CEE 370 |
Fall 2006 |
October 16, 2006
Closed Book, one sheet of notes allowed
Please answer any 4 of the following 9 questions. Each is worth 25 points. Show all work. Be neat, and box-in your answer.
Chemical Substance |
Conc. (mg/L) |
Na+ |
12.5 |
K+ |
1.1 |
Ca+2 |
39.3 |
Mg+2 |
3.5 |
NO3- |
8.8 |
SO4-2 |
12.4 |
Cl- |
33.9 |
HCO3- |
112.3 |
Location |
Q (cfs) |
Chloride (mg/L) |
1 (main inflow) |
15 |
2 |
2 (side inflow) |
3 |
6 |
3 (side outflow) |
??? |
??? |
4 (main outflow) |
17 |
??? |
Time (min) |
Concentration (µM) |
0 |
100 |
50 |
22 |
100 |
5 |
1. |
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The Arrhenius equation allows one to adjust rate constants from one temperature to another |
2. |
|
A triprotic acid has three times the strength as a monoprotic acid |
3. |
|
A conjugate base is what forms when an acid losses a proton
|
4. |
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When an organic compound name ends in “ol”, it usually means the compound is an alcohol |
5. |
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Catalysts accelerate chemical reactions by lowering the activation energy
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6. |
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When Gibbs Free Energy increases, the reaction will tend to go forward
|
7. |
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Alkynes all have triple bonds
|
8. |
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Henry’s law describes the relationship between partial pressure and dissolved concentration |
9. |
|
BTEX is a new type of dog food
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10. |
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Changes in ionic strength can cause shifts in chemical equilibria
|
11 |
|
An element of high electronegativity will share its bonding electrons equally with an element of low electronegativity |
12 |
|
Biochemical oxygen demand (BOD) differs from theoretical oxygen demand (ThOD) in that BOD only refers to oxygen demand from pharmaceuticals |
HCO3- = CO3-2 + H+
Selected Chemical Constants
Element |
Symbol |
Atomic # |
Atomic Wt. |
Valence |
Electronegativity |
|
Aluminum |
Al |
13 |
26.98 |
3 |
1.47 |
|
Boron |
B |
5 |
10.81 |
3 |
2.01 |
|
Calcium |
Ca |
20 |
40.08 |
2 |
1.04 |
|
Carbon |
C |
6 |
12.01 |
2,4 |
2.50 |
|
Chlorine |
Cl |
17 |
35.453 |
1,3,5,7 |
2.83 |
|
Chromium |
Cr |
24 |
52.00 |
many |
1.56 |
|
Helium |
He |
2 |
4.00 |
0 |
|
|
Holmiuum |
Ho |
67 |
164.93 |
3 |
1.10 |
|
Hydrogen |
H |
1 |
1.01 |
1 |
2.20 |
|
Magnesium |
Mg |
12 |
24.31 |
2 |
1.23 |
|
Manganese |
Mn |
25 |
54.94 |
2,3,4,6,7 |
1.60 |
|
Nitrogen |
N |
7 |
14.01 |
many |
3.07 |
|
Oxygen |
O |
8 |
16.00 |
2 |
3.50 |
|
Potassium |
K |
19 |
39.10 |
1 |
0.91 |
|
Sodium |
Na |
11 |
22.99 |
1 |
1.01 |
|
Sulfur |
S |
16 |
32.06 |
2,4,6 |
2.44 |
|
Selected Acidity Constants (Aqueous Solution, 25°C, I = 0)
NAME |
FORMULA |
pKa |
|
Hydrochloric acid |
HCl = H+ + Cl- |
-3 |
|
Sulfuric acid |
H2SO4= H+ + HSO4- |
-3 |
|
Nitric acid |
HNO3 = H+ + NO3- |
-0 |
|
Bisulfate ion |
HSO4- = H+ + SO4-2 |
2 |
|
Phosphoric acid |
H3PO4 = H+ + H2PO4- |
2.15 |
|
Hydrofluoric acid |
HF = H+ + F- |
3.2 |
|
Nitrous acid |
HNO2 = H+ + NO2- |
4.5 |
|
Acetic acid |
CH3COOH = H+ + CH3COO- |
4.75 |
|
Propionic acid |
C2H5COOH = H+ + C2H5COO- |
4.87 |
|
Carbonic acid |
H2CO3 = H+ + HCO3- |
6.35 |
|
Hydrogen sulfide |
H2S = H+ + HS- |
7.02 |
|
Dihydrogen phosphate |
H2PO4- = H+ + HPO4-2 |
7.2 |
|
Hypochlorous acid |
HOCl = H+ + OCl- |
7.5 |
|
Ammonium ion |
NH4+ = H+ + NH3 |
9.24 |
|
Hydrocyanic acid |
HCN = H+ + CN- |
9.3 |
|
Phenol |
C6H5OH = H+ + C6H5O- |
9.9 |
|
Bicarbonate ion |
HCO3- = H+ + CO3-2 |
10.33 |
|
Monohydrogen phosphate |
HPO4-2 = H+ + PO4-3 |
12.3 |
|
Bisulfide ion |
HS- = H+ + S-2 |
13.9 |
|