The Islamic University of Gaza
Chemistry Department
General Chemistry B.(CHEMB 1301)
Time: 1 hour
..............................‫ اسم المدرس‬.............................................. ‫الرقم الجامعي‬
20
......................................‫اسم الطالب‬
Q1- Choose the correct answer:
1- Which of the following can form intermolecular hydrogen bonds in the pure liquid?
1. CH4
2. CH3-O-CH3
3. CH3COOH 4. CH3NH2
a. 2, 4
b. 1, 3
c. 1, 2
d. 3, 4
2- Given the following liquids and their boiling points, which has the highest vapor pressure at its normal boiling
point?
a. ethanol bp = 78oC
b. methanol bp = 65oC
o
c. water bp = 100 C
d. The vapor pressures would all be the same.
3- Which of the following has the highest heat of vaporization?
a. H2Te
b. H2S
c. H2Se
d. H2O
4- Which of the following solutions should have the lowest freezing point?
a. 0.012 m Ce(NO3)4
b. 0.012 m ScCl3
c. 0.02 m NaCl
d. KNO3
5- The density of a 56.0% by weight aqueous solution of 1-propanol (CH3CH2CH2OH) is 0.8975 g/cm3. What is the
molality of the compound?(Atomic weights: C = 12.01, H = 1.008, O = 16.00).
a. 21.2
b. 13.5
c. 8.36
d. 17.2
6- The density of a 0.641 M solution of Pb(NO3)2 solution is 1.18 g/cm3? What is the molality of the solution?
(Atomic weights: Pb = 207.2, N = 14.01, O = 16.00).
a. 0.662
b. 0.0662
c. 0.0641
d. 0.545m
7- Which of the following aqueous solutions should have the highest osmotic pressure?
a. 0.02 M sucrose at 50oC
b. 0.012 M CaCl2 at 50oC
o
c. 0.008 M NaCl at 25 C
d. 0.012 M CaCl2 at 25oC
8- The following rate data were obtained for the given reaction. What is the rate-law expression for the reaction:
I- + OCl-
IO- + Cl-
Exp. [I-] [OCl-] Rate of formation of Cl- (M/sec)
1
0.10 0.050 3.05 x 10-4
2
0.20 0.050 6.10 x 10-4
3
0.30 0.100 1.83 x 10-3
a. rate = k[I-] [OCl-]2
c. rate = k[I-]
b. rate = k[I-] [OCl-]
d. rate = k[I-]2 [OCl-]
1
9- The half life of a first order reaction is 205 sec. What is the first order rate constant (sec-1)?
a. 3.38 x 10-3
b. 1.56 x 10-3
10- The units for a first-order rate constant are:
a. M/s
b. 1/M·s
c. 2.26 x 10-3
d. 3.03 x 10-3
c. 1/s
d. 1/M2·s
Q2- Answer All Questions:
1- How much energy (heat) is required to convert 52.0 g of ice at ─10.0oC to steam at 100oC?
Given: specific heat of ice:
2.09 J/g·oC ΔHfus = 6.02 kJ/mol
specific heat of water: 4.18 J/g·oC ΔHvap = 40.7 kJ/mol
specific heat of steam: 1.84 J/g·oC
a. 2570 kJ
b. 1,086 kJ
c. 157.8 kJ
d. 40.2 kJ
2- The vapor pressure of carbon tetrachloride (CCl4) at 65oC is 531 mm Hg. A solution of 20.0 g of a nonvolatile
solute in 154 g of CCl4 has a vapor pressure of 504 mm Hg at 65oC. What is the molecular weight of the
solute?(Atomic weights: C = 12.01, Cl = 35.45).
a. 415
b. 373
c. 399
d. 359
3- A solution of 1.14 g of a hydrocarbon dissolved in 50.0 g of CCl4 boils at 77.14oC. The normal boiling point of
CCl4 is 76.50oC and its Kb is 5.03 oC/molal. What is the molecular weight of the compound?
a. 179
b. 188
c. 158
d. 166
4- The rate constant of a second order reaction is 4.03 x 10-3 M-1 s-1. What concentration of reactant will remain
after 356 sec for an initial concentration of 0.300 M?
a. 0.210
b. 0.260
c. 0.175
d. 0.245
5- At 35oC and 70oC the first order rate constants of a reaction are 2.50 x 10-5 and 3.26 x 10-3 s-1 respectively. What
is the energy of activation (kJ/mole)?).
a. 117
b. 127
c. 122
2
d. 130