CEE 370 |
Spring 2001 |
March 15, 2001
Closed Book, one sheet of notes allowed
Please answer any 5 of the following 13 questions. Each is worth 20 points. Show all work. Be neat, and box-in your answer.
The balanced stoichiometric equation is:
The ThOD is then:
The balanced stoichiometric equation is:
The ThOD is then:
Hexane is a member of the Alkane family.
Oxalic Acid is a member of the Carboxylic Acid family.
Ethanol is a member of the Alcohol family.
Due to an excess of one or more reactants, the reaction rate is proportional to the concentration of only one of the reactants
Light of low wavelength (thus, high energy) strikes oxygen in the upper atmosphere to form ozone. This high energy light does not substantially penetrate into the lower atmosphere.
Partitioning occurs where a pollutant separates from the dissolved state to a state where it is associated with a particle or solid surface. The nature of this association may be either a direct link to the solid surface (adsorption) or dissolution into an organic layer attached to the surface.
Chemical Substance |
Conc. (mg/L) |
GFW |
Conc. (mM) |
Conc. (meq/L) |
Na+ |
31.2 |
22.9898 |
1.3571236 |
1.3571236 |
K+ |
1.5 |
39.0983 |
0.0383648 |
0.0383648 |
Ca+2 |
42.8 |
40.08 |
1.0678643 |
2.1357285 |
Mg+2 |
3.5 |
24.305 |
0.1440033 |
0.2880066 |
NO3- |
8.8 |
62.0049 |
0.1419243 |
0.1419243 |
SO4-2 |
14.6 |
96.0576 |
0.1519921 |
0.3039843 |
Cl- |
37.2 |
35.453 |
1.0492765 |
1.0492765 |
HCO3- |
59.3 |
61.0171 |
0.9718587 |
0.9718587 |
cations = |
3.81922356 |
anions = |
2.46704376 |
|
|
% diff. =
|
35.40% |
This tells us that there is a substantial error. Either the cations are over estimated, the anions are underestimated or there is a major anion that was omitted.
|
Chemical
Substance |
Conc. (mg/L) |
|
Na+ |
31.2 |
|
K+ |
1.5 |
|
Ca+2 |
42.8 |
|
Mg+2 |
3.5 |
|
NO3- |
8.8 |
|
SO4-2 |
14.6 |
|
Cl- |
37.2 |
|
HCO3- |
59.3 |
|
Sum = |
198.9 |
mg/L |
|
or |
Sum = |
139.6 |
mg/L |
with loss
of CO2 |
Chemical
Substance |
Conc. (mg/L) |
GFW |
Conc. (mM) |
Conc. (meq/L) |
z |
z^2 |
cz^2 (M) |
Na+ |
31.2 |
22.9898 |
1.3571236 |
1.3571236 |
1 |
1 |
0.001357 |
K+ |
1.5 |
39.0983 |
0.0383648 |
0.0383648 |
1 |
1 |
3.84E-05 |
Ca+2 |
42.8 |
40.08 |
1.0678643 |
2.1357285 |
2 |
4 |
0.004271 |
Mg+2 |
3.5 |
24.305 |
0.1440033 |
0.2880066 |
2 |
4 |
0.000576 |
NO3- |
8.8 |
62.0049 |
0.1419243 |
0.1419243 |
1 |
1 |
0.000142 |
SO4-2 |
14.6 |
96.0576 |
0.1519921 |
0.3039843 |
2 |
4 |
0.000608 |
Cl- |
37.2 |
35.453 |
1.0492765 |
1.0492765 |
1 |
1 |
0.001049 |
HCO3- |
59.3 |
61.0171 |
0.9718587 |
0.9718587 |
1 |
1 |
0.000972 |
|
|
|
|
|
|
0.5*Sum = |
0.004507 |
1. |
T |
A 1N
concentration is the same as 1 equivalent/L |
2. |
F |
A water
having 100 mg/L of hardness as CaCO3 may also be said to have 10
moles/L of hardness |
3. |
T |
The
activity coefficient usually goes down as ionic strength goes up. |
4. |
F |
A first
order reaction is almost always slower that a second order reaction |
5. |
T |
Catalysts
accelerate chemical reactions by lowering the activation energy |
6. |
F |
When Gibbs
Free Energy increases, the reaction will tend to go forward |
7. |
F |
Alkenes all
have triple bonds |
8. |
T |
Henry’s law
describes the relationship between partial pressure and dissolved
concentration |
9. |
T |
As the
organic content of a sediment increases, its ability to accumulate organic
contaminants by partitioning increases |
10. |
F |
TSS is
always greater than TDS |
Temperature |
Rate constant |
20°C |
3.6 M-1s-1 |
50°C |
56.2 M-1s-1 |
Best to use the Arrhenius Equation:
so then:
so:
HPO4-2 = PO4-3 + H+
Species:
Equations:
First, you must balance the REDOX equation to get the stoichiometry. This requires that the oxidation states for N and Mn be determined, and the electrons be balanced, then balance all non-H/O atoms, finally balance the O atoms with water as needed, and the H with the proton as needed.
now calculate:
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 |
|
Cerium |
Ce |
58 |
140.12 |
3,4 |
1.06 |
|
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 |
|
Osmium |
Os |
76 |
190.2 |
2,3,4,8 |
1.52 |
|
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 (&2) ACIDS |
|
Nitric acid |
HNO3 = H+ + NO3- |
-0 |
|
Hydronium ion |
H3O+ = H+ + H2O |
0 |
|
Bisulfate ion |
HSO4- = H+ +
SO4-2 |
2 |
|
Phosphoric acid |
H3PO4 = H+ + H2PO4- |
2.15 (&7.2,12.3) |
|
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 (&10.33) |
|
Hydrogen sulfide |
H2S = H+ + HS- |
7.02 (&13.9) |
|
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 |
|
Water |
H2O = H+ + OH- |
14.00 |
|