Department of Chemistry
and Physics
Exam 4
|
Department of Chemistry and Physics |
| CHEM2004 |
Exam 4
|
CHEM2004 Name_________________________
Exam 4 Fall 2009
1. CH3O- (methoxide) and NH2- (amide) are stronger bases than OH-. Why can’t methoxide and amide exist in water? Show reactions for full credit. (8 points)
2. Describe how sulfuric acid is prepared industrially starting from sulfide ores. (8 points)
Bonus: (2 points) what percentage of sulfuric acid is concentrated sulfuric acid? _______
3. Describe how phosphoric acid is prepared from elemental phosphorus. (6 points)
Bonus: (2 points) what molarity is concentrated phosphoric acid? _______
4. Predict the product(s) for the following reactions: Label the acidic oxide, basic oxide and balance the equation. (16 points)
P4O10 + FeO g
l2O5 + H2O g
MnO + H + g
CaO + SiO2 g
5. Determine the C.N.(+), C.N.(-) and the lattice for: (12 points)
|
|
lattice |
C.N.(+) |
C.N.(-) |
properties
|
|
CuO |
|
|
|
|
|
CdCl2 |
|
|
|
|
|
V2O5 |
|
|
|
|
V 68; Cu 87; Cd 109; O 126; Cl 167 pm
6. Describe the effect on pH of each of the following when placed in water: (8 points)
a) CO
b) Fe2O3 (Fe is a moderately acidic cation)
c) CO2
d) Na2O (Na is a nonacidic cation)
7. Match the oxide that bests fits with the property listed below: Some are used more than once. (20 points)
| _____ syngas | a) CO |
| _____ food preservative | b) CO2 |
| _____ forms sulfuric acid in H2O | c) SO2 |
| _____ desiccant | d) SO3 |
| _____ fire extinguisher | e) N2O |
| _____ dry ice | f) NO |
| _____ water gas | g) NO2 |
| _____ anesthetic | h) P4O10 |
| _____ Fischer-Tropsch process | |
| _____ photosynthesis |
8. Why should you be careful when using P4O10 as a drying agent for organic solvents? (4 points)
9. List the environmental problems associated with NOx’s. (6 points)
10. List the three nonmetal oxides that have neutral aqueous solutions. (3 points)
11. Circle the nonmetal oxides that are free radicals. (4 points)
CO2 ClO2 NO N2O CO SO2
12. List the five naturally occurring Greenhouse gases. (5 points)
|
r+/ r- |
Lattice type |
C.N. (+) |
C.N. (-) |
|
a) MX |
|
|
|
|
0.225 – 0.414 |
Wurtzite |
4 |
4 |
|
|
Zinc blende |
4 |
4 |
|
0.414 – 0.732 |
Rock salt |
6 |
6 |
|
0.732 – 1.000 |
CsCl |
8 |
8 |
|
b) MX2 |
|
|
|
|
0.225 – 0.414 |
Beta-quartz |
4 |
2 |
|
0.414 – 0.732 |
Rutile |
6 |
3 |
|
0.732 – 1.000 |
Fluorite |
8 |
4 |
|
c) M2X3 |
|
|
|
|
0.414 – 0.732 |
corundum |
6 |
4 |
|
d) other |
|
|
|
|
Never favored |
Ion pair |
1 |
1 |
|
0.000 – 0.155 |
|
2 |
|
|
0.155 – 0.225 |
|
3 |
|
|
0.225 – 0.414 |
|
4 |
|
|
0.414 – 0.732 |
|
6 |
|
|
0.732 – 1.000 |
|
8 |
|
|
1.000 |
|
12 |
|