SMART CHEM 1022 Review
All questions are adopted from Prof. Leopolds Spring 2007 and 2006 exams
Atomic Properties
1. For which of the following would dipole-induced dipole be the strongest type of intermolecular
force between the two compounds?
a. methanol (CH30H), Cl2
b. water, KCl
c. methanol (CH30H), ethanol (CH3CH2OH)
d. K+, methane (CH4)
e. cyclopentane (C5H10), Cl2
Solutions
1. C6H12O6 is dissolved in 1.00L of H2O whose initial vapor pressure is 23.8 torr. After addition of the
sugar, the vapor pressure of the solution drops to 21.4 torr. Using this information, calculate
both the mole fraction of the solute and the mass, in grams, used.
2. Which of the following liquids would have the lowest boiling point?
a. NaCl (0.75 m in water)
b. NaN03 (0.25 m in water)
c. methanol (0.25 m in water)
d. pure water
e. the lowest boiling point cannot be determined
3. Assuming ideal behavior, what is the freezing point of a 0.70m solution of glucose in water?
(water has Kf=1.86 °C/m, Kb=0.51°C/m, 18.0 g/mol)
a. 1.30 ºC
b. 0.36 ºC
c. 0.00 ºC
d. -0.36 ºC
e. -1.30 ºC
Rate Laws
Initial Rate
Experiment
1
2
[𝐴]0 𝑀
4.00
4.00
[𝐵]0 𝑀
4.00
2.00
𝑚𝑜𝑙
𝐿∙𝑠𝑒𝑐
640.0
80.0
1.
An
experiment is done to
determine the rate law for
a
reaction which uses two
reactants, A and B. Determine the rate law from the following experimental data:
3
4
1.00
1.00
2.00
1.00
20.0
2.5
2. The reaction 2N205 (g) → 02 (g) + 4NO2 (g) is first order in N205. At a particular temperature,
the rate constant is 1.0 x 10-4 s-1. If initially the [N205] = 0.0040 M, what is the [N205] after
20,000 seconds.
a. 0.0041M
b. 0.0026M
c. 0.0015M
d. 0.00054M
e. 0.00020M
3. For a reaction in which A and B react to form C, what is the rate law for the reaction in which the
following initial raw data was obtained?
a.
b.
c.
d.
[A]0 (mol/L)
[B]0 (mol/L)
Initial Rate of Formation of C (mol/Ls)
0.2
0.4
2.00
0.2
0.8
4.00
0.2
1.6
8.00
0.4
0.4
8.00
0.8
0.4
32.00
rate = k [A]2[B]
rate = k [A][B]3
rate = k [A]2[B]2
rate = k [A]2
e. rate = k [A]2[B]3
Properties of solutions
1. 0.500 grams of a non electrolyte is dissolved in 25.0 mL of H2O which decreases the freezing
point by 0.180⁰C. Given that the Kf and Kb for H2O is -1.86 and 0.512
℃
𝑚
respectively, what is the
molar mass of the solute?
Equilibrium
1. If the equilibrium for the reaction 𝐶𝑙(𝑔)2 + 2𝑂(𝑔)2 ↔ 2𝐶𝑙𝑂(𝑔)2 is 2.9 × 10−21 , what is the
partial pressure of ClO2 from the reaction of 1.00 atm of O2 and equal amounts of Cl2?
2. Calculate the equilibrium constant for the following reaction. 2A ⇌ B + 2C
Initially the concentration of A was 5.5M, B was 2.0 M and no C was present. At equilibrium the
concentration of A was 2.5 M.
a. 6.3
b. 5.0
c. 4.6
d. 2.4
e. 1.0
Acid Base
1. If 0.050 L of 0.100M acetic acid, with a pKa of 4.76, is titrated with 0.015L of 0.100M NaOH, what
will the resultant pH be?
2. What is the pH of 0.90 M NH3 solution? Kb=1.8x10-5
a. 2.56
b. 4.56
c. 7.40
d. 9.10
e. 11.60
Thermodynamics
1. Under what conditions is a reaction non-spontaneous at all temperatures?
2. For the following reaction at equilibrium, which choice gives a change that will shift the
equilibrium to the left? ∆H°= 30kJ
2NOBr (g) ⇌ 2NO (g) + Br2 (g)
a.
b.
c.
d.
e.
increase the volume
remove Br2
remove NOBr
remove NO
two of these changes
3. Which of the following results in a decrease in the entropy of the system?
a. 02 (g), 300K → 02 (g), 400 K
b. H20 (l) → H20 (g)
c. 2N02 (g) → N204 (g)
d. NH3 (s) → NH3 (l)
e. 2H20 (g) → 2H2 (g) + 02 (g)
4. Given N2H4 (l) + 2H20 (l) ⇌ N2 (g) + 4H20 (g) ∆°H = -530kJ at 298K
Which of the following is true?
a. the reaction is spontaneous at high temperatures
b. the reaction is spontaneous at low temperatures
c. the reaction is spontaneous at all temperatures
d. the reaction is not spontaneous at any temperature
Electrochemistry
1. A galvanic cell uses a hydrogen electrode and lithium. Given that the standard reduction
potential of lithium is -3.0401 and that of hydrogen is zero, what is the chemical potential of the
battery if the initial concentration of ionic lithium is 5mM?
2. An electrochemical cell involves the following half-reactions. Under standard conditions, what
species are produced at each electrode?
Ag+(aq) + e- → Ag(s)
Cu2+(aq) + 2e- →Cu(s)
0.80V
0.34V
a.
b.
c.
d.
3.
Ag+ (aq) is produced at the cathode and Cu(s) at the anode
Ag+ (aq) is produced at the anode and Cu (s) at the cathode
Ag (s) is produced at the anode and Cu2+ (aq) at the cathode
Ag (s) is produced at the cathode and Cu 2+ (aq) at the anode
For the reaction Zn(s) + Cu2+(aq) ⇌ Cu(s) + Zn2+(aq) the cell voltage is 1.10 V under standard
conditions. What is the voltage if [Cu2+] =0.200M and [Zn2+]=0.060M?
a. 1.01 V
b. 1.12 V
c. 1.19 V
d. 1.26 V
e. 1.41 V