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Title:
Practice Test 1
Started:
February 18, 2008 10:36 PM
Submitted:
February 18, 2008 11:31 PM
Time spent:
00:55:06
Total score: 16/20 = 80%
1.
Total score adjusted by 0.0
Maximum possible score: 20
IMF in solution 50
What is the strongest form of intermolecular force between solute and solvent in a solution of
C2H6(g) in benzene, C6H6(l)?
Student
Value
Response
Correct Answer Feedback
1. ion-dipole 0%
2. dipoledipole
0%
3. hydrogen 0%
bonding
4. dipoleinduced
dipole
0%
5. dispersion 100%
Score:
2.
1/1
Relative Solubility 22
Which of the following is more soluble in water, methanol or CBr2H2(l). Don't try to type the
subscripts, just use letters and numbers.
Student Response
1. CH3OH
Score:
3.
Value
Correct Answer
0%
Equals methanol (100%)
0/1
Chapter 8 Molality 7
Determine the molality of a solution prepared by dissolving 9.78 g of cycloheptane in 71.3 g of
benzene.
Student Response
Answer .140
Value
Correct Answer
0%
1.40
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Score:
4.
Page 2 of 8
0/1
Chapter 8 PC to Molar 1
A 4.20 mass % aqueous solution of sodium chloride has a density of 1.00 g/mL. Calculate the
molarity of the solution.
Student Response
Score:
5.
Correct Answer
100%
Answer .7186
Value
0.72
1/1
Ionic Dissociation 1
Describe sodium permanganate (NaMnO4) as a strong electrolyte, weak electrolyte,or nonelectrolyte.
Student Response
Score:
6.
Correct Answer
100%
1. strong
Value
Equals strong electrolyte (100%)
Equals strong (100%)
1/1
General Properties Comparison 3
Consider the solutions, 0.04 m urea [(NH2)2C=O)], 0.04 m AgNO3 and 0.04 m CaCl2. Which has
(i) the highest osmotic pressure, (ii) the highest vapor pressure, (iii) the highest boiling point?
Student
Value Correct Answer Feedback
Response
1. (a) 0.04
m CaCl2
0%
(b) 0.04
m CaCl2
(c) 0.04
m CaCl2
2. (a) 0.04
m CaCl2
100%
(b) 0.04
m urea
(c) 0.04
m CaCl2
3. (a) 0.04
m urea
0%
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(b) 0.04
m CaCl2
(c) 0.04
m urea
4. (a) 0.04
m CaCl2
100%
(b) 0.04
m urea
(c) 0.04
m urea
5. all will be 0%
the same
Score:
7.
0/1
Chapter 8 VP 4
Calculate the vapor pressure (in torr) at 310 K in a solution prepared by dissolving 18.2 g of the
non-volatile non-electrolye sucrose in 123 g of water. The vapor pressure of water at 310 K is
47.08 torr.
Student Response
Score:
8.
Correct Answer
100%
Answer 46.716
Value
46.72
1/1
Chapter 8 MM fp 9
When 1.58 g of an unknown non-electrolyte is dissolved in 50.0 g of acetone, the freezing point
decreased to -94.07 degrees C from -93.4 degrees C. If the Kfp of the solvent is 2.4 K/m,
calculate the molar mass of the unknown solute.
Student Response
Score:
9.
Correct Answer
100%
Answer 113.194
Value
113
1/1
Calculate k from Rate Law 34
Given the data below for the reaction, 2 A + 2 B + 4 C => D + E + 3 F, the reaction is [second]
order in A, [first] order in B, [first] order in C and [fourth] order overall. USE WORDS TO FILL IN
THE BLANKS NOT NUMBERS (i.e., zero, first, second etc) !!!!! :
Experiment
Initial conc of A,
mol/L
Initial conc of B,
mol/L
Initial conc of C,
mol/L
Initial rate,
mol/L.s
1
0.1
0.2
0.4
2 x 10-3
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2
0.2
0.2
0.4
8 x 10-3
3
0.3
0.4
0.4
3.6 x 10-2
4
0.4
0.6
0.2
4.8 x 10-2
Calculate the value of k to 3 significant figures.
Student Response
Score:
Correct Answer
0%
1. 2.5
Value
Equals 2.50 (100%)
0/1
10. Determine Rate Law 41
Given the data below for the reaction, 2 A + 2 B + 4 C => D + E + 3 F, the reaction is 1.----order in A, 2.----- order in B, 3.----- order in C and 4.----- order overall. USE WORDS TO FILL IN
THE BLANKS NOT NUMBERS (i.e., zero, first, second etc) !!!!! :
Experiment
Initial conc of A,
mol/L
Initial conc of B,
mol/L
Initial conc of C,
mol/L
Initial rate,
mol/L.s
1
0.1
0.2
0.4
2 x 10-3
2
0.2
0.2
0.4
2 x 10-3
3
0.3
0.4
0.4
4 x 10-3
4
0.4
0.6
0.2
1.5 x 10-3
Student Response
Value
Correct Answer
1. zero
25%
Equals zero (25%)
2. first
25%
Equals (25%)
3. first second
25%
Equals second (25%)
4. third
25%
Equals third (25%)
Score:
1/1
11. Arrhenius k 1 set of conditions 1
A first order reaction has an activation energy of 56.2 kJ/mol and a frequency factor (Arrhenius
constant) of 4.35 x 1013 sec -1. Calculate the rate constant at 16 oC.
Student Response
Answer 3025.27
Score:
Value
Correct Answer
100%
3,023
1/1
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12. IRL 1 c 2
A reaction has a rate constant of 0.0836 sec-1, how much of the compound (in mol/L) is left
after 4.44 sec, if there was 0.146 mol/L at the start? (give answer to 3 sig figs using E
notation)?
Student Response
Score:
Correct Answer
100%
Answer .1007
Value
0.101
1/1
13. IRL 1 t 7
A reaction has a rate constant of 0.708 sec-1, how long will it take (in seconds) until 0.186
mol/L of the compound is left, if there was 0.562 mol/L at the start? (give answer to 3 sig figs
using E notation)?
Student Response
Score:
Correct Answer
100%
Answer 1.56
Value
1.562
1/1
14. Mechanism and Rate Law 9
The proposed mechanism for a reaction is
NO + O3 => NO3 + O
Slow
NO3 + O => NO2 + O2
Fast
Which of the following would be a rate law for the reaction?
Student
Value Correct Answer Feedback
Response
1. rate = k 100%
[NO][O3]
2. rate = k
[O3]
0%
3. rate = k
[NO]
0%
4. rate = k 0%
[O][NO3]
5. rate = k
[NO2]
0%
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[O2]
Score:
1/1
15. Mechanism Molecularity 8
The proposed mechanism for a reaction is
1.Cl2 + H2S => HCl + Cl+ + HS- Slow
2. Cl+ + HS- => HCl + S
Fast
What is the molecularity of step 2?
Student
Response
Value
Correct
Answer
Feedback
1. unimolecular 0%
2. bimolecular
100%
3. trimolecular 0%
4. impossible
0%
to tell
without
knowing
which is the
slow step
Score:
1/1
16. Known Rate Law Change Conc 56
For the reaction, A(g) + B(g) => AB(g), the rate is 0.394 mol/L.s when the initial concentrations
of both A and B are 2.00 mol/L. If the reaction is first order in A and second order in B, what is
the rate when the initial concentration of A = 4.76 mol/L and that of B = 1.36 mol/L (give
answers in E notation to 3 significant figures)
Student Response
Answer 4.34E-1
Score:
Value
Correct Answer
100%
0.43
1/1
17. Chapter 5 IMF 27
Which type of intermolecular force ("interparticle force") is the most important in BCl3(l)?
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Student
Value
Response
Correct Answer Feedback
100%
1. London
Dispersion
2. Dipoledipole
forces
This is a non-polar molecule.
0%
3. Ion-dipole 0%
forces
4. Hydrogen 0%
bonds
5. Ionic
bonds
Score:
0%
1/1
18. Chapter 5 IMF 58
Which type of intermolecular force ("interparticle force") is the most important in
SO2(l)?
Student
Value
Response
Correct Answer Feedback
1. London
0%
Dispersion
2. Dipoledipole
forces
100%
This is a polar molecule.
3. Ion-dipole 0%
forces
4. Hydrogen 0%
bonds
5. Ionic
bonds
Score:
0%
1/1
19. Chapter 5 Phys Props 19
Which of the following substances would be expected to have the lowest heat of vaporization?
Student
Value Correct Answer Feedback
Response
1. methane 100%
For similar substances, lightest ones have the
lowest heat of vaporization
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2. CF4
0%
3. CCl4
0%
4. CBr4
0%
5. CI4
0%
Score:
1/1
20. Phase Change enthalpies 2
What is the heat change in J associated with 20.3 g of liquid water at 5.00 C changing to solid
water at -5.00 C?
c(H2 O) (liq) = 4.184 J/(g.K)
c(H2O) (s) = 2.09 J/ (g.K)
Hfus(H2 O) = 6.02 kJ/mol
Enter your answer in scientific format with TWO DECIMAL PLACES (that is, 3 significant figures
total): 1.23X104 =1.23E4. Do not include units. You will not get credit for the question if
you do not use the correct format!!!
Student Response
Answer -7.42E3
Score:
Value
Correct Answer
100%
-7.42E3 (-7.42 103)
1/1
Done
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