Suggested Announcements
problems from Chapter 3 (pgs 164 - 169) 4, 5, 8, 15a, 20, 25, 27, 37, 41 Thursday we will spend much of the class in a policy debate. Nobel Peace Prize this year was for awareness of Global Warming
What about compounds?
When we have a compound with several atoms per molecule, we must calculate its molar mass. O3 ---> If I have a mole of ozone, I have 6.02x1023 ozone molecules. How many total O atoms are there?
Molar mass of a compound
1 mole of O atoms = 15.9994 g 1 mole of O3 has 3 moles of O atoms 1 mole of O3 = 3 x 15.9994 g =
Another example
Calculate the molar mass of CO2 C 2O -> 2(15.9994) = CO2
Your Turn
Calculate the molar mass of methane, CH4 4 x 1.008 + 1 x 12.011 = 16.04 g Calculate the molar mass of SO2 1 x 32.06 + 2 x 16.00 = 64.06 g
Who cares?
Provides a way to estimate our personal contribution. (3.28) "A clean burning engine ... will emit about 5 pounds of CO2 for every gallon of gasoline it consumes." Is this right?
How to know
Assume gasoline is C8H18 2C8H18 + 25O2 --> 16CO2 + 18H2O 1 gallon C8H18 weighs 2620 g how many moles is this? How many moles of CO2 are formed? How much does this weigh?
Consider the statement
The average American car driven the average American distance - 10,000 miles - in an average American year releases its own weight in carbon into the atmosphere.
How we do know global implications?
Climatic modeling must include --Earths energy balance Greenhouse gas concentration Atmosphere AND oceans
Forcings
Term used by climate scientists to describe factors that affect annual global mean surface temperature. Larger computer models include more forcings. Because it's a model, the different forcings can be added to "see" their effect
Complications?
Size of the planet - divide into regions (typically cubes 100 miles or more a side) sun spots or flares changing air patterns (el nino') volcanic activity - soot in the air ice sheets or cloud cover
Even worse complications
Feedback loops exist Oceans and CO2 Competing factor Which is correct?
Run computers to solve the equations
assume normal volcano activity and sun spot activity calibrate by going back i...