Assgn 1 - DEPARTMENT OF CIVIL ENVIRONMENTAL ENGINEERING...

Info icon This preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
D EPARTMENT OF C IVIL & E NVIRONMENTAL E NGINEERING C IV E 221 E NVIRONMENTAL E NGINEERING F UNDAMENTALS ASSIGNMENT NO. 1 D ATE HANDED OUT : J AN 23, 2012 D ATE DUE : F EB 1, 2012 ( IN ASSIGNMENT BOX BY 4:00 PM ) 1. A solution made up with calcium carbonate is initially supersaturated with Ca 2+ and CO 3 2- ions, such that the concentrations of each are both 1.35×10 -3 M. When equilibrium is finally reached, what is the final concentration of calcium? (Assume that the temperature is 25 ºC, pK s =8.34, CaCO 3 (s) Ca 2+ +CO 3 2- ) 2. What is the pH of a water sample that, at 25ºC, contains 0.5 mg/L of hypochlorous acid (HOCl). Assume that [H + ]=[OCl - ] at equilibrium and ignore the dissociation of water. (Given pK a =7.54, HOCl H + +OCl - ) 3. A solution of acetic acid is prepared in water by adding 12g of acetate acid to a volumetric flask and bringing the volume to 1L with water. The final pH is measured to be 5. What are the concentrations of acetate and acetic acid in solution? (Assume that the temperature of the solution is 25 ºC, pK a =4.75, CH 3 COOH H + +CH 3 COO - ) 4. Calculate the alkalinity (in milligrams per liter as CaCO 3 ) of a water (pH=9.43) containing 120 mg/L of bicarbonate ion and 15 mg/L of carbonate ion. 5. Supplementary Reading - Microbial Biology: Microbiology's Scarred Revolutionary (a) What are Carl Woese's three domains? (b) What evidence led Carl Woese to propose that archaebacteria should be classified separately from other prokaryotes? (c) In the article, it reads “Carl Woese revised the tree of life and started a new age in microbial biology by recognizing a third domain of life —but he paid the price for his radical ideas”. Why? Additional questions (not to be handed in) 6. Calculate the molarity and normality of the following: (a) 100mg/L Ca(OH) 2 (b) 80μg/L HNO 3 7. A magnesium hydroxide solution is prepared by adding 10.00 g of magnesium hydroxide to a volumetric flask and brining the final volume to 1.00L by adding water buffered at a pH of 7.0. What is the concentration of magnesium in this solution? (Assume that the temperature is 25 ºC, pK s =21.9, Mg(OH) 2 (s) Mg 2+ +2OH - )
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
8. The pH of a finished water from a water treatment process is 10.74. What amount of 0.02N sulfuric acid, in milliliters, is required to neutralize 1 L of the finished water, assuming that the alkalinity of the water is zero? 9. The concentration of oxygen in the atmosphere is approximately 20.9% by volume. Oxygen, however, is only slightly soluble in water, and its solubility is a function of temperature. As temperature increases, oxygen solubility in water decreases. For many aquatic systems that rely on the presence of oxygen, this poses a potential problem during summer months, when both temperature and the rate of biological activity are at their highest. Use Henry’s law to estimate the maximum oxygen concentration available to aquatic life during both summer and winter months, assuming 1 atm of pressure. Assume that average winter and summer high temperature are C and C, respectively. The H enry’s law constant for o ygen in water is . atm mol at C and .
Image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern