CH217 - Homework

Versions Compared

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.
Comment: Migrated to Confluence 4.0

...

Gibbs, Jeff. "Green Nightmare: Burning Biomass is Not Renewable Energy." The Huffington Post. 17 Dec. 2009. Web. 23 Feb. 2010. <http://www.huffingtonpost.com/jeff-gibbs/green-nightmare-burning-b_b_395553.html>. 

 

The Gibb’s article gives an opposing view, explaining why biomass generated energy is not a renewable energy source.

 

MaineForest Service. MaineForest Service Assessment of Sustainable Biomass Availability. Rep. Maine State Government, 17 July 2008. Web. 24 Feb. 2010. <http://www.maine.gov/doc/mfs/pubs/pdf/biomass_memo_071708.pdf>.

 

The Maine Forest Service Report provided information regarding the current biomass of Maine's forests, and the sustainable yield for the forests.

 

MiddleburyCollege. "Biomass at Middlebury." The Middlebury Blog Network. Web. 24 Feb. 2010. <http://blogs.middlebury.edu/biomass/about/>.

 

The Middlebury site was used to obtain general as well as specific information regarding the use of biomass technology at MiddleburyCollege. This information was used to determine what would be necessary for Colby to use biomass technology.

 

National Alliance of Forest Owners. "Carbon Neutrality of Energy from Forest Biomass." Carbon Neutrality of Energy from Forest Biomass. NAFO (National Alliance of Forest Owners), 2009. Web. 23 Feb. 2010. <http://nafoalliance.org/carbon-neutrality-of-energy-from-forest-biomass/>.

 

The National Alliance of Forest Owners site provides background information in regards to the carbon neutrality of producing energy from forest biomass.

Sarah, Kim, Reuben, and Trevor

Homework 4 - Due 3/5/2010

Book Problems - Chapter 9: 4, 6, 9, 12, 13

Additional Problems

1.  Freon, CFC-12, is building up in the atmosphere at a rate of 1.4 %/year. If the current concentration of CFC-12 is 519 pptv (parts per trillion by volume), what is the net molar flux of CFC-12 to the atmosphere in one year? 

2. Calculate the maximum wavelength of radiation that could have sufficient energy to effect the dissociation of nitric oxide (NO). In what regions of the atmosphere would such radiation be available? (The bond energy of NO is 90.2 kJ/mol)

3. The Chapman mechanism of stratospheric ozone production was successful at predicting the shape of the stratospheric ozone concentration profile, but overestimated the ozone concentration.  We now understand that simple ozone models involving only O2, O and O3species are incomplete.  What are the major processes controlling the stratospheric ozone concentration profile (shape and concentration) and how have atmospheric emissions in the last 50 years modified the profile.  (HW Key )

Homework 5 - Due 4/7/2010

Book Problems 11: 2, 7, 9, 14, 13: 4, 7, 11,17

Additional Problem:  During a recent talk at the Maine Water Quality Conference, Professor Steve Kahl from UMO showed convincing evidence of decreased acid deposition to Maine based on decreasing sulfate concentrations in Maine lakes.  During the same 10 year period the nitrate concentrations have also decreased, but much more slowly.  Explain these findings in terms of the chemistry of “acid rain” including current regulations, atmospheric chemistry, and emission sources.

Homework 6 - Due 4/16/2010

Lake Problem Set I. 

Consider a lake of infinite horizontal dimension, a depth of 20 meters, and a thermoclineat 10 meters. The epilimnetic temperature is 25 oC.    The hypolimnetic temperature is 6oC.   Both layers are well mixed vertically. The alkalinity of the lake is 0.10 mM.

1) Calculate the equilibrium concentration of oxygen at depths of 5 and 15 meters in units of ppm and moles/liter.

2) If the average wind speed on the lake is 10 meters/second, what rate of net biological oxygen demand (moles/liter sec) is required to decrease the oxygen concentration to 90% of saturation at 5 meters?

3) Based on the biological oxygen demand, how long will it take the hypolimnion to go anoxic (<1 ppm O2)?

Key:  Lake problem 2010 O2 solubility.xls

Homework 7 - Due 4/23/2010

Lake Problem Set II. 

Consider a lake of infinite horizontal dimension, a depth of 20 meters, and a thermocline at 10 meters. The epilimnetic temperature is 25 oC.    The hypolimnetic temperature is 6o C.   Both layers are well mixed vertically. The alkalinity of the lake is 0.10 mM.

1) Calculate the pH of the epilimnion assuming it is in equilibrium with CO2 in the atmosphere.

2) Assuming that the phosphate concentration of the lake was 20 ppb (as P) at the time of the spring turnover, calculate the oxygen concentration in the lake at 5 meters  and 15 meters after all the P in the epilimnion is consumed by photosynthesis, settles, and is respired in the hypolimnion.

3) What is the pH of the hypolimnion after the event described in step 2 occurs?

4)  By how much will the nitrate in the hypolimnion increase after the event described in step 2 occurs?