General Chemistry - Part 2: Key Concepts and Problem Solving Techniques

Chemical Kinetics

• Rate Law Expression

  • How to write the rate law expression.
  • Find the rate constant (k).
  • Understand the reaction mechanism.

• Order of Reactions

  • Zero-order, first-order, and second-order reactions.
  • Calculation and understanding changes in concentration over time.
  • Graphical analysis for each reaction order.

Nuclear Chemistry

• Identifying Missing Elements

  • Understand nuclear reactions and balance them.

• Nuclear Binding Energy

  • Calculation methods.

• Half-life Problems

  • Using the half-life concept to solve various decay problems.

Chemical Equilibrium

• Le Chatelier's Principle

  • Predict shifts in equilibrium with changes in concentration, pressure, volume, or temperature.

• Equilibrium Constant (K)

  • Calculations under different conditions.

• ICE Tables

  • Using ICE tables to solve equilibrium problems involving quadratic formulas.

Acids and Bases

• Calculating pH

  • Strong acids and bases.
  • Weak acids and bases.
  • Buffer solutions.

• Titration Calculations

  • pH before, after, and during titration.

Solubility Product (Ksp)

• Calculation of Ksp

  • Calculate Ksp values from given concentrations.
  • Find molar solubility in moles per liter and grams per liter.

• Le Chatelier's Principle and Ksp

  • How concentration changes affect solubility and pH of solutions.

Thermodynamics

• Gibbs Free Energy (ΔG)
  • Calculation and interpretation under standard and non-standard conditions.
  • Relationship between ΔG, ΔH (enthalpy), and ΔS (entropy).

Electrochemistry

• Cell Potential (E°)

  • Calculation under standard and non-standard conditions.
  • Identifying oxidizing and reducing agents.

• Balancing Redox Reactions

  • For acidic and basic conditions.

• Electrolysis Problems

  • Calculate mass deposited on a cathode given electric current and time.
  • Calculate electric current from mass plated and time.

Problem Solving Example Breakdown

1. Average Rate of Appearance/Disappearance

   • Use molarity and mole ratios to find rates.
   • Understand positive (appearance) vs. negative (disappearance) rates.

2. Rate Law Problem

   • Analyze experimental data to determine rate law and rate constant.
   • Understand concentration effects on reaction rates.

3. Graphical Plots for Reactions

   • Identify reaction order through graphical analysis (ln[A] vs. time).

4. Units of Rate Constants

   • Determine units based on reaction order.
   • Use formula: M^(1-n)S^(-1).

5. Zero-order, First-order, and Second-order Calculations

   • Use appropriate formulas and graphical methods to solve for concentration, time, and rate constants.

6. Activation Energy Calculation

   • Use Arrhenius equation and given data to determine activation energy (Ea).

7. Equilibrium Constant Problems

   • Write correct expressions, calculate Kc, and interpret equilibrium constants.

8. pH and pOH Calculations

   • Use given concentrations and, if necessary, equilibrium constants (Ka, Kb) to find pH or pOH.

9. Buffer Solution Calculations

   • Use Henderson-Hasselbalch equation to determine pH of buffers.

10. Solubility and Ksp Problems

    • Calculate molar solubility from Ksp values and vice versa.
    • Understand the effect of common ions on solubility.

11. Thermodynamic Relationships

    • Apply ΔG = ΔH - TΔS to determine spontaneity of reactions under given conditions.
    • Use K and ΔG relationships to validate reaction spontaneity.

12. Electrochemical Cell Calculations

    • Calculate cell potentials using standard and Nernst equation for non-standard conditions.
    • Balance redox reactions correctly.