1. Water: Section C

2. Solubility Maximum quantity of a substance
that will dissolve in a certain
amount of water.
Factors Affecting Rate
Size of solute crystals
2. Stirring
3. Temperature

3. Types

4. Gases Solubility increases when the temperature decreases.
Depends more on pressure
Directly proportional
Increase pressure, solubility increases

5. Solution Concentration
Quantity of solute dissolved in a specific quantity of solvent
Expressed as
1. Graphs
2. Percents
grams of solute x 100
grams of solution

6. Adding Oxygen to Water
Aeration = oxygen mixes with water when water is unsettled.
Photosynthesis = green plants making sugars from CO2 in presence of sunlight
light
6CO H2O ----> C6H12O O2

7. Bacteria Using Oxygen in Water
Aerobic bacteria feed on solid wastes of larger animals and biodegradable waste produced by industry.
If lots of food for aerobic bacteria, bacteria thrive and multiply.
Large population uses more D.O.
Larger animals needing the D.O. are threatened.

8. How much D.O. needed?
Fish need an average of 4 ppm of D.O. in the water to survive.
If D.O. decreases, fish either migrate or die.

9. Temperature & Gas Solubility
Fish are “cold blooded” = body temp. changes with environment
Affects their metabolism
Each 10oC rise in water temperature will double their metabolism

10. Summer Bacteria and fish compete for D.O.
Warmer water dissolves less D.O.
Competition becomes severe
Fish kill can occur after long stretch of hot summer days.

11. Too Much O2? N2 dissolves along with the O2.
Gas bubble trauma may develop in fish.
It causes gas bubbles to form in the blood & tissues of fish.
The O2 can be used by the fish but the N2 bubbles block the flow of blood.
Fish can die within hours or days.
Can be diagnosed by dissection of gills.

12. Heavy Metal Ions

13. Heavy Metal Ions Toxic in small amounts
Enters the water through wastewater.
Come cannot be removed as waste by the fish so it builds up.
Difficult to detect and remove.
Must prevent from entering in the first place.

14. Heavy Metal Ions
Lead
Mercury

15. Lead Uses Pottery, auto batteries, solder, pesticides, paints
Used to be in paint to protect bridges from corrosion.
Lead pipes > iron pipes > copper/plastic pipes
Tetraethyl lead used to be added to gas to produce better fuel but entered atmosphere through exhaust.

16. Symptoms of Pb Poisoning
Headaches
Memory problems
Fatigue
Vomiting, diarrhea
Poor appetite
Slow reflexes
Reduced coordination

17. Can Lead Cause Death?
Most Pb that is ingested can be excreted in the urine.
Only becomes a problem when exposed to Pb continuously for a long period of time.

18. Mercury Uses Thermometers, thermostats, paints
Antiseptics, fungicides, pesticides
Today, most found as a result of industrial pollution (coal burning power plants and chemical factories)
Get into water and ingested by fish
Limit amount of fish eaten per week

19. Inability to concentrate
Mercury Symptoms
Muscle aches
Blurred vision
Depression
Inability to concentrate
Memory loss
Skin rashes

20. Mercury (cont.) As liquid – not dangerous As vapor – harmful
Mercury vapors from a single broken thermometer is enough to contaminate a whole room.

21. Acids, Bases & Salts

22. Acids Begin with H that can easily break away in when placed in water
< 7 on pH scale
Turn pink/red in most indicators
Examples
H2SO4 HCl H2C2H3O2

23. Bases End with a hydroxide group (OH) > 7 on pH scale
Turn blue in most indicators
Examples
NaOH KOH

24. Salts (Neutral) Neither characteristic (no H or OH) 7 on pH scale
Examples
NaCl K3P LiHSO3

25. Indicators Change colors when exposed to acids or bases Examples
litmus paper
cabbage juice
phenolphthalein

26. Neutralization When an acid and base react with each other, the result
becomes neutral (if they are
the same strength)

27. pH Scale
Neutral
Acid
Base 7 14

28. Testing for Acids/Bases Using Cabbage Juice
Name of Substance
Color
Acid/Base?

29. Molecules Contain nonmetallic elements
Electrons are shared = covalent bond

30. Polar
Unequal sharing of electrons creates polarity. (Shows a net charge)
Water is polar.
Other polar molecules dissolve easily in water.
Ionic substances also dissolve easily in water.

31. Nonpolar "Like dissolves like" Molecules with no net charge.
Don’t dissolve easily in polar solvents.
Will dissolve in nonpolar solvents.
"Like dissolves like"