problems as presented in the examples.
- Review key formula derivations and applications for each law.
- Prepare for potential quizzes on definitions, laws, and calculation methods.