GEMS 160
March 3, 2006
• Today - Finish Ch. 7, review global warming
section 8.11-15.
• Ch. 7 problems due today, 5:00 pm. Answer
key posted to discussion board.
• Exam on Monday. Ch. 6, 7, 8.11-15, Chem
news presentations - optional start at 8:00
• Pick-up Ch. 6 homework and midterm info after
class
The crude oil in sample is
18%
11%
71%
0%
1.
2.
3.
4.
A pure compound
A mixture of oil and ethanol
A mixture of hydrocarbons
Ready for your car’s gas tank
Auto Pollution Solution
The crude oil is separated into
various components by
1.
97%2.
0% 3.
3% 4.
0%
Fermentation
Fractional distillation
Force of gravity
Filtration
Auto Pollution Solution
• Methanol
– Manufactured from various sources
• Wood, coal, natural gas, garbage
– Relatively corrosive
– Low energy content
– Toxic, produces formaldehyde as a by-product
• Ethanol
– Renewable energy, fermentation of grain crops
– Plants absorb CO2 - offset greenhouse gas buildup
• Photosynthesis
• 12 CO2 + 11 H2O + solar energy ==> C12H 22O 11 + 12 O2
–
–
–
–
Low energy content
Use as oxygenate in gasohol
Limited supply and relatively high cost
E85 and FFVs
Auto Pollution Solution
• Natural gas
– Clean burning, affordable
– Short driving range due to fuel storage criteria
– Non renewable
• Hybrid vehicle - gasoline and electric
• Fuel cells
– 2 H2 + O2 → 2 H2 O + energy in the form of electricity
– Only chemical product is water
1
The most common source of
hydrogen for fuel cells is
43%1.
H2O
37%2. CH4
3% 3. Photosynthesis
17%4. Concentrated from the atmosphere
http://www.epa.gov/fuelcell/basicinfo.htm#diagram
•
Fossil fuels - forms of potential energy
• Net reaction for formation of H2 at high
temperature
•
Energy released when C-C bonds are broken
•
Vehicle in motion - form of kinetic energy
• CH4 + 2 H2O => CO2 + 4 H2
•
How do fossil fuels acquire energy?
• What is of environmental concern here?
• Cost, convenience and environmental
impact - all are “tradeoffs”
• Ultimately a chemical solution
 Photosynthesis
 12 CO2 + 11 H2O + solar energy → C12H22O11 + 12 O2
 The opposite of combustion
•
CO2 sources and sinks; the carbon cycle
 Atmosphere, plants and oceans
•
Equal transfer rates between sources and sinks produce a
stable system, but rates are currently not balanced !!
http://www.oism.org/pproject/s33p36.htm
http://www.windows.ucar.edu/tour/link=/earth/climate/images/carboncycle_jpg_image.html
2
•
Global Warming
•
Gases that absorb infrared radiation
CO2
biomass burning
CH4
land fills, cattle and rice farming, coal mining,
petroleum refining, natural gas use
O3
burning plants, smog, engine exhausts
N2O
nitrogen containing fertilizers
•
Why? - they all have a change in the dipole of the
molecule when they vibrate or bend in certain ways.
•
What about water?
National Academy of Sciences 2001 report
Current warming does result largely from human activity
but that climate variations unconnected with human
behavior may also play a significant role in global
warming.
Some exam topics
Isomers, names, formulas, hydrocarbon
families, structure and properties - boiling
point, branching, molecular weight,
saturated/unsaturated, octane - octane
enhancers, combustion, catalytic converter,
crude oil and its products, distillation,
refining, greenhouse effect
3