+ All Categories
Home > Documents > Option E: Environmental chemistrylorenowicz.weebly.com/.../4/...environmentalchem2.pdf · E8 Waste...

Option E: Environmental chemistrylorenowicz.weebly.com/.../4/...environmentalchem2.pdf · E8 Waste...

Date post: 11-Jun-2020
Category:
Upload: others
View: 8 times
Download: 0 times
Share this document with a friend
15
September 09, 2011 E8 Waste E7 Soil E6 Water treatment E5 Dissolved oxygen in water E4 Ozone depletion E3 Greenhouse effect E2 Acid deposition E1 Air pollution Option E: Environmental chemistry TODAY!
Transcript
Page 1: Option E: Environmental chemistrylorenowicz.weebly.com/.../4/...environmentalchem2.pdf · E8 Waste E7 Soil E6 Water treatment E5 Dissolved oxygen in water E4 Ozone depletion E3 Greenhouse

September 09, 2011

E8 Waste

E7 Soil

E6 Water treatment

E5 Dissolved oxygen in water

E4 Ozone depletion

E3 Greenhouse effect

E2 Acid deposition

E1 Air pollution

Option E: Environmental chemistry

TODAY!

Page 2: Option E: Environmental chemistrylorenowicz.weebly.com/.../4/...environmentalchem2.pdf · E8 Waste E7 Soil E6 Water treatment E5 Dissolved oxygen in water E4 Ozone depletion E3 Greenhouse

September 09, 2011

Page 3: Option E: Environmental chemistrylorenowicz.weebly.com/.../4/...environmentalchem2.pdf · E8 Waste E7 Soil E6 Water treatment E5 Dissolved oxygen in water E4 Ozone depletion E3 Greenhouse

September 09, 2011

Sun light coming in: Visible light Sun reflected out: IR

Equilibrium: light coming in = light going out

Therefore, the temperature on earth stays the same.

However, the greenhouse gases allows the visible light to come in, but absorb the IR light going out and reradiate back on the earth.

This way, light coming in > light going out.Therefore, the temperature on Earth is increasing gradually.

Page 4: Option E: Environmental chemistrylorenowicz.weebly.com/.../4/...environmentalchem2.pdf · E8 Waste E7 Soil E6 Water treatment E5 Dissolved oxygen in water E4 Ozone depletion E3 Greenhouse

September 09, 2011

CH4: Anaerobic decay of organic matter caused by intensive farming

H2O: Evaporation of oceans and lakes

CO2: Combustion of fossil fuels and biomass

N2O: Artificial fertilizers and combustion of biomass

CFCs: Refrigerants, propellants, foaming agents, solvents

Heat trapping effectiveness

not very effective

not very effective

effective

very effective

the most effective

Page 5: Option E: Environmental chemistrylorenowicz.weebly.com/.../4/...environmentalchem2.pdf · E8 Waste E7 Soil E6 Water treatment E5 Dissolved oxygen in water E4 Ozone depletion E3 Greenhouse

September 09, 2011

Page 6: Option E: Environmental chemistrylorenowicz.weebly.com/.../4/...environmentalchem2.pdf · E8 Waste E7 Soil E6 Water treatment E5 Dissolved oxygen in water E4 Ozone depletion E3 Greenhouse

September 09, 2011

Good ozone found in stratosphere. It protects us from UV light.Bad ozone found at ground level and formed from sun and VOC's. Results in smog

FREE RADICAL = VERY REACTIVE

Page 7: Option E: Environmental chemistrylorenowicz.weebly.com/.../4/...environmentalchem2.pdf · E8 Waste E7 Soil E6 Water treatment E5 Dissolved oxygen in water E4 Ozone depletion E3 Greenhouse

September 09, 2011

CFCs:

The most common CFC is CFC-12 : dichlorodifluoromethane CCl2F2

Also known as freon, used for refrigerants propellants for aerosols, foaming agents for expanding plastics, and cleaning solvents.

Oxides of nitrogen (NOx): formed from internal combustion engines, power stations, and jet aeroplanes.

Page 8: Option E: Environmental chemistrylorenowicz.weebly.com/.../4/...environmentalchem2.pdf · E8 Waste E7 Soil E6 Water treatment E5 Dissolved oxygen in water E4 Ozone depletion E3 Greenhouse

September 09, 2011

CFCs destroy the ozone layer because the UV light breaks the relatively weak C-Cl bond.This allows the formation of Chlorine radicals which reacts with the ozone molecules.

Alternatives must have similar chemical properties but not contain a bond that can be broken by UV to form radicals.

The properties required are: low reactivity, low toxicity, and low inflammability, as well as no weak C-Cl bonds. They should not absorb IR radiation as well, or they will act as greenhouse gases.

The alternatives are: hydrocarbons, fluorocarbons, and HFCs.

Page 9: Option E: Environmental chemistrylorenowicz.weebly.com/.../4/...environmentalchem2.pdf · E8 Waste E7 Soil E6 Water treatment E5 Dissolved oxygen in water E4 Ozone depletion E3 Greenhouse

September 09, 2011

Page 10: Option E: Environmental chemistrylorenowicz.weebly.com/.../4/...environmentalchem2.pdf · E8 Waste E7 Soil E6 Water treatment E5 Dissolved oxygen in water E4 Ozone depletion E3 Greenhouse

September 09, 2011

Try some problems!

Page 11: Option E: Environmental chemistrylorenowicz.weebly.com/.../4/...environmentalchem2.pdf · E8 Waste E7 Soil E6 Water treatment E5 Dissolved oxygen in water E4 Ozone depletion E3 Greenhouse

September 09, 2011

BOD is a measure of the dissolved oxygen (in ppm) required to decompose the organic matter in water biologically (in a certain volume of water, at a certain temperature).

Water that has a high BOD without the means of replenishing oxygen will rapidly not sustain aquatic life.

Usually you need about 5 ppm to support life, but it varies.

Page 12: Option E: Environmental chemistrylorenowicz.weebly.com/.../4/...environmentalchem2.pdf · E8 Waste E7 Soil E6 Water treatment E5 Dissolved oxygen in water E4 Ozone depletion E3 Greenhouse

September 09, 2011

If sufficient oxygen is present, organic material will decay aerobically, and oxides and oxyanions are produced.

Anaerobic decay involves organisms that do not require oxygen. The products are in reduced form, and are often foul smelling and toxic.

Page 13: Option E: Environmental chemistrylorenowicz.weebly.com/.../4/...environmentalchem2.pdf · E8 Waste E7 Soil E6 Water treatment E5 Dissolved oxygen in water E4 Ozone depletion E3 Greenhouse

September 09, 2011

Nitrates, and phosphates (waste from intensive farming, artificial fertilizers, detergents) accumulate in lakes. They act as nutrients and rapidly increase the growth of algae and plants, called an algae bloom.

--- Lots of detergents are now being pitched as "eco friendly" since they are phosphate free and don't contribute to this problem.

Normally, when plants and algae die they decomposes aerobically to form CO2 and water. However, if the growth is excess, then anaerobic decomposition will occur due to the lack of oxygen in water. The products not only smells bad but also poisons the water. As a results, more species with die, and more anaerobic decomposition will happen, and the lake is devoid of life.

Page 14: Option E: Environmental chemistrylorenowicz.weebly.com/.../4/...environmentalchem2.pdf · E8 Waste E7 Soil E6 Water treatment E5 Dissolved oxygen in water E4 Ozone depletion E3 Greenhouse

September 09, 2011

Thermal pollution - a change in temperature of an environment due to anthropogenic means.

The solubility of oxygen in water is temperature dependent. As the temperature is increased, the solubility drops. At the same time the metabolic rate of fish and other organisms increases, so the demand for oxygen also increases.

Same problem is caused by people cutting down too many trees near a lake, so that the shade is reduced and the temperature increases.

Many industrials use water a coolant (cheap) and they just discharge the heated water back to the sea/ocean. If the water is too cool, fish also may die off.

Page 15: Option E: Environmental chemistrylorenowicz.weebly.com/.../4/...environmentalchem2.pdf · E8 Waste E7 Soil E6 Water treatment E5 Dissolved oxygen in water E4 Ozone depletion E3 Greenhouse

September 09, 2011


Recommended