Tuesday, September 3, 2013

September 3rd

VI. H2O
  D. Stores Heat - allows organisms to maintain heat more efficiently.
  E. High heat of Vaporization - allows for evaporative cooling. (sweat)
  F. H2O is most dense at 4 degrees Celcius (frozen water is less dense than liquid water)
      -Spring Ice-off is very important for the ecosystem in a lake, it causes turnover which brings nutrients up from the bottom and jump-starts food chains. This also happens in the fall.
  G. pH - proportion of H+ ions to OH- ions in a solution.
       H2O ionizes: H2O=H+ + OH-
       Pure H2O   H+ = OH-    pH 7 is Neutral
       Pure H2O + HCl     H+ > OH-    pH < 7 to 0 - Acidic
       Pure H2O + NaOH     H+ < OH-    pH > 7 to 14 - Basic or Alkaline
       Caustic - because the pH is not 7 (neutral), either (+) or (-) ions will be pulled from a substance (a nail, as an example) and it will dissolve. Going in either direction from 7 (a neutral pH) is equally caustic.
       Buffers - any chemicals that bond to either H+ or OH- that neutralize pH.

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