参考号：EM131125767
单位-SI（国际单位系统）和USC（美国习惯系统）
10-12 pico p
10-6 micro ?
10-3 milli m
10-2 centi c
103千克
106 mega M
Significant Digits and Rounding Numbers
To round numbers:
• If the digits to the right of the digit you are rounding are greater than five, round up.
• If the digits to the right of the digit you are rounding are less than five, round down.
• If the digits to the right of the digit you are rounding are exactly equal to five, round up or down so that the digit you are rounding to is an even number. (reference: R.C. Brinker, Elementary Surveying, International Textbook Company, 1969)
Examples: Round 234.5075 to the thousandths place 234.508 Round 0.0467 to the hundredths place 0.05
To determine the number of significant digits:
Define the following terms:
leading zero - zero to left of first non-zero digit in a number trailing zero - zero to right of last non-zero digit in a number
trapped zero - zero between two significant digits (zero or non-zero) Rules of significant digits:
1. all non-zero digits are significant digits
2.所有尾随的零到小数点的右边都是重要的数字
3.所有被困的零是重要的数字
4.all other zeros are not significant digits
Examples: 34608 - 5 significant digits 2110 - 3 significant digits
000456 - 3 significant digits 0.000456 - 3 significant digits
0.456000-6个显着数字4500.000-7个显着数字
Hints for problem solving
1. Write down on a single page every equation that is likely to be helpful for this problem set. Include conversion factors.
2.阅读每个问题几次直到你下stand what is being given and what is being asked. Sketch a figure if possible. Write down what you know and identify equations that will probably be useful.
A。Some people like to work backward; what do you need to determine the answer and how do you find it.
b。有些人喜欢锻炼；如果您知道这一点，您还能找到什么，这使您更接近最终答案。
C。Do not work backward from the final numeric answer. In real life the final answer is unknown. Use the final answer only to check your work when you are finished with the problem
Chapter 1 - Conservation of Mass
1.将5英里转换为毫米
2.Express 13 kg/ft3 in mg/m3
3. What is the mass of 1 mole of CO2? 1 mole = mass/ molecular weight of molecule - from periodic table (Table 2.1 on page 41) add up the molecular weights of all the elements in the molecule
4.质量(mg)是什么2.0 moles of O2?
5. There are 2.0 moles of potassium (as K+) in 10.0 liters of water.
A。有多少毫克钾？
b。How many mg of water are there?
C。在mg/m3中表达钾的浓度。
d. Express the concentration of the potassium in ppm.
6. Convert 1 ppm to mg/L.
1 ppm =(1克/ 106克水浓缩)*(1000克水/ 1 L H2O)* (103 mg conc/ 1 g conc)= 1 mg/L
7.找到1摩尔理想气体将在标准温度和压力（STP）处占据的体积
PV = nRT
n = 1摩尔，t = 273.15 k，p = 1 atm
V=nRT/P = 1 mol * .082056L.atm.K-1.mol-1 * 273.15K = 22.414L
1atm
8.在25 C和1 atm的空气中存在14.0 ppmv的CH4气体（甲烷）。
A。甲烷的百分比按体积百分比是多少？
b。What is the molecular weight of methane gas?
C。What is the concentration of the gas in mg/m3?
9. A proposed air quality standard for ozone (O3) is 0.08 ppmv. At the elevation of Denver, the pressure is about 0.82 atm. Express the ozone standard in ?g /m3 at that pressure and at a temperature of 15oC.
10. The federal Air Quality Standard for carbon monoxide is 9.0 ppmv. Express this as a percent by volume as well as in mg/m3 at 1 atm and 25 C.
11. A wastewater treatment plant receives 10 MGD (million gallons per day) of flow. This wastewater has a solids concentration of 192 mg/L. How many kilograms of solids enter the plant every day? (from Vesilind and Morgan, 2004)
12. Two stream, each with their own chloride concentration, combine. What is the concentration of chlorides out of a stream? Assume steady state, conservative conditions.
13. A stream carries water at a rate of 3000 L/min into a pond. A second stream adds an additional flow of 1500 L/min. What is the flow out of the pond?
16.一条具有400 ppm盐（保守物质）和25.0 m3/s上游的河流的农业排放量为5.0 m3/s，携带2000 mg/l的盐。盐在河里迅速混合。市政当局只是在下游撤出水，并将其与其他来源的纯净水混合在一起，以向客户提供不超过500 ppm盐的水。纯水与河水的比率应该是多少，F = Q5 /Q4？
7.汽车植物产生含有400 L/min的铝的液体废物。自动工厂的流出物排放到最初的流速为3.204 x 105 L/天，铝浓度为0.0020 mg/l。放电点下方是一个城镇捕鱼点。鱼对高于0.100 mg/l的铝浓度不耐受。为了将铝浓度保持在水流中或低于0.100 mg/l的流中，自动植物流出物中铝的最大浓度是多少？
18.应设计泻湖，以适应0.10 m3/s的非保守污染物的输入流量
19. Two ponds have decay. Assuming CSTR, what is pollutant concentration leaving each pond in mg/L and ppm?
20. A polluted stream has decay and a sewage outfall. Assume the pollution is completely mixed in the lake AND assume no evaporation or other water losses or gains. Find the
Steady-state concentration. What is the OUTLET concentration?
输入率=输出速率 + kcv q1*C1+ Q2*C2= q3*C3+kcV
Q1*C1+ Q2*C2=(Q1+Q2)*C3+kc3V
(5.0 m3/S* 10.0 mg/l +0.5 m3/s*100.0 mg/L) * 103L/m3=
（5.0m3/s + 0.5 m3/s）C*103L/m3+ 0.20/day* C*10.0 x106m3*103L/m3/(24 hr/day*3600s/hr) C3=3.50 mg/L23. (NOT USED THIS SEMESTER) Suppose the condition of the lake (in the above problem) is deemed unacceptable and it
is decided to suddenly divert the sewage outfall completely around the lake, eliminating it as a source of pollution. The incoming stream still has Q1 = 5.0 m3/s and C1=10.0 mg/L. With the sewage outfall removed, the outgoing flow Q3= 5.0 m3/s. Assuming complete mix conditions, find the concentration of pollution in the lake one week after the diversion and find the new final steady-state concentration
24.(NOT USED THIS SEMESTER) Find Q3 and C3 0.2 days after the smaller inflow (Q2= 25 m3/s) suddenly stops flowing. Assume a non-conservative pollutant with a decay rate of K=0.3/day
第2章 - 低温地球化学
1.平衡以下静态计量方程
二氧化碳 + H2O？H2CO3（碳酸）CO2 + H2O？H2CO3
Sio2 + H2O？Si（OH）4（Quartz to Silica）Sio2 + 2H2O？SI（OH）4
C4H10 + O2 ? CO2 + H2O (butane) 2C4H10 + 13O2 ? 8CO2 + 10H2O
2.证明质量在以下静压方程中是保守的：CH4 + 2O2？CO2 + 2H2O（甲烷）
3.将7.14 g的Halite（NaCl）样品完全溶于150 g的水。溶液的产生摩尔度是什么？
4.Suppose the concentration of benzene in a water sample = 0.017 mg/L. Express this concentration as mol/L. Benzene is C6H6
5. Consider a 1.67x10-3 M glucose solution (C6H12O6) that is completely oxidized to CO2 and H2O. Find the amount of oxygen (theoretical oxygen demand) required to complete the reaction.
6.计算325 g乙烷的理论氧需求，C2H6 2C2H6 + 7O2？4CO2 + 6H2O
325 g * (1 moleethane / 30 g) * ( 7 moleO2 / 2 mole ethane) * (32 g / 1 moleO2) = 1.21 x 103 g
7. The hydrogen concentration in a stream is 3.5 x 10-6 mol/L. What is the pH of the stream?
8.矿物荧光岩是CAF2。当将氟含量溶解在水中时，离子，氟化物的平衡浓度是什么？假设有固体的无限供应。
9.碳酸H2CO3，当溶解在水中时完全电离。计算含有52 mg/l碳酸的溶液的pH。
10. The volume of oxygen in air is about 21% by volume. Find the equilibrium concentration of O2 in water at 25 C and 1 atm. Recalculate it for Los Alamos with an elevation of 7500 ft above sea level.
11.工业废物的厌氧消化，主要乙酸，可产生二氧化碳和甲烷气体。如果每天的平均废物产生500 kg的CH3COOH，则计算每天在20 C下生产的二氧化碳的体积。[此反应没有氧气或水]
12. Nitrogen in a wastewater treatment plant is in form of ammonia and ammonium. Find the fraction of nitrogen in form of ammonia (strippable) as function of pH at 25 C. The value of K is 1.82x10-5.
13. Carbon dioxide dissolves in water to form carbonic acid which then disassociates into bicarbonate and hydrogen ions as follows:
二氧化碳 + H2O？H + + HCO3 K = 4.47 x 10
The amount of [HCO3 ] depends on the pH. Find the fraction of carbon ions that is bicarbonate as a function of pH. What would be the bicarbonate fraction for pH = 9.2?
14.计算在海拔2300 m海拔2300 m和20°C的水中溶解二氧化碳的平衡浓度。二氧化碳是大气的0.03％15。假设水与大气接触，其中含有0.03％的二氧化碳。pH = 7时碳酸氢盐的浓度是多少？假设在25 C处的海平面
16. Uranium 238 has a 1/2 life of 4.5 billion year. If the oldest rocks studied contain uranium 238 which currently has a mass of 54% of the original uranium, how old are the oldest rocks (lead 206 is the daughter product) ?
17. The half-life of cesium 137 is 30 years. If there were 500 g of cesium 137, how much would remain after 16.00 years (to 3-significant digits)?
18.放射性核素在15分钟内减少80％。它的半衰期是什么？
第4章 - 风险分析
1.从产生癌症的黄曲霉毒素中吃花生酱的风险。食品药品监督管理局将花生产品中的黄曲霉毒素限制在20 ppb中。在这个级别上，估计每天吃4汤匙会导致每10万人吃花生酱的癌症死亡 /年。假设美国有260,000,000人每天吃4汤匙花生酱，那么每年有多少人死于癌症？
What percentage of the yearly U.S. death rate from cancer would this be?
2.For every hour spent in a coal mine, a worker increases his mortality risk of dying by Black Lung Disease by 1 in 1,000,000. Suppose 600 coal miners work at the United Carbon Coal Mine for 40 hours each week, 50 weeks per year and 25 years. What percent of the coal miners will die from Black Lung Disease from working in the mine?
3.假设一个70公斤的人每天用氯仿浓度为0.10 mg/L（饮用水标准），每天每天喝2升水。氯仿具有效能因子= 6.1x10-3（mg/kg-day）-1。该人的上限终身癌症风险是什么？
4.Suppose drinking water contains 1.0 mg/L of toluene and 0.01 mg/L of tetrachloroethylene (C2Cl4). An adult drinks this water for 10 years. What is the hazard index? Tetrachloroethylene is probably carcinogenic. What is the lifetime risk to one person? Is this water safe?
5.假设马里恩的供水中有52 ppb的四氯化碳。使用PCB口服效能因子（文本的表4.9）和EPA建议的暴露因素（表4.10）。
A。一生中的CDI是什么？
b。What is the individual lifetime cancer risk for an adult residential consumer?
C。如果20,000人居住在马里恩（Marion），请估计供水中四氯化碳引起的额外癌症的数量。美国的平均癌症死亡率是每年每10万人193人。马里恩预计会有多少癌症死亡？您是否认为可以检测到饮用水中四氯化碳引起的其他癌症？
6. Find the DWEL for drinking water with chloroform that would result in a 10-6 risk. Chloroform has potency factor = 6.1x10-3 (mg/kg-day) -1.
8. The cancer risk caused by exposure to radiation is thought to be approximately 1 fatal cancer per 8000 person-rems of exposure (e.g. 1 cancer death if approximately 8000 people are exposed to 1 rem each). Living in a home with 1.5 pCi/L of radon is thought to cause cancer risk equivalent to that caused by about 400 mrem/yr of radiation.
A。Estimate the annual cancers in the U.S. caused by radon gas in homes. Assume to population of the U.S. is 300,000,000 people.
9. An underground storage tank has been leaking for years, contaminating groundwater and causing contaminant concentration beneath site of 0.30 mg/L. The contamination is moving with velocity = 0.50 ft/day toward public drinking water well 1 mile away. The half-life of contaminant = 10 years. The PF for the contaminant is 0.02 kg-day/mg. What is the life time cancer risk for one person who drank the water for 10 years ?
10. A factory releases a continuous flow of wastewater into a local stream, resulting in a carcinogen concentration of 0.1 mg/L in the stream below the factory. Suppose this carcinogen has an oral potency factor of 0.30 (mg/kg-day)-1 and that it is degradable with a reaction rate coefficient, k = 0.10/day. Assume that the stream is uniform in cross-section and has a velocity of 1 mile/hr. At a distance of 100 miles downstream, the town of Upton uses this surface water as its only source of drinking water. Estimate an Upton resident's residential lifetime cancer risk caused by drinking this water.