Chemical Bonding, Solid Structures, and Thermochemistry Principles
Classification of Solids and Interparticle Forces
Sulfur Dioxide, SO₂ (Molecular Solid)
- Type of Solid: Simple molecular (molecular solid)
- Type of Particle: Discrete SO₂ molecules
- Attractive Forces: Weak intermolecular forces (van der Waals and dipole–dipole)
Sodium Sulfide, Na₂S(s) (Ionic Solid)
- Type of Solid: Ionic solid (crystalline ionic lattice)
- Type of Particle: Ions (Na⁺ and S²⁻)
- Attractive Forces: Strong electrostatic (ionic) attraction between Na⁺ and S²⁻
Sodium, Na(s) (Metallic
Read MoreKey Concepts in Stellar Physics and Atomic Structure
Fundamental Concepts in Astrophysics and Physics
Atomic Structure and Matter
- Atom
- The smallest unit of a chemical element, consisting of a nucleus containing protons and neutrons plus a surrounding cloud of electrons.
- Nucleus
- The central core of an atom, composed of protons and neutrons, carrying a net positive charge.
- Proton
- A positive atomic particle located in the nucleus of an atom.
- Neutron
- An atomic particle with no charge and approximately the same mass as a proton.
- Electron
- A low-mass atomic particle
Fundamentals of Chemical Elements and Bonding
The Periodic Table of Chemical Elements
All chemical elements are arranged in order of increasing atomic number (Z) in a table called the Periodic Table, in a way that reflects their atomic structure.
The elements are arranged in:
- Seven horizontal rows called periods.
- Eighteen vertical columns called groups.
The periods are classified by length:
- Short periods: The first period (containing two elements: hydrogen and helium) and the two following periods (each with eight elements).
- Long periods: The remaining
Fundamental Concepts in Organic Chemistry: Reactions and Stereoisomerism
Key Organic Reactions and Reductions
The Wolff-Kishner reduction and the Dakin reaction are two important organic reactions, often used alongside Metal Hydride Reductions.
Wolff-Kishner Reduction
- Reaction Type: Reduction reaction
- Purpose: Converts carbonyl groups (aldehydes or ketones) to methylene groups (-CH2-)
- Reagents: Hydrazine (N2H4) and a strong base (usually KOH or NaOH)
- Conditions: High temperature and pressure
Dakin Reaction
- Reaction Type: Oxidation reaction
- Purpose: Converts benzaldehydes to phenols
- Reagents:
Essential Chemistry Concepts and Atomic Theory Timeline
Fundamental Chemistry Concepts and Definitions
Physical and Chemical Properties
- Physical Property: A description that helps identify a substance.
- Quantitative Characteristics: Characteristics that are measured. They always include a number and a unit.
- Qualitative Characteristics: Characteristics observed with the senses that are described but not measured.
- Characteristic Physical Property: A unique physical property used specifically to identify a substance (e.g., density, melting point).
- Chemical Properties:
Acid-Base Equilibrium and pH Calculations
Identifying Acid-Base Problem Types
| Question Type | Problem Category |
|---|---|
| Asks if a salt solution (e.g., NaClO) is acidic, basic, or neutral | Conjugate acid-base salt classification |
| Involves a weak acid concentration and asks for the pH | Weak acid equilibrium problem (requires an ICE table and Kₐ) |
| Involves a salt of a weak acid (e.g., NaC₆H₅CO₂) and asks for the pH | Basic salt hydrolysis problem (involves a conjugate base and Kₑ) |
Core Acid-Base Concepts
Acid-Base Properties of Salts
- Strong acid + Strong base