Should we control a chemical that:
Causes excessive sweating and vomiting.
Is a major component in acid rain.
Can cause severe burns in its gaseous state.
Accidental inhalation can kill you.
Contributes to erosion. Decreases the effectiveness
of car brakes. Has been found in tumors of
terminal cancer patients.
What is the chemical?
Chapter 3Water and the Fitness of
the Environment
Question?
What molecule Is the most common In living Cells
Properties Of Water
Be ready and able to discuss several of the following properties.
Focus on definitions and examples.
Review water structure and H-bonds from Chapter 2.
Liquid Water Is Cohesive
Liquid Water is Adhesive
Water transport in trees uses Cohesion and Adhesion
Water Has A High Surface Tension
Water Has A High Specific Heat
Celsius Scale
Will be used for most of our temperature measurements.
Water Stabilizes Temperature
Water Has A High Heat Of Vaporization
Evaporative Cooling
Water Expands When It Freezes
Solids and Liquids
Water Benzene
Floats Sinks
Solid Liquid Gas
States of Matter
Result Aquatic life can live under ice.
Water Is A Versatile Solvent
Hydrophilic Materials
Without Water Life Would Not Be
Possible!!
Solution Concentration
Usually based on Molarity.
One Mole of each
Sulfur
Sugar
Copper Sulfate
Mercury Oxide
Copper
Sodium Chloride
Comment
AP Biology students should be able to calculate solutions in Molarity.
Dissociation of Water Water can sometimes split into
two ions.
In pure water the concentration
of each ion is 10-7 M
Adding certain solutes disrupts the balance between the two ions.
The two ions are very reactive and can drastically affect a cell.
Example:
For a neutral solution:
[H+] is 10-7
or - log 10-7
or - (-7)
or 7
Comment
[H+] + [OH-] = 14 Therefore, if you know the
concentration of one ion, you can easily calculate the other.
Summary
Be able to discuss the properties of water.
Be able to measure solution concentrations in Molarity.
Be able to work pH scale questions.