1. Chemistry Review

2. Radioactivity
If an atom is unstable, there may be a spontaneous release of material from the nucleus as it decays
Half-Life= rate of decay (the time it takes for ½ of the original amount to decay)
Environmental Significance: Damages the DNA of living organisms
Nuclear Energy/ Chernobyl/ Fukishima

3. Ionic Bond Definition Notes Examples
Bond between a metal and a non-metal
Transfer of electrons
Notes
Ions will dissociate in water
Examples
NaCl

4. Covalent Bond Definition Notes Examples Bond between two non-metals
Shared electrons
Notes
will not dissociate in water
Examples
Sugar, methane

5. Hydrogen Bond Definition Notes Example
Not really a bond but an attractive force between molecules
Notes
hydrogen bonding responsible for special properties of water
Example
Water, bases of DNA

6. Surface Tension Definition Environmental significance
Cohesion of water molecules at the surface
Attraction between the water molecules
Environmental significance
Aquatic insects can sit on the surface of water

7. Capillary Action Definition Environmental Significance
Adhesion of water molecules to another surface
Water may be able to move upward
Environmental Significance
Movement of water up stems of plants and trees

8. Heat Capacity Definition Environmental Significance
Water is slow to change temperature
Environmental Significance
Organisms are not exposed to extremes
Regulates climate

9. Freezing Expansion Definition Environmental significance
Water expands when it freezes
Therefore, solid is less dense than liquid and floats
Environmental significance
Ice forms on top of the lake creating an insulating barrier keeping heat trapped under the ice---beneficial to aquatic organisms

10. Solvent Definition Environmental Significance
Water is the universal solvent
Environmental Significance
This allows for nutrient, minerals, compounds to be transported throughout the cell
Pollutants are also dissolved and then distributed through water systems

11. WHY??
Water is POLAR!
Hydrogen bonding occurs!

12. pH Notes

13. Definitions
pH is the logarithmic expression of the hydrogen ion (H+) concentration
Acids are compounds that release hydrogen (H+) ions in a solution
Bases are compounds that release hydroxide (OH-) ions in a solution.

14. pH Scale

15. Environmental Significance
Living organisms function best at a neutral (7) or slightly alkaline (7.5) pH.
Strong acids and bases can interfere with biological processes of living organisms.
Acids leach toxic metals from the soil—creating toxic conditions for organisms

16. pH Scale

17. Environmental Scientists
Measure the pH of-
Soil
Water (lakes, oceans, rivers)
Rain
It is an abiotic factor that significantly impacts the biotic world!

18. The BIG question!
What is the difference between the numbers on the pH scale?
How much more acidic is a substance with a pH of 2 versus 3?
10X
What is the difference between a pH of 4 and 8?
10,000X

19. Carbohydrates Elements---CHO ROLE---energy
Sugars are created by photosynthesis

20. Lipids
Elements- CHO
ROLE: stored energy, cell membrane, hormones

21. Proteins Elements----CHON ROLES--- building blocks is amino acids
tissues, enzymes, cellular transport

22. Nucleic Acids Elements---CHNOPS
DNA- RNA----transfer genetic information