Access to and use of the internet is assumed in answering all questions including general information , statistics, constants, and mathematical formulas required to solve problems. These questions are designed to promote inquiry and thought rather than just finding material in the text. So in some cases there may be several “right” answers. Therefore, if your answer reflects intellectual effort and a search for information from available sources, your answer can be considered to be “right.” 1. Look up proposals to restore the Hetch-Hetchy Valley in Yosemite National Park to its former state. How might this affect water supply to parts of California? What might be some benefits of restoration of this valley to its former state? 2. Look up and explain the significance of the name Mulholland in relationship to water. How did Mulholland affect history? 3. Paradoxically, pollution by a strong acid such as HCl of groundwater in contact with limestone (CaCO 3 ) can lead to an increase in the alkalinity of the water. Using chemical reactions, explain how this may occur. 4. Tests can be performed on water that show the presence of biochemical demand (BOD) and other tests that chemically oxidize organic matter to produce CO 2 can show total organic carbon (TOC). Applied to a particular sample of water, these two tests showed relatively high TOC and relatively low BOD. What does this say about the nature of the organic pollutants in the water? 5. Agricultural fertilizer normally adds nitrogen, phosphorus, and potassium to soil. Explain how fertilizer runoff into a body of water can lead eventually to increased biochemical oxygen demand pollution. 6. The development of the flameless atomic absorption analysis for mercury enabled very sensitive tests for this element around 1970 and showed suprisingly high levels of this toxic element in some fish samples. The inorganic chemistry of mercury suggests that mercury compounds should precipitate and settle into sediments where they are unavailable to fish. What, then was the explanation for the high mercury levels found in some fish around 1970? 7. Phosphate in the form of H 2 PO 4 - and HPO 4 2- ions is the substance usually removed from secondary sewage effluent to prevent excessive algal growth and eutrophication in receiving waters. Of several possible algal nutrients, why is phosphate chosen? Show with a chemical reaction the most common means of removal. 8. Membrane filtration processes can be very effective in removing residual BOD from secondary wastewater effluent. What does this suggest regarding the nature of contaminants responsible for the BOD? 9. By doing some search on the internet, gather information regarding the use of wastewater for irrigation. Is this a practice that is used and if so where does it usually take place? What are some of the benefits? What are some of the risks? 10. In Section 9.2 information is given about the total amounts of water on Earth and how much of it is in the solid form as ice, snowpack, and glaciers. Information is available on the internet regarding the heat of fusion of ice and the rate at which energy reaches Earth from the sun. From this information, estimate the length of time required to melt all of Earth’s solid water if all the solar flux received by Earth could go to that purpose. 11. Water is used for both its special solvent properties and its ability to absorb, transfer, and release heat energy. Explain on the basis of the characteristics of the water molecule how these two uses are related. 12. How far back into history does the use of waterpower go? Which civilizations were the first to use it? Explain why during the mid-1800s waterpower development slowed, only to start growing rapidly around the late 1800s and early 1900s. 13. What is Plaster of Paris? Show with a chemical reaction how water is employed as a chemical reagent in making objects from Plaster of Paris