Dr. Casey Name: ______________________Exam 3Spring 2002 Signature: ______________________Chem. 104Honor Statement: By signing this exam, you indicate that you have neither given nor received aid from any unauthorized source.Answer each question in the space provided. If you need more space, use the back of the sheet. All work must be shown to receive partial credit. You have until the regularly scheduled end of class to complete the exam. Good luck!1. a. Phosphorus can occur in several different forms in the environment. How do these forms of P differ in their availability as a nutrient?b. Explain the role of physical location on the availability of phosphorus as a nutrient.c. The forms and availability of nitrogen differ significantly from those of phosphorus. Which form of nitrogen is biologically unavailable? How do unavailable forms of phosphorus differ from nitrogen in form and location?2. Predict what will happen in the following scenario. Give reasons for your answer.A wetland (with anaerobic soils) is drained and used as farmland (agricultural soil is aerobic). The farm requires applications of PO43- fertilizers. After 25 years the farmer sells the land to a nonprofit organization that wants to convert the farm back to a wetland.In your answer, consider the dynamics of iron in this system and the implications on PO43-.3. If nitrogen is not present in gasoline, how does combustion of gasoline in automobiles contribute to the formation of HNO3 in acid rain? Be specific.4. List two environmental/health problems that occur as a result of burning coal that contains sulfur (include the specific sulfur compounds that are responsible).5. a. Explain how the greenhouse effect works in terms of an actual greenhouse (made of glass).b. Explain the similarities between a greenhouse made of glass and the greenhouse effectin the earth’s atmosphere.6. Identify the following statements as true or false.___________ a. Average global temperature is increasing.___________ b. Measured increases in temperature are due solely to increases in CO2___________ c. The greenhouse effect is a natural phenomenon without which earth’s temperature would average –20 C.___________ d. It is a scientifically certain fact that CO2 can retain heat.___________ e. CH4, N2O and CO2 have about the same ability to retain heat.7. What is the general trend indicated by the following graph? What causes the oscillating pattern in CO2