Chapter 15-Water properties

• Hydrogen banding


  Water molecules are "pulled in" resulting in a dome-like shape of a water droplet
• Surfactant

  • Soap
• Vapor pressure


  Ability to escape the water's surface and evaporate
• High melting point
• Methane changes from a gas to a liquid at -161°C
• Surfactant lowers the surface tension of water
• Properties of water
• Floats insulator keeper writer
• Spherical drop of liquid

  Surface tension due to H-bonding
• Hydrgen bonding


  Inward pull of the molecules
• Allows aquatic life to survive
• Molecule water (H2O) and Methane (CH4) have similar masses
• Water becomes a gas at 100°C
• Hydrogen bonding in water
• Water absorbs a lot of heat
• Could account for the differences
• No hydrogen bonding in methane
• Vapor pressure of water is low
• Surface tension of water is high
• Framework collapses when melting

  Open framework
• Slows to evaporate
• Surfactant


  Interferes with H-bonding
• Solutions


  Homogenous mixtures
• Ionic and polar covalent compounds


  Will readily dissolve in water
• Solution


  Homogenous aqueous system that contains dissolved substances
• "Like dissolves like" (like polarities)
• Extremely ionic substances

  Cannot be solvated in water because their ions are too strong to be broken by the attractions exerted by the water
• Non-polar covalent compounds


  Such as methane, oil, and grease do not dissolve in water
• Water has a partial + and a partial - (dipole) side

  The ionic compound breaks up
• NaCl is placed in water

  Collisions occur
• Solvent


  The liquid part of a solution
• Solute


  The dissolved substance
• Solvation


  The process of a solvent dissolving a solute and the solute being dispersed in the solvent
• Water molecules


  Move continually because of their kinetic energy
• Water


  Considered to be the universal solvent
• Solute (Na' Cl) ions

  Surrounded by the water molecules
• Solvents and solutes


  Can be solid, liquid, or gas
• Electrolytes


  Compounds that conduct an electric current. Oxides/bases
• Conduction of electricity


  Requires mobile ions in solution or in a molten state
• Nonelectrolytes


  Do not conduct electricity. Includes molecular substances with no ions involved.