W4

• Molecule


  A group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction
• Polar bond


  It is formed when electrons are shared unequally by two atoms in a molecule. The molecule has one positive end and one negative end
• Lone pair


  A pair of valence electrons that are not shared with another atom in a covalent bond and is sometimes called an unshared pair or non-bonding pair
• Nonpolar bond


  A pair of valence electrons that are equally shared between two atoms in a covalent bond
• Electronegativity


  It measures the relative tendency of an atom to attract electrons to itself when chemically combined with another atom
• Atom


  It is the smallest unit of ordinary matter that forms a chemical element
• Molecular geometry
• If you add oil to water

  It will form two layers, not a homogenous phase
• Water and oil cannot be mixed even when heated
• Solubility


  The ability of a substance (solid, liquid, or gas) to dissolve in a given substance (solid, liquid, or gas)
• Miscibility


  The property of two substances to mix in all proportions, forming a homogeneous mixture. The term is most often applied to liquids
• The general rule about the solubility and miscibility of molecular compounds is "like dissolves like" or "like mixes with like"
• Water and oil do not mix because water is a polar molecule, while oil is nonpolar
• Intermolecular forces


  Forces that hold multiple molecules together and determine many of a substance's properties
• Intramolecular forces


  Forces that hold atoms in a molecule
• Intermolecular forces are weaker than intramolecular forces
• Intermolecular forces determine the state of matter (solid/liquid/gas) and physical properties such as melting/boiling point, while intramolecular forces determine chemical behavior
• The strength of intermolecular forces greatly affects the physical properties of substances such as boiling point, melting point, vapor pressure, surface tension, etc.
• Types of intermolecular forces

  • Ion-dipole
  • H-bonding
  • Dipole-dipole
  • Dipole-induced dipole
  • London forces of attraction
• Boiling point


  The temperature at which the vapor pressure and atmospheric pressure of a liquid substance are equal
• Melting point


  The temperature at which solid becomes liquid. At this point, the solid and liquid phases exist in equilibrium
• Surface tension


  The attractive force found in liquids which is responsible for pulling surface molecules in the rest of the liquid. Further, it minimizes the surface area
• Viscosity


  A measure of a liquid's resistance to flow. The greater the viscosity of a liquid, the more slowly it flows
• Vapor pressure


  The pressure exerted by the molecules that escapes from the liquid to form a separate vapor phase above the liquid surface
• Volatility


  The rate at which a substance vaporizes (changes from liquid to gas)
• Boiling point, melting point, viscosity and surface tension increase as the strength of intermolecular forces increases, while vapor pressure and volatility decrease with increasing strength of intermolecular forces