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Published byMorgan Montgomery Modified over 9 years ago
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The Future (?) Data from past 100 years: CO 2 conc. has risen by 25% average temp. increase: 0.5-0.7 0 C Current: doubling the CO 2 conc. +1.8-6.3 0 C (2.5-10.4 0 F by 2100) CO 2 is a major part of the greenhouse effect Earth’s average temperature is increasing
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Shape of Molecules (3.3) Greenhouse gases: CO 2, CH 4, N 2 O, O 3, H 2 O, CFCs Not greenhouse gases: O 2, N 2, Ar Why the difference? Shape!
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VSEPR Lewis structures: 2D Reality: 3D Bonds are made of electrons Negatively charged Repel each other (still attracted to protons) Want to be as far apart as possible!
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Example: Methane CH 4 : tetrahedral C H H H H 109. 5 H H H H C
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Fig.3.7
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Fig.3.8
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Fig.3.9 “Trigonal Pyrimidal”
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Fig.3.10 “Bent”
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Fig.3.11 “Linear”
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Fig.03.12 “Bent”
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Light and Molecules (3.4) UVB, UVC: Bonds break IR: Can’t break (not enough energy) Can cause vibrations Shape HOW a molecule can vibrate Which wavelength? Bond strength & flexibility, atom masses
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Fig.03.13
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Fig.3.14
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What about O 2 and N 2 ? Do not absorb IR radiation IR does not cause vibration Can’t “trap” heat Not greenhouse gases
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Fig.3.16
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The Carbon Cycle Sect. 3.5
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Fig. 3.17 Where does CO 2 come from? Where does it go?
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Sources of CO 2 CaCO 3 (limestone) water Plants & animals Respiration/decay Volcanic vents CO 2 (natural)
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Consumption of CO 2 CO 2 Plants Respiration water H 2 CO 3 Pressure/time Fossil Fuels Mineral Dep.
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Fossil Fuel Contribution to Atmospheric CO 2 : 6-7 billion tons of carbon released ~ ½ goes to atmosphere Since 1860: – CO 2 conc. 290 ppm 375 ppm, – Increases ~1.5 ppm/year.
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Deforestation Adds CO 2 to air (burning/decay) Takes away a CO 2 remover (trees/plants)
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Excess CO 2 global warming Increase in atmos. CO 2 is a concern – 3.1-3.5 Gt of carbon/year How much CO 2 is added per year?
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Quantitative Concepts: Mass (3.6) How much does an atom weigh? Depends on the atom Standard: Carbon-12 Mass # Atomic #: 6 6p, 6n One Carbon 12 = 12 amu
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C 6 Carbon 12.01 Atomic # Symbol Name Atomic Mass
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Carbon: 3 isotopes Carbon-12: 98.89% Carbon-13: 1.11% Carbon-14: ~0.00% Average atomic mass for C = 12.01 amu What’s with the 12.01??? Atomic mass is an average of all carbon atoms
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NO carbon atoms weigh 12.01 amu Treat ALL carbon atoms as though they weigh 12.01 1 Tbs of carbon has about 6.022 x 10 23 carbon atoms – 602,200,000,000,000,000,000,000 Dealing with large numbers of atoms – Average is best
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