Chemistry_exam_Spr_2006_solutions_v1

Chemistry_exam_Spr_2006_solutions_v1 - Exam #1 Chemistry...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon
Background image of page 1

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

View Full DocumentRight Arrow Icon
Background image of page 2
Background image of page 3

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

View Full DocumentRight Arrow Icon
Background image of page 4
Background image of page 5

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

View Full DocumentRight Arrow Icon
Background image of page 6
Background image of page 7
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Exam #1 Chemistry Review EVEG 3110 Spring 2006 Multiple Choice (5 pts each, choose best answer) 1. 2. 6. Units associated with chemical dosage rate a) liters% g/min c) kilograms d) a or c. The concept of equivalent weights allows chemists to compare of different ionic compounds or elements to the hydrogen ion ...a) weight b) diameter W reactivity d) composition The equilibrium concentrations of ions in water is entirely predictable since it is fundamentally controlled by a) molecular weights,‘ random molecular collisions c) water molecules d) oxygen molecules. All organic compounds contain covalent bonds of a) calcium, b) phosphorus, w carbon, (1) silicon. Swamps tend to have. low b) high, 0) neutral d) no pattern here... pH levels a reflection of the decay processes that dominate the system. Sodium bicarbonate is a commonly found in a) surface waters b) baking soda, 0) tooth paste fl) all of the above Ratio of the H+ ion concentration at pH 6 as compared to 8: a) 2 b)20 & 100 d) 0.01 Addition of chlorine in the form of HOCL (hypochlorous acid) will tend to ...a) raise, $1 lower, c) have no effect on ...the pH. Short Answers (10 points each, be concise) 9. When an environmental engineer undertakes a project for a client his primarv obligation is always to Why do the hydrogen ion (H+) and the hydroxide (OH') have so much impact on water chemistry? N M M i A my _\ 3W? y f I, ’1 ‘1 fl , fr - wagging, {fir/674%; j€§w¥2ff€ {My/fag if éjyzirflfi Cy/ f; [3/ 5:: ff {1 a“ /;,x';;5 {1/ « ' "2‘ " “i Problems (10 points each, show work) 10. A chromium (Cr) plated cup is filled with distill water and allowed to sit for a very long time with a water with a pH of 5.5. A great time later you come by and drink the water. I}, . A ,Mmmjijm .9 1”" M ,3 My WWW f,” :6 k 45* W ‘ yr / A“ 3 N C? l” ,) £3” f [:3 if I} ‘:;::373g§/"“ (f: v: ’ .12 A r m “a .r > W, w . A Mi» ":3 fl 3 A“ ~ MLM’fé/lfij f 1/, 52/»; i x » A» ---- ~ :3 WWW , r”? ,J. W 4?in M 56’?" W7 5}» Vii/’57}! / r r 2r w MM..- 4 g m i.. if M) A” y ,,M A (/14? ’ J x ll; 5:, t 1 1. You add 34 mg of NaCl to a 5 gallon bucket of distilled water. After awhile the salt completely disassociates to Na+ and Cl' . What is the molar concentration of the Cl' ion? a J ; (4;va f 43 “11/ “in: 5 N " w,“ i 13. Ratio of hydrogen sulfide (HS') to sulfuric acid (H28) to at a pH of 6. 14. A pipe flowing at a rate of 0.1 Ingd contains a Ca“? concentration of 14 mg/L. A wastewater discharge flowing into the pipe at 20 gpm contains 500 mg-Ca.++/L. What is the Ca++ concentration downstream of the mixing point? (Express results in mg-Ca++/L) “yew: :nxml:fl.wk’fl¢>&i‘dktwprKAA/flumacwww m _ 15. A sample of water contains 3 mg/L of Pei“. Express this concentration in meq/L. 16. How much CuSO4 ( a common 21] gaecide) must be added to a 1 acre pond with an average depth of 3 ft to achieve an instantaneous Cu++ concentration of 0.2 mg CUM/L. Express results in lbs. (Assume instantanepus mixing and dissolution to Cu H and $04") . t . ,V in {jg/y Table 2-4 Typical solubility-product constants Equilibrium equation Mgco3 : Mg“ + co;" Mg(0H)2 = Mg“ + 201-!“ caco3 :2 Ca“ + Cog- Ca(0H)2 = Ca“ + 20H- CaSO4 : Co“ + so:w Cutom, a Cu2+ + 20H- Zn(OH)z =1 ZnM + 20H“ Ni€OI-l), = Ni“ + 201-!” (31101113 :2 or3+ + 30H” Alton)3 = Al“ + 30H- morns a Few + 303“ F¢(0H)z =3 Fe“ + 20H” MIKOB); =1" Mn3+ + 30H' Mn(OH), :2 Mn“ + 20K" C33(P04)g 3C3”. "i" 21,04” Cal-IP04 =3 Ca” + HPOi“ CaFg 3 Ca“ + 2F” AgCl :2 Ag“ + Cl’ BaSO. # Ba“ + 803‘ K", at 25°C 4 x 10“ 9 X 10"-5 5 x 10'“ 8 x 10‘“ 2 x 10“ 2 x 10"“ 3 x 10*17 2 x 10*“ 6 X It?“ 1 x 10*” 6 x 10“38 5 X l0““’ 1 X 10’“ 8 x 10‘” lxlO‘"' 3 x to” 3 x 10*“ 3 x 10"” l x It)"0 Significance in environmental engineering Hardness removal, scaling Hardness rem0val. scaling Hardness removal, scaling Hardness removal Flue gas desulfurization Heavy metal removal Heavy metal removal Heavy metal removal Heavy metal removal Coagulation Coagulation, iron removal, corrosion Coagulation, iron removal. corrosion Manganese removal Manganese removal Phosphate removal Phosphate removal Fluoridation Chloride analysis Sulfate analysis Table 5-1 Typical ionization constants for weak acids at 25°C W K,‘ PKA Significance in environmental engineering M Acid Equilibrium equation Acetic CHHCOOH = H+ + CHBCOO’ Boric H3803 = H" + H2805 Carbonic C0, + H,O = H‘ e HCO; HCO; :1 H” + CUE HCN :: H‘ + CN- H28 :: w + HS" HS“ 2 H+ + S’-’ HOCl = H‘ + 0C]— Hydrocyanic Hydrosulfuric Hypochlorous Phenol Col-l50H -"—’ H‘ + CJ-IEO' Phosphoric HaPOJ =‘- H’ + HgPOJ H1PO; = H’ + HPOE’ HPO‘i‘ = H+ + P03“ CH3CH,C00H = w + CHaCH,COO' Propionic 1.8 x 10" 4.7 5.8 x 10"“tK.l 9-2 4.3 x 10"(K.l 6-4 4.7 x l0“'{K,l l0.3 7.2 x 10"" 9.1 9.: x [0"‘(Krl 7.0 1.3 x [0““(K2l 12.9 2.9 x it)“ 7.5 [.2 x term 93 7.5 x 10“‘(Kll 2.1 6.2 X l0‘“(K;l ,7.2 4.8 X IO'WKH} 12.3 1.3 x 10-5 4.9 Organic wastes Nitrogen analysis Many applications Toxicity Odors. corrosion Disinfection Tastes Analytical buffer, plant nutrient Organic wastes. anaerobic digestion - W Atomic weights of elements (“c = 12.0000 amu) Actinium Aluminum Americium Antimony Argon Arsenic Astatine Barium Berkelium Beryllium Bismuth Boron Bromine Cadmium Calcium Californium Carbon Cerium Cesium Chlorine Chromium Cobalt Copper Curium Dysprosium Einsteinium I Erbium Europium Fermium Fluorine Francium Gadolinium Gallium Germanium Gold Hafnium Hahnium Helium Holnium Hydrogen Indium Iodine Iridium Lutetium Magnesium Manganese Atomic Symbol number 89 13 95 51 18 33 85 56 97 4 83 S 35 48 20 98 6 58 55 17 24 27 29 96 66 99 68 63 100 9 87 64 3 1 32 79 72 105 2 67 l 49 53 77 26 36 104 57 103 82 3 71 12 25 Atomic weight [2271 26.9815 [243} 121.75 39.948 74.9216 [210] 137.34 [249} 9.0122 208.980 10.81 79.904 1 12.40 40.08 [2511 12.01 140.12 132.905 35.453 51.996 58.9332 153.54 [2471 162.50 {254] 167.26 151.96 [2531 18.9984 [223] 157.25 69.72 72.59 196.967 178.49 [260] 4.0026 164.930 1.0079 114.82 126.9045 192.22 55.847 83.80 [257] 138.91 [257] 207.2 6.941 174.97 24.305 54.9380 Mendelevium Mercury Molybdenum Neodymium Neon Neptunium Nickel Niobium Nitrogen Nobelium Osmium Oxygen Palladium Phosphorus Platinum Plutonium Polonium Potassium Praseodymium Promethium Protactinium Radium Radon Rhenium Rhodium Rubidlum Ruthenium Samarium Scandium Selenium Silicon Silver Sodium Strontium Sulfur Timtalum Technetium 'Ibllurium Terbium Thallium Thorium Thulimn Tin Titanium Tungsten Uranium Vanadium Xenon Ynerbium Yttrium Zinc Zirconium §§<§§<C€d§§§dglfiéfim Atomic number 101 80 42 60 10 93 28 41 7 102 76 8 46 15 78 94 84 19 59 61 91 88 86 75 45 37 44 62 21 34 14 47 ll 38 16 73 43 52 65 81 90 69 50 22 74 92 23 54 70 39 30 40 Atomic weight [256] 200.59 95.94 114.24 20.179 237.0482 58.7 92.906 14.0067 [254] 190.2 15.9994 106.4 30.9738 195.09 [242] [2101 39.096 140.9077 [1451 {23112310359 1226122613254 [222] 186.2 102.905 85.4678 101.07 150.35 44.956 78.96 28.086 107.868 22.9898 87.62 32.06 180.948 98.9062 127.60 158.9254 204.37 232.038 168.934 118.69 47.90 183.85 238.03 50.94 131.30 173.04 88.9059 65.38 I 9122 Note: A value given in brackets denotes the mass number of the longest-lived or best-known isotope. Common Conversions for the Environmental Engineer Primary unit _ Secondarv unit 3.785 liters per gallon 7.5 gallons per ‘ cubic foot 43,560 feet squared per acre L 454 grams J per Pounds (1b) 2.2 pounds (lb) per kilogram ' 2,200 pounds per Metric ton 1000 kilogram per Metric ton fl 1440 minutes per day 60 seconds per minute _I________.W per ‘7 ...
View Full Document

This note was uploaded on 05/20/2010 for the course EVEG 3110 taught by Professor Malone during the Spring '10 term at LSU.

Page1 / 7

Chemistry_exam_Spr_2006_solutions_v1 - Exam #1 Chemistry...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online