Chapter 1

Why is there is there air?


Composition - OH

Atmospheric Pressure -OH
*Graph assignment - *

Pollutants - OH (Table 1.2)

Reading and Interpreting Tables


2% means 2 parts per hundred

2/100

In the case of atmospheric CO2
.036% .036/100

Parts per million x/1,000,000

Set up a ratio:
.036/100 = x/1,000,000
x=360


Read Appendix 2

Classifying Matter

Mixture - Physical combination of two or more substances (air)

Chemical elements - substances that CAN NOT be broken down into simpler stuff by chemical means (Oxygen)

Chemical Compound - a pure substance made up of two or more elements in a fixed, chemical combination & composition (water, carbon dioxide)


USING THE PERIODIC TABLE


Atom- smallest unit of an element that can exist as a stable, independent entity.

Chemical Formulas - symbolic representation of the elementary composition of chemical compounds (H20,H2)
Molecule - combination if a fixed number of atoms, held together by chemical bonds in a certain geometric arrangement.

Chemical Reactions & Equations


Chemical reaction - a process whereby substances (reactants) are transformed into different substances (products).

Chemical Equation (a model)


Reactant ----------->Product (-------->) “is converted to”, “yields”

TABLE 1.6 PG.17


Combustion of a Hydrocarbon

CH4 + O2 ---> CO2 + H2O
ALWAYS
Hydrocarbon + O2 ---> CO2 +H2O


BURNING

In Chem we call it combustion. ALWAYS assume total combustion unless I tell you otherwise!!


CH4 + O2 --->

C3H8 + 02 --->

C3H8 + 5O2 ---> 3CO2 + 4H2O


YOUR CAR


C8H18 + O2 --->


2C8H18 + 25O2 ---> 16CO2 + 18H20


BUT
If we don’t get enough O2

2C8H18 + 17O2 ---> 16CO + 18H2O

Air Quality


Deadly Fog ---> New Stephen King Novel

1. Coal --> S 1-3%

2. Smokestacks --> hi vs. lo

3. Fine Particles

4. 2SO2 + O2 ---> 2SO3 (Slow)

Catalyze - increase the rate of reaction

Aerosol - liquid droplets stay suspended in air (they are tiny --> fog)

5. H2O + SO3 ---> H2SO4
The combination of separate components working together is greater than the summative effect of each individually
Synergism



Your, Mine, Our Car


Octane +
O2 ---> CO2 + H2O
if complete combustion otherwise


---> CO + CO2 + H2O + xx
1. Not enough O2
2. Not enough time


So your catalytic converter

2CO + O2 ---> 2CO2

Urban air pollution


US vs. world
we aren’t the best but we’re not the worst


Photochemical smog

Volatile Organic Compounds (VOCs) - these may be the bane of the next generation

NO, NO2 in tables NOx
React with unburned gas to form ozone
(O3)
Sunlight provides the Energy (E)


Risks - Taking them and Assessing them

risk assessment
1. toxicity - amt. that is needed to do “damage” vs. LD50
10 ppb vs 10 pph

2. Exposure
a. Concentration in air (or?)
b. Time exposed
c. rate