NATS 89

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1. It is often pointed out that Canada is fortunate to have 20% of the world’s freshwater supply within its borders. In your own words, carefully explain why this statement, though not technically incorrect, is nevertheless very misleading from the perspective of the sustainable use of water resources. 2. In your own words, describe the fundamental sustainability problem faced by agriculture in the US, India, and China (among others). What is the key to long-term sustainability? 3. For this question you’ll make use of the website found at the following URL: https://waterfootprint.org/en/water-footprint/. Start by reading through the section titled ”What is a water footprint?” and then the one titled ”Personal water footprint”. Next, navigate to the extended water footprint calculator found at https://waterfootprint.org/en/resources/interactive-tools/personalwater-footprint-calculator/personal-calculator-extended/ and complete the form to estimate your own water footprint. Then answer these questions: a) How does your total personal water footprint compare to the world average of 1243 m3 ? What are the largest two components of your water footprint? Within the food component of your footprint, which two categories are the largest? Do any of these results surprise you? Explain, one way or another. b) Based on your specific results, what are the three most effective actions that you would be willing to take to lower your personal water footprint. Which of the footprint components would each of these actions most likely reduce? (You can use the footprint calculator to check if you wish.) Reflect honestly on how successful you are likely to be in making such an attempt to reduce your water use. 4. Solutions A and B have, respectively, a pH of 8.4 and 3.4. Which of the two solutions is the most acidic, and how much more acidic is it compared to the other one? 5. The bottom of Lake Pruitt, in which the water has a pH of 6.8, consists mostly of exposed limestone. As a result of renewed coal burning upwind of the lake, it starts receiving regular acid precipitation with a pH of 4.5. A reaction takes place between limestone (calcium carbonate, CaCO3) and hydrogen ions that produces carbon dioxide and water and is described by CaCO3 + 2H+ → CO2 + H2O + Ca2+. What can be expected to happen, qualitatively, to the lake’s pH during the next few years? Will it increase as acid loading continues, decrease, or stay roughly the same? Explain. 6. A large volume of raw sewage (untreated household waste) is accidentally released into an oligotrophic lake. In what order do the following events occur? • Algal bloom; • Decrease of dissolved oxygen concentration; • Increase of inorganic nutrient concentration; • Disappearance of fish Explain your reasoning. 7. In Scotland the Cruachan Power Station stores 10 million cubic metres of water in an elevated reservoir (it is a pumped-storage station). That water can be released to flow downhill and then through turbines, producing a maximum 440 MegaWatts of electrical power for up to 22 hours. The power station can go from zero to maximum output in as little as 30 seconds. Is such a facility well suited to supplying baseload power, or is it best used in some other role? Explain. 8. The electrical energy used to light a house might go through the following sequence of conversion steps (assuming the fuel resource to be coal). i) One tonne of coal is completely burned to produce steam in a boiler that has an efficiency of 85%; ii) The hot, high-pressure steam passes through a steam turbine that has an efficiency of 35%; iii) The spinning turbine drives a generator that has an efficiency of 97%; iv) The transmission lines from the generator to the house deliver electricity with an efficiency of 92%; v) That delivered electrical energy powers a LED light bulb that converts it into visible light with an efficiency of 40%. What fraction (expressed in %) of the primary energy in that original tonne of coal actually contributes to lighting the house? What happens to the rest of the energy? 9. You are a junior energy analyst at a large financial firm. The small nation of Slobovia has just announced the probable existence of a large deposit of tight natural gas beneath its central plain. You immediately start crunching the available numbers in order to update the company’s estimate of Slobovia’s natural gas reserve. However, after commending your analysis your immediate supervisor puts a hold on any update of the company’s figures. For what reason has she done this? What conditions will have to be satisfied before estimates of Slobovia’s natural gas reserve can be updated? [2 Marks] 10. The Coastal GasLink pipeline, now under construction in British Columbia, would see fracked natural gas shipped to the West coast for eventual transport to Asia. As you may be aware, it is being opposed by some indigenous groups in British Columbia, and has been criticized by many for enabling the continued use of fossil fuels and the associated carbon dioxide emissions. Describe the reasons why an environmentalist might nevertheless argue that the pipeline could result in lower carbon emissions and should be built. 11. Crude oil spilled into a large body of water immediately begins to undergo changes collectively called “weathering”. a) List and briefly explain two of the major processes involved in weathering of oil. b) For what reason(s) might a large crude oil spill in the Arctic be expected to have longer-lasting consequences? Explain in the context of weathering processes. 12). Butanol (C4H10O) is a biofuel that can be used, with no engine modifications, as a substitute for conventional gasoline. The complete combustion reaction for butanol reads C4H10O + 6O2 → 4CO2 + 5H2O. a) List the primary pollutants likely to be emitted by a butanol-burning internal combustion engine. b) What conditions would have to develop in the engine in order to see incomplete combustion of the butanol? How is the list of primary pollutants likely to change under these conditions? Explain. c) If the primary pollutants identified in a) are released into the atmosphere, then which secondary pollutants are the direct result? d) Suppose an internal combustion engine is modified to burn butanol in a pure oxygen environment (instead of air). Will this help to reduce primary pollutant emissions? If so, which ones and why? 13). This question asks you to track your use of electrical energy for ONE day. The basic steps are outlined below, and questions follow: • For ONE day, keep track of all of the electrical devices that you make use of and for how long. (eg. Microwave oven for 3 minutes; hair dryer for 5 minutes; TV for 90 minutes;…) Track only those devices over which you have direct control, so what you’ll have is a measure of your discretionary use. • Devices that are plugged in but “off” like TVs and chargers still consume a small amount of power – so-called “standby” or “phantom” power. Try to include these contributions. • Using either information read off of the device itself or published tables, identify the power draw of the device. (Cite your sources as necessary.) • Using the collected data, work out the electrical energy consumed by each appliance. (Recall that Energy = Power × Time; express time in hours and power in kilowatts to obtain energy in convenient units of kilowatt-hours.) • Although they aren’t required, you can include items like refrigerators if you wish following the suggestions in the supplementary document. Once you have collected all of the data, again just for ONE day, then you can start assembling a short report for inclusion in the assignment. a) Present a summary of your findings for that one day in table form (include the name of the device, hours used, power draw, and energy consumed). b) Which device(s) accounts for most of your electricity consumption? Does this make sense to you or is it a surprise? Explain. c) Do you think you can realistically reduce your discretionary consumption of electricity going forward? If so, describe how.

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