Assignment 3

CIV ENG 2B04 – Assignment 3 Dr. Zoe Li Due: 4:00pm October 20 th (Friday), 2023 1. [25] Originally, the Speedy Dry Cleaning Company buys one barrel (0.160 m 3 ) of dry cleaning fluid each month. Ninety percent of the fluid (i.e., 258.23 kg/month) was lost to the atmosphere and 10% remained as residue to be disposed of. Congress banned the production of the Speedy Dry Cleaning Company’s dry-cleaning fluid in 2000. They are using a new cleaning fluid. The new dry-cleaning fluid has one-sixth the volatility (in volume) of the former dry-cleaning fluid. The density of the new fluid is 1.6350 g/mL. Assume that the amount of residue (in volume) is the same as that resulting from the use of the old fluid and estimate the mass emission rate to the atmosphere in kg/month. Because the new dry-cleaning fluid is less volatile, the company will have to purchase less each year. Estimate the annual volume of dry-cleaning fluid saved (in m 3 /yr). 2. [15] A drainage basin has an area of 17,500 km 2 . If the average annual runoff is 252 m 3 /s and the average rainfall is 921 mm, estimate the evapotranspiration losses for the area in one year. How reliable do you think this estimate is? 3. [30] Radioactive waste from a clinical laboratory contains 0.28 µ Ci/L (microcuries) of 45 Ca. The half-life of 45 Ca is 152 days. Assume first-order decay. a. [10] How long must this waste be stored before the level of radioactivity falls below the maximum acceptable concentration of 0.01 µ Ci/L? b. [10] Radioactive waste can be stored in many ways, including deep well injection and above-ground storage. Deep well injection involves pumping the waste thousands of feet below the earth’s surface. Above-ground storage is in buildings in isolated areas, which is then guarded to prevent people from getting near the waste. What would be the risk factors associated with each of these storage methods? What could go wrong? c. [10] Which system of storage would you believe is superior for such a waste? 4. [30] The data in the table below represent the molar concentration of constituent X at various times in a reactor. a. [15] What order is this reaction? Show zero-, first-, and second-order graphs. b. [5] What is the rate constant? c. [10] Why might it be inaccurate to base your answer to the previous questions on only a few data points? Time (s) [X] (M) 0 7.52 100 5.23 200 3.48 300 2.40 400 1.61 500 1.12