AP Chemistry Fall Semester Practice Exam 4
MULTIPLE CHOICE PORTION: Write the letter for the correct answer to the following questions
on the provided answer sheet. Each multiple choice question is worth 2 points.
1.
Which of the following represents the ground state electron configuration for the Mn+3 ion?
a. 1s22s22p63s23p63d4
d. 1s22s22p63s23p64s23d8
b. 1s22s22p63s23p64s23d5
e. 1s22s22p63s23p64s13d3
2 2
6 2
6 2
2
c. 1s 2s 2p 3s 3p 4s 3d
2.
Consider the following molecules: CCl4, CO2, PCl3, PCl5, SF6
Which of the following does not describe any of the molecules listed above?
a. linear
d. tetrahedral
b. octahedral
e. trigonal pyramidal
c. square planar
3.
Which of the following molecules has the shortest bond length?
a. N2
b. O2
c. Cl2
d. Br2
e. I2
4.
A student wishes to prepare 2.00 liters of a 0.100 M KIO3 solution. The proper procedure is to
weigh out:
a. 42.8 g of KIO3 and add 2.00 kg of water.
b. 42.8 g of KIO3 and add water until the final homogeneous solution has a volume of 2.00 L.
c. 21.4 g of KIO3 and add water until the final homogeneous solution has a volume of 2.00 L.
d. 42.8 g of KIO3 and add 2.00 L of water.
e. 21.4 g of KIO3 and add 2.00 L of water.
5.
Which of the following must be true for a reaction that proceeds spontaneously from initial
standard state conditions?
a. ΔG° > 0 and K > 1
d. ΔG° < 0 and K < 1
b. ΔG° > 0 and K < 1
e. ΔG° = 0 and K = 1
c. ΔG° < 0 and K > 1
6.
Which of the following has a zero dipole moment?
a. HCN
b. NH3
c. SO2
7.
d. NO2
e. PF5
Consider the following information:
1. Difference in temperature between freezing point of solvent and freezing point of solution.
2. Molal freezing point depression constant, Kf, for solvent.
In addition to the information above, which of the following gives the minimum data required to
determine the molecular mass of a nonionic substance by the freezing point depression
technique?
a. No further information is necessary.
d. Mass of solute and volume of solvent.
b. Mass of solute.
e. Mass of solute, mass of solvent, and
c. Mass of solute and mass of solvent.
vapor pressure of solvent.
8.
Consider the following reaction:
N2 (g) + 3 H2 (g) → 2 NH3 (g)
The reaction indicated above is thermodynamically spontaneous at 298K, but becomes
nonspontaneous at higher temperatures. Which of the following is true at 298K?
a. ΔG, ΔH, and ΔS are all positive.
b. ΔG, ΔH, and ΔS are all negative.
c. ΔG and ΔH are negative, but ΔS is positive.
d. ΔG and ΔS are negative, but ΔH is positive.
e. ΔG and ΔH are positive, but ΔS is negative.
9.
For which of the following molecules are resonance structures necessary to describe the bonding
satisfactorily?
a. H2S
b. SO2
c. CO2
d. OF2
e. PF3
10.
Pi bonding occurs in each of the following species EXCEPT:
a. CO2
b. C2H4
c. CN 1
−
11.
d. C6H6
e. CH4
What is the mole fraction of ethanol, C2H5OH, in an aqueous solution in which the ethanol
concentration is 4.6 m?
a. 0.0046
b. 0.076
c. 0.083
d. 0.20
e. 0.72
Questions 12-14 refer to atoms of the following elements.
a. lithium
b. carbon
c. nitrogen
d. oxygen
e. fluorine
12.
In the ground state, have only 1 electron in each of the three p orbitals.
13.
Have the smallest atomic radius.
14.
Have the smallest value for first ionization energy.
15.
The hybridization of the carbon atoms in C2H6 can be described as:
a. sp
b. sp2
c. sp3
d. dsp3
16.
Of the following organic compounds, which is the LEAST soluble in water at 298K?
a. CH3OH, methanol
d. C6H12O6, glucose
b. CH3CH2CH2OH, 1-propanol
e. CH3COOH, ethanoic acid
c. C6H14, hexane
17.
How many electrons can be accommodated in all the atomic orbitals that correspond to the
principal quantum number 4?
a. 2
b. 8
c. 18
d. 32
e. 40
e. d2sp3
18.
If ΔG for a certain reaction has a negative value at 298K, which of the following must be true?
I. The reaction is exothermic.
II. The reaction occurs spontaneously at 298K.
III. The rate of the reaction is fast at 298K.
a. I only
d. II and III only
b. II only
e. I, II, and III
c. I and II only
19.
A linear molecule can have the general formulas AA, AB, or AB2. Given a molecule with the
general formula AB2, which of the following would be the most useful in determining whether
the molecule was bent or linear?
a. Ionization energies
d. Electronegativities
b. Electron affinities
e. Bond energies
c. Dipole moments
20.
How many moles of solid calcium nitrate should be added to 450. mL of 0.35 M aluminum
nitrate to increase the concentration of the nitrate ion to 1.7 M? (Assume that the volume of the
solution remains constant.)
a. 0.07 mole
b. 0.14 mole
c. 0.29 mole
d. 0.45 mole
e. 0.77 mole
21.
The enthalpy change for the reaction, A → X is ΔHrxn. This reaction can be broken down into a
series of steps as shown in the diagram:
ΔH2
B
C
ΔH1
ΔH3
A
X
ΔHrxn
A relationship that must exist among the various enthalpy changes is:
a. ΔHrxn − ΔH1 − ΔH2 − ΔH3 = 0
b. ΔHrxn + ΔH1 + ΔH2 + ΔH3 = 0
c. ΔH3 − (ΔH1 + ΔH2) = ΔHrxn
d. ΔH2 − (ΔH3 + ΔH1) = ΔHrxn
e. ΔHrxn + ΔH2 = ΔH1 + ΔH3
22.
The valence electron configuration of element A is 3s23p1 and that of element B is 3s23p4. What
is the probable empirical formula for a compound of the two elements?
a. A2B
b. AB2
c. A3B2
d. A2B3
e. AB
23.
What is the molality of a 10.% C6H2O solution?
a. 0.012 m
b. 0.12 m
c. 1.2 m
d. 12 m
24.
A certain organic compound has a vapor pressure of 132 mm Hg at 54°C. To determine the
vapor pressure of 2.00 moles of the compound at 37°C, taking the heat of vaporization for the
compound to be 4.33 x 104 J/mol, you would use:
a. the Arrhenius equation
d. the ideal gas law
b. the Clausius-Clapeyron equation
e. Raoult's law
c. the combined gas laws
25.
Consider the following information:
Species
F⎯F
H⎯H
H⎯F
Calculate the value of ΔH for the following reaction:
H2 (g) + F2 (g) → 2 HF (g)
a. −406 kcal/mol
b. −320 kcal/mol
c. −271 kcal/mol
26.
Bond Energy (kcal/mole)
33
103
135
d. −134 kcal/mol
e. −1.00 kcal/mol
A molecule exhibits d2sp3 hybridization in its bonding structure. The most probable geometric
shape of this molecule is:
a. triangular bipyramidal
d. linear
b. T-shaped
e. square planar
c. octahedral
Questions 27-31 refer to the following entropy changes.
a. The change in entropy will be positive.
b. The change in entropy will be zero.
c. The change in entropy will be negative.
d. The change in entropy will be cannot be determined from the information given.
27.
Predict the change in entropy.
Cl2 (g) → 2 Cl (g)
28.
Predict the change in entropy.
H2 (g) at 5.0 atm → H2 (g) at 1.0 atm
29.
Predict the change in entropy.
Sublimation of solid CO2.
30.
Predict the change in entropy.
2 H2 (g) + O2 (g) → 2 H2O (g)
31.
Predict the change in entropy.
PCl5 (g) ↔ PCl3 (g)
32.
Calculate the volume of a 36.45% solution of hydrochloric acid (density 1.50 g/ml) required to
prepare 9.0 L of a 5.0 M solution.
a. 0.5 L
b. 1.0 L
c. 2.0 L
d. 2.5 L
e. 3.0 L
+ Cl2 (g)
33.
For the isoelectronic series, S 2, Cl 1, Ar, K+1, and Sc+3, which species requires the least energy to
remove an outer electron?
a. S 2
b. Cl 1
c. Ar
d. K+1
e. Sc+3
−
−
−
−
Questions 34-36 refer to the following phase diagram that is NOT drawn to scale.
Pressure (atm)
73.0
•
5.1
•
0.5
−78
−57
31
Temperature (°C)
a.
b.
c.
d.
e.
−78°C
−57°C, 5.1 atm
31°C, 73 atm
31°C
None of the above.
34.
What is the normal boiling point of the substance?
35.
Which point represents the critical point?
36.
Which point represents the triple point?
37.
Molecules that have trigonal planar configurations include which of the following:
I. BCl3
II. CHCl3
III. NCl3
a. I only
b. III only
c. I and II only
38.
d. II and III only
e. I, II, and III
Which of the following molecules is paramagnetic?
a. C2
b. N2
c. O2
d. F2
39.
What is the bond order of a molecule of nitrogen?
a. 3
b. 2
c. 1
d. 0
40.
Sterling silver, which contains 93% silver and 7% copper is a(n) ____________ alloy.
a. interstitial
b. substitutional
c. p-type
d. n-type
41.
Consider the following data:
Species
NO2 (g)
H2O (ℓ)
HNO3 (aq)
NO (g)
Calculate the value of ΔH° for the following reaction:
3 NO2 (g) + H2O (ℓ) → 2 HNO3 (aq) + NO (g)
a. −140. kJ
42.
b. 184 kJ
c. 140. kJ
ΔHf° (kJ/mole)
34
−286
−207
90.
d. −184 kJ
Types of hybridization exhibited by the C atoms in acetylene, C2H2, include which of the
following?
I. sp
II. sp2
III. sp3
a. I only
b. II only
c. III only
d. I and II only
e. I and III only
AP Chemistry Fall Semester Exam 2004
Name_______________________________
ESSAY PORTION: Write your answer on the provided answer sheet. This section is worth 16 points.
1.
For each of the following, use appropriate chemical principles to explain the observation.
a. When table salt (NaCl) and sugar (C12H22O11) are dissolved in water, it is observed that both
solutions have higher boiling points than pure water.
b. When table salt (NaCl) and sugar (C12H22O11) are dissolved in water, it is observed that the
boiling point of 0.10 M NaCl (aq) is higher than that of 0.10 M C12H22O11 (aq).
c. Water droplets form on the outside of a beaker containing an ice bath.
2.
Use the principles of atomic structure and/or chemical bonding to explain each of the following.
In each part, your answer must include references to both substances.
a. The second ionization energy of K is greater than the second ionization energy of Ca.
b. The carbon-to-carbon bond energy in C2H4 is greater than it is in C2H6.
c. The boiling point of Cl2 is lower than the boiling point of Br2.
3.
Consider the following reaction:
C (s) + CO2 (g) ↔ 2 CO (g)
Carbon (graphite), carbon dioxide, and carbon monoxide form an equilibrium mixture, as
represented by the equation above.
a. Predict the sign for the change in entropy, ΔS, for the reaction. Justify your prediction.
b. In the table below are data that show the percent of CO in the equilibrium mixture at two
different temperatures. Predict the sign for the change in enthalpy, ΔH, for the reaction. Justify
your prediction.
Temperature
% CO
60
700°C
94
850°C
AP Chemistry Fall Semester Exam 2004
ESSAY ANSWER SHEET:
1.
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b.
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Name_______________________________
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AP Chemistry Fall Semester Exam 2004
MULTIPLE CHOICE ANSWER SHEET:
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