Kinetic Molecular Theory and Properties of Matter

Kinetic Molecular Theory (KMT)

  • Gases have no intermolecular forces (IMFs), leading to low density, high compressibility, and diffusion.
  • Liquids have moderate IMFs, higher density than gases, defined volume but no defined shape, and can diffuse.
  • Solids have strong IMFs, high density, and defined volume and shape, with negligible compressibility and no diffusion.

Key Concepts of KMT

  • Average kinetic energy varies among molecules even at the same temperature due to collisions and energy exchange.
  • The average kinetic energy of solids equals that of liquids at the same temperature, but molecular movement differs.

Types of Bonds

Intramolecular Bonds:

  • Ionic Bond: Transfer of electrons between highly and low electronegative (EN) atoms.
  • Covalent Bond: Electrons shared between atoms with similar EN.
  • Metallic Bond: Delocalized electrons moving among metallic nuclei.

Intermolecular Bonds (Listed by increasing strength):

  1. London Dispersion Forces (between nonpolar molecules)
  2. Ion-Induced Dipole/Dipole-Induced Dipole
  3. Dipole-Dipole
  4. Hydrogen Bonding (specific to water, HF, NH3)

Properties of Matter

  • Solids:
    • High solubility, conductivity (due to electron/ion movement), malleability (nondirectional covalent bonds), and brittleness (like charges repel).
  • Liquids: Have defined volume but no shape, and diffuse.
  • Gases: No defined shape or volume, easily compressed, and can diffuse.

Solution Types and Properties

  • Interstitial Alloys: Smaller atoms fit between larger metal atoms.
  • Substitutional Alloys: One metal type replaces another of similar size.

Volatility and Properties Comparison

  • Alcohol is more volatile than water due to weaker bonding (fewer hydrogen bonds).
  • Water has high surface tension due to hydrogen bonding, resulting in low volatility and slow evaporation.