Chemistry of Water

• Evaporation occurs when heat energy from the sun causes molecules to gain kinetic energy and escape into the air.
• Water can exist as ice, liquid, or gas (water vapor) depending on temperature and pressure conditions.
• The water cycle is the continuous movement of water between the Earth's surface, atmosphere, and oceans.
• Snowfall occurs when precipitation freezes at temperatures below 0°C.
• Runoff is the portion of precipitation that flows over land surfaces rather than being absorbed by vegetation or soils.
• The water cycle is driven by solar radiation and gravity, with evaporation occurring at the surface of bodies of water and condensation taking place in clouds.
• Water - inorganic molecule
• Water - universal solvent

  • inorganic molecule (doesn't have carbon)
  • biologically produced
  • covers 71% of the Earth's Surface
• • Characteristics of Water
  • Unsymmetrical Molecule (104.5 or 105 degrees)
  • Polar Molecule (partial positive and negative)
  • Electronegativity (tendency to attract atoms)
  • Universal Solvent (hydrophilic - water-loving; hydrophobic - water fearing)
• Density of Water - 1000kg/m3; 1Kg/L; 1g/mL; 1g/cm3
• Water Molecule

  A) Hydrogen Atom

  B) Oxygen Atom

  C) Covalent Bond

  
• The Scale of Water at Sea Level or 1 Atm

  A) 100

  B) 37

  C) 23

  D) 0

  
• Specific Heat of Water

  A) 4.184J/K-g

  
• Values on Specific Heat

  A) Heat of Fusion

  B) 2259 joules

  
• The Water or Hydrologic Cycle
• Water Cycle:

  1. Evaporation
  2. Transpiration
  3. Condensation
  4. Precipitation
  5. Run Off
• Evaporation is the change of state from a liquid to a gas.
• • Transpiration is the evaporation of water from the plants through the stomata.
  • Stomata are small openings found on the underside of the leaves.
• Condensation is the process by water vapor in the sky is changed into a liquid state. It may appear as clouds. Its also the opposite of evaporation.
• Water Cycle:

  A) evaporation

  B) stomata

  C) stomata

  D) underside

  
• Water Cycle:

  A) condensation

  B) liquid state

  C) clouds

  D) evaporation

  
• Water Cycle:

  A) Precipitation

  B) rain, hail, snow

  C) fresh water on earth

  
• Water Cycle:

  A) runoff

  B) runoff

  C) water

  D) precipitation

  
• Specific Heat:

  A) latent

  B) sensible

  C) 2.108

  D) 4.184

  E) 1.996

  
• solid to liquid - melting

  liquid to gas - evaporation

  gas to liquid - condensation

  liquid to solid - freezing

  solid to gas - sublimation

  gas to solid - deposition
• Heat of Fusion - 334j/g

  Heat of Vaporization - 2259j/g