9.3 & 9.3.1 - PROPERTIES OF WATER

• Water has a chemical formula of H2O
• The chemical name of water is Dihydrogen oxide / Dihydrogen monoxide
• Covalent bonding occurs in order for the electrons to be stable.
• Hydrogen bonds are stronger than covalent bonds.
• Covalent bond - atoms share electrons in a molecule=

  Hydrogen bond - attraction between a positive and negative charge
• Covalent bond - atoms share electrons in a molecule
• It is when opposite ends have opposite electrical charges; imbalance in charge

  Polarity / polar molecule
• it is the outermost electron of atoms

  valence electron
• Oxygen - 6 valence electrons; partial negative charges

  Hydrogen - 1 valence electron; partial positive charges
• Oxygen is more electronegative than Hydrogen.
• Oxygen attracts electrons stronger.
• Hydrogen Bonds - one of the strongest intermolecular bonds.
• Cohesion - attraction of molecules of the same kind

  Adhesion - attraction of molecules of different kind
• (Adhesion) Water molecules are strongly attracted to glass molecules
• It is the upward motion of water through narrow spaces.

  Capillary Action
• .

  A) adhesion

  B) cohesion

  C) adhesion

  
• What makes water a good solvent?

  It can attract molecules of solute by its partial charge.
• The cohesive force between water molecules is so strong that it creates a surface tension that can resist an external force.
• It is the highest temperature wherein a liquid maintains its form. Any

  further addition of heat to this temperature will cause the liquid to evaporate.

  Boiling point
• boiling point of water

  100 degrees celsius
• When temperature continues to rise over the boiling point, the hydrogen bonds of water molecules will begin to break and will cause the water to evaporate.
• freezing point of water

  0 degrees celsius
• It is the temperature at which a liquid will start to solidify.

  freezing point
• Water molecules will form more hydrogen bonds and stronger ones when freezing.
• It is the property of water is able to absorb heat – without increasing much in temperature

  temperature moderation
• it is the amount of heat needed to change temperature and depends on the amount of substance

  heat capacity
• Why does it take a lot of energy to change the temperature of water?

  Water is very resistant to temperature changes and takes a long time to heat and cool with the STRONG HYDROGEN BONDS.
• amount of heat needed to transform liquid to gas

  heat of vaporization
• what is water's heat of vaporization in boiling point?

  2260 j/g
• it is when water at boiling point requires heat energy in order to evaporate; as it releases heat, the liquid water cools down

  evaporative cooling
• (a property of water) sweat evaporates by absorbing heat from the body

  perspiration
• solid - most dense, liquid - less dense, gas - least dense
• water is most dense at 3.89 degrees celsius
• Name the 13 properties of water:

  1. Polarity
  2. Cohesion
  3. Adhesion
  4. Capillary Action
  5. High boiling point
  6. Low freezing point
  7. Temperature moderation
  8. High specific heat capacity
  9. Vaporization and Heat of vaporization
  10. Evaporative cooling
  11. Perspiration
  12. Phases of matter and density
  13. low density of water as solid
• Polarity

  Imbalance in charge
• Cohesion

  Attraction of same molecules
• Adhesion

  Attraction of different molecules
• Capillary Action

  Upward motion
• High boiling point

  100 degrees Celsius
• Low freezing point

  0 degrees Celsius