Solids and Liquids

• Matter is anything that occupies space and has mass
• There are three states of matter: solid, liquid, and gas
• Solid:

  • Has a fixed structure
  • Shape and volume do not change
  • Atoms are tightly packed in an arrangement
• Liquid:

  • Distinguished by its malleable shape
  • Constant volume
  • Atoms are close together but not in a fixed arrangement
• Gas:

  • Made up of separate atoms
  • No fixed shape or volume
• Physical Change Example:

  • When liquid freezes (H2O) into a solid state (ice), it appears as a change
  • The change is only physical
  • The composition of the constituent molecules remains the same: 11.19% hydrogen and 88.81% oxygen by mass
• Water exists in three forms with different characteristic ways:

  1. Solid (ice)

  2. Liquid (water)

  3. Gaseous state (water vapor and steam)
• Classifications of Matter:

  • The Different Types Of Attractive Forces
  • Properties Of Liquids And Intermolecular Forces
  • Heat Transfer Involving Liquids
  • Properties Of Solids
  • Types Of Solids
  • Heat Transfer Involving Solids
  • Structure And Properties Of Water
  • Phase Diagram
  • Types Of Geometric Forms Of Crystalline Solids
• Add or Subtract Energy:

  • When energy is added, particles move faster
  • When energy is taken away, particles move slower
• The Different Types Of Attractive Forces:

  • Intramolecular bonds & intermolecular forces
• Intermolecular Forces vs Intramolecular Forces:

  • Intramolecular Forces are strong and act within the molecules
  • Intermolecular Forces are weak and act between molecules
  • Intramolecular Forces are not strongly affected by physical changes, while Intermolecular Forces are strongly affected by physical changes
• Intramolecular Forces:

  1. Ionic

  2. Covalent

  3. Metallic
• Intermolecular Forces:

  1. Ion-Dipole

  2. Dipole-Dipole

  3. Dipole-Induced-Dipole

  4. H-bonding

  5. Dispersion (London)
• Ion-Dipole:

  • Strongest of the weak forces
  • Ions attract polar molecules
  • Important role in dissolving ions in water
  • Enough of these can break crystal lattice
• Dipole-Dipole:

  • The attraction between two polar molecules
  • Electrostatic attraction between ends of dipole-dipole forces
• Dipole-Induced-Dipole:

  • Between polar and non-polar substances
  • Occurs when one molecule with a permanent dipole repels another molecule's electron, inducing a dipole moment in that molecule
• Dispersion or Van Der Waals:

  • Weakest intermolecular force
  • Occurs in all types of molecules
  • The sum of attractive or repulsive forces between molecules
• 1. Bonding:

  • Attractive forces between hydrogen attached to an electronegative atom of one molecule and an electronegative atom of a different molecule
  • Hydrogen needs to be attached to a highly electronegative atom like oxygen, fluoride, or nitrogen
• Properties Of Liquids And Intermolecular Forces:

  • Surface Tension
  • Viscosity
  • Capillary Action
  • Vapor Pressure
  • Boiling Point
• Surface Tension:

  • Water acts as if it has a "skin" on it due to extra inward forces on its surface
  • Measure of inward forces that must be overcome to expand the surface area of a liquid
  • The cleansing action of soaps is partly due to a lowering of the surface tension of water
• Viscosity:

  • The resistance of a liquid to flow
  • A highly viscous fluid flows slowly
  • Viscosity depends on the strength of intermolecular forces; stronger forces mean higher viscosity
  • Viscosity decreases with an increase in temperature
• Capillary Action:

  • Occurs when water goes up a narrow tube against the forces of gravity
  • Capillary action is how plants and trees transport water from the roots to leaves where photosynthesis occurs
• Vapor Pressure:

  • When liquid is placed in a closed container, the molecules that escape or evaporate from the liquid into the gas phase will cause pressure on the container
• Boiling Point:

  • Defined as the temperature at which the vapor pressure of a liquid is equal to the atmospheric pressure
  • Water has a boiling point of 100°C, meaning it changes from liquid to gas at this temperature
• Molar Heat of Vaporization

  • Specific Heat: the amount of heat necessary to raise the temperature of a substance by 1°C
  • Heat of Vaporization: the energy absorbed to convert a liquid to gas at its boiling point
• Properties Of Solids:

  • Melting or Freezing Points
  • Sublimation
• Sublimation is the process of passing directly from the solid to gas phase without passing through the liquid state
• Examples of substances that undergo sublimation include mothballs and dry ice
• Heat of Fusion is the amount of heat required to melt one gram of a solid at its melting point at a constant temperature
• Heat of Fusion is expressed in calories per gram or Kcal per mole (or kilojoules per mole)
• Water is the most common and abundant chemical compound on Earth
• Water covers approximately 75% of the Earth's surface and is necessary for all living organisms
• Pure water at room temperature is a colorless, tasteless liquid
• Water has the highest specific heat of liquids and solids except NH3
• Water has the highest heat of fusion of all molecular substances
• Water has the highest surface tension of all molecular solids
• Water has the highest thermal conductivity of all molecular liquids
• Water is a universal solvent, meaning it dissolves lots of substances
• In water, the solvent is the water itself, while the solute is the substance being dissolved
• Water can dissolve other polar molecules