BIOLOGY 171

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BIOLOGY 171 CHAPTER 3
Water and the Fitness of the Environment
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Polarity and Hydrogen Bonding
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UNIQUE PROPERTIES OF WATER
Cohesion Adhesion Capilarity Surface
Tension Water Transport in Plants
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Transport in Plants
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Surface Tension
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UNIQUE PROPERTIES OF WATER
Kinetic Energy Heat Temperature Calorie
cal Kilocalorie - Kcal
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Specific Heat

• Specificic Heart Heat required
• To raise the temp of a substance
• 1 degree C.
• High Specific Heat
• 1 cal/g/oC
• Iron .1 cal/g/oC
• Alcohol 0.6 cal/g/
• Helps moderate environmental
• temperatures.

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Heat of Vaporization

• Heat of Vaporization The amount of energy
  required to convert one gram of a liquid to a
  vapor.
• High Heat of Vaporization for Water
• 580 cal/g
• Cools living things
• Modifies the environment.

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UNIQUE PROPERTIES OF WATER
Water is most dense at 4oC
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UNIQUE PROPERTIES OF WATER
Water is the solvent of life.

• Solvent, Solute, Solution
• Hydration Shell
• Aqueous Solution
• Hydrophobic
• Hydrophilic

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Hydration Shell
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MOLARITY SOLUTE CONCENTRATION IN AQUEOUS
SOLUTIONS
Molecular Mass Mole Gram equavilent of the
molecular mass. Molarity Moles of solute per
liter of solution
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.5 Molar Solution of Sodium Chloride (NaCl)
.5 Molar solution is 1/2 mole (29.25g) of NaCl
dissolved in enough water to make 1L of
solution.
Na 23 Cl 35.5 58.5 Molecular Weight
NaCl A mole of NaCl is 58.5 grams.
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pH SCALE
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Moles
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DISSOCIATION OF WATER
H2O H2O H3O OH-

By Convention
H2O H OH-
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DISSOCIATION OF WATER
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pH

• - The negative log rhythm of the H
• concentration of a solution.
• - There is an inverse relationship
• between the H and OH-
• concentration of the solution.
• - pH scale ranges from 0 to 14.
• - A pH of 7 is neutral, meaning
• that the solution contains
• an equal number of H and OH-.
• 10-7 moles of H and OH-
• one ten-millionth mole per liter

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pH CONTINUED
- A pH value below 7 is an acid, while above
7 is a base. - Lower numerical values are more
acid while higher values are more basic. -
The difference in concentration of H differs
by 10 times between values, thus an acid of 5
has 10 times more H than an acid of 6.
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ACIDS, BASES AND SALTS
Acid - A hydrogen ion donor releases H and
absorbs OH- when dissolved in water, sour
taste. Turn litmus red. Base Released OH- and
absorbs H when dissolved in water, bitter
taste. Litmus blue. Buffer - A substance that
minimizes changes in H and OH- concentrations.
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Salt - A precipitate that results from the
mixing of an acid and a base.
Acid Base Water
Salt HCl NaOH
H2O NaCl
Acids and the Environment
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pH AND THE ENVIRONMENT

• Acid Rain Below 5.6
• Causes
• Impact
• Soil pH
• Soil Fungi
• Vascular Plants - Mineral Uptake
• Leached Minerals Calcium and
  Magnesium

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Acid Rain