AAMC MCAT test 7

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MCAT
Practice Test 7


Physical Sciences
Time: 100 minutes
Questions: 1-77
Most questions in the Physical Sciences test are organized into groups, each containing a descriptive passage.
After studying the passage, select the one best answer to each question in the group. Some questions are not
based on a descriptive passage and are also independent of each other. If you are not certain of an answer,
eliminate the alternatives that you know to be incorrect and then select an answer from the remaining
alternatives. Indicate your selected answer by marking the corresponding answer on your answer sheet. A

periodic table is provided for your use. You may consult it whenever you wish.

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for the MCAT hold the copyrights to the content of this Practice Test. Therefore, there can be no sharing or
reproduction of materials from the Practice Test in any form (electronic, voice, or other means). If there are
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Periodic Table of the Elements

1

H

2

He
4.0
10

1.0
3

4

Li

Be

B

C

N

O

F

Ne

6.9

9.0

10.8

12.0

14.0

16.0

19.0

20.2

5

6

7

8

9

11

12

13

14

15

16

17

18

Na

Mg

Al

Si

P

S

Cl

Ar

23.0

24.3

27.0

28.1

31.0

32.1

35.5

39.9

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

K

Ca

Sc

Ti

V

Cr

Mn

Fe

Co

Ni

Cu

Zn

Ga

Ge

As

Se

Br

Kr

39.1
37

40.1
38

45.0
39

47.9
40

50.9
41

52.0
42

54.9
43

55.8

44

58.9
45

58.7
46

63.5
47

65.4
48

69.7
49

72.6
50

74.9
51

79.0
52

79.9
53

83.8

54

Rb

Sr

Y

Zr

Nb

Mo

Tc

Ru

Rh

Pd

Ag

Cd

In

Sn

Sb

Te

I

Xe

85.5
55

87.6
56

88.9
57

91.2
72

92.9
73

95.9
74

(98)
75

101.1

76

102.9
77

106.4
78

107.9
79

112.4
80

114.8
81

118.7
82

121.8
83

127.6
84

126.9
85

131.3

86

Cs

Ba

La*

Hf

Ta

W

Re

Os

Ir

Pt

Au

Hg

Tl

Pb

Bi

Po

At

Rn

132.9
87

137.3
88

138.9
89

178.5
104

180.9
105

183.9
106

186.2
107

190.2

108

192.2
109

195.1

197.0

200.6

204.4

207.2

209.0

(209)

(210)

(222)

Fr

Ra

Ac†

Unq†

Unp

Unh

Uns Uno Une

(223)

(226)

(227)

(261)

(262)
58

(263)
59

(262)
60

(265)
61

(267)
62

63

64

65

66

67

68

69

70

71

Ce

Pr

Nd

Pm

Sm

Eu

Gd

Tb

Dy

Ho

Er

Tm

Yb

Lu

140.1
90

140.9
91

144.2
92

(145)
93

150.4
94

152.0
95

157.3
96

158.9
97

162.5
98

164.9
99

167.3
100

168.9
101

173.0
102

175.0
103

Pa

U

Np

Pu

Am

Cm

Bk

Cf

Es

Fm

Md

No

Lr

232.0

(231)

238.0

(237)

(244)

(243)

(247)

(247)

(251)

(252)

(257)

(258)

(259)

(260)

*

† Th


Passage I
Thousands of tons of hydrazine (N2H4) are
produced each year for commercial uses, including

the production of agricultural chemicals. At room
temperature, hydrazine is a volatile liquid that exists
in hydrogen-bonded networks similar to those found
in liquid water. Hydrazine may be prepared by the
Raschig process, the reaction of ammonia with
sodium hypochlorite, as shown in Equation 1.
2NH3(g) + NaOCl(aq) → N2H4(aq) + NaCl(aq) +
H2O(ℓ)

Like ammonia, hydrazine is a base in aqueous
solution. Figure 1 shows the equilibria reactions of
ammonia and hydrazine in aqueous solution.
NH3(aq) + H2O(ℓ)
NH4+(aq) + OH-(aq)
Keq = 1.8 × 10-5
N2H4(aq) + H2O(ℓ)
N2H5+ + OH-(aq)
Keq = 8.5 × 10-7
N2H5+ + H2O
N2H62+ + OH-(aq)
Keq = 8.9 × 10-16
Figure 1 Equilibria (Keq = equilibrium constant)

Equation 1
Hydrazine usually is shipped as the hydrate (N2H4 ·
H2O) because it is easier to handle and can be easily
dehydrated to form the anhydrous compound.
Hydrazine and its chemical derivatives are good
rocket propellants. For example, hydrazine reacts
with dinitrogen tetroxide (N2O4) to produce gaseous

nitrogen and water. Equation 2 shows the reaction
and the enthalpy change.
2 N2H4(ℓ) + N2O4(ℓ) → 3 N2(g) + 4 H2O(g)
∆H° = -1040 kJ mol-1

1. Which of the following Lewis structures best
represents hydrazine?
A)

B)

C)

Equation 2
Some thermochemical data for hydrazine and
dinitrogen tetroxide are given in Table 1.
Table 1 Properties of Hydrazine and Dinitrogen
Tetroxide at 298 K
Property
N2H4(ℓ)
N2O4(g)
∆Hf° (kJ mol-1)
50.6
9.2
-1
∆Gf° (kJ mol )
149.2
97.9
-1
-1

S° (J K mol )
121.2
304.3

D)

2. How many grams of ammonia are required to
make one mole of hydrazine by the Raschig
process?
A) 8.5 g
B) 17.0 g
C) 32.0 g
D) 34.0 g

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5


3. What is the percent by weight of hydrazine in
hydrazine hydrate?
A) 6.0/50.0 x 100%
B) 18.0/32.0 x 100%
C) 18.0/50.0 x 100%
D) 32.0/50.0 x 100%
4.
What is the enthalpy change (∆Ho) for the
reaction shown above?
A) 50.6 kJ mol-1
B) 149.2 kJ mol-1

C) (149.2 + 298 x 121.2) kJ mol-1
D) (149.2 - 50.6) kJ mol-1
5. As a result of being a weaker base than
ammonia, hydrazine:

6. The formation of hydrazine from its elements is
NOT a spontaneous process at 25oC and 1 atm
because:
A) ∆So for the reaction is > 0.
B) ∆Ho for the reaction is < 0.
C) ∆Go for the reaction is > 0.
D) So for hydrazine is > 0.
7. The entropy change (∆So) for the reaction shown
in Equation 2 is:
A) < 0 because the moles of gaseous products > the
moles of gaseous reactants.
B) < 0 because water is a product of the reaction.
C) > 0 because the moles of gaseous products > the
moles of gaseous reactants.
D) > 0 because water is a product of the reaction.

A) has a smaller acidity constant (Ka) than does
ammonia.
B) has a smaller basicity constant (Kb) than does
ammonia.
C) can be protonated twice to form N2H62+.
D) forms hydrogen bonds in aqueous solution.

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6


Passage II
A gas of electrically charged and neutral particles is
called a plasma. Plasma physics is a broad term
applicable to such diverse areas as space physics,
gas lasers, gaseous electronics, and controlled
thermonuclear fusion.
A plasma has the ability to oscillate and propagate
waves. These waves can be excited by applying an
oscillating electric field to the plasma. The simplest
oscillation is a high-frequency oscillation of the
plasma electrons. Consider a plasma that is
electrically neutral, consisting of positive ions
immersed in a “sea” of electrons. If the electron
sea is slightly displaced from the ionic background,
electric fields act to restore the electrons to their
original equilibrium positions. The electron sea
subsequently moves toward the equilibrium
position, overshoots, and oscillates back and forth.
These oscillations are so rapid that the positive ions
seem to be fixed in the background (see Figure 1).
The frequency f at which these oscillations occur for
a given number density, n (electrons per cubic
meter), is
2

1/2

f = [kne /(πm)]

1/2

≈ 9.0n

where e and m are the elementary charge and
electron mass, 1.6 x 10-19 C and 9 x 10-31 kg,
respectively. The constant k = 9 x 109 Nm2/C2
occurs in Coulomb’s law. The approximation on
the right side of the equation gives the frequency in
Hz, when n is expressed in m-3.

Figure 1 Positive ions surrounded by a sea of
mobile electrons (gray denotes the electron sea).
A and C denote the oscillation extremes.
8. Why can the positive ions be considered to be
fixed during the electrons’ oscillations?
A) The ions are bound together with strong nuclear
forces.
B) An ion is much more massive than an electron.
C) The ions experience no force when the electron
sea is displaced.
D) Coulomb’s law prohibits the motion of the ions.
9. In Figure 1, the maximum electrical potential
energy occurs at:
A) A only.
B) B only.
C) C only.
D) A and C only.

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7


10. The density of a typical laboratory plasma is
1018 m-3. This value leads to plasma
oscillations at:

12. As the Figure 1 electrons oscillate through
equilibrium point B, they move on to C because
of:

A) 9 x 1018 Hz.
B) 9 x 1012 Hz.
C) 9 x 109 Hz.
D) 9 x 106 Hz.

A) the momentum gathered as they moved from
point A.
B) Coulomb forces pulling on the electron sea.
C) magnetic forces of attraction between the
positive ions and the electron sea.
D) the large potential energy they have at point B.

11. A plasma wave moving through a plasma has a
frequency of 109 Hz and a speed of 3.0 x 107
m/s. What is the wavelength of this wave?
A) 3.0 cm

B) 3.0 m
C) 3.3 cm
D) 3.3 m

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13. What best describes changes that occur as the
electron sea moves from position A to position
B in Figure 1?
A) Kinetic energy is transformed into potential
energy.
B) Potential energy is transformed into kinetic
energy.
C) Power is dissipated as heat.
D) Turbulence brings the electron sea to rest.

8


Passage III
Silicon, the second most abundant element in the
earth’s crust, is found combined with oxygen in a
variety of silicate minerals. The most common is
silica (SiO2), which is a network solid.
Silicon cannot be purified by electrolytic
techniques. When elemental potassium became
available in the nineteenth century, it was used in a
silicon purification procedure. Today, silicon is
produced commercially by the reaction of silica
with carbon or calcium carbide in an electric

furnace at 2000°C (Equation 1). The product is
about 98% pure, with impurities of iron, oxygen,
aluminum, and other elements. Further purification
is achieved by halogenating the silicon, purifying
the resulting gas by fractional distillation, and then
reducing the halogenated silicon compound
(Equations 2-3).
SiO2(s) + 2 C(s) → Si(ℓ) + 2 CO(g)
Equation 1
Si(s) + 3 HCl(g) → SiCl3H(g) + H2(g)
Equation 2
SiCl3H(g) + H2(g) → Si(s) + 3 HCl(g)

15. What is the electron configuration for a groundstate silicon atom?
A) [Ne] 3s
B) [Ne] 3s
C) [Ne] 3s
D) [Ne] 3s

↑↓
↑↓
↑↓
↑↓

3p ↑↑ __
3p ↑ ↓ _
3p ↑↓ __ _
3p↓ ↓ ↓

16. According to valence shell electron pair

repulsion (VSEPR) theory, what is the
geometry around silicon in SiCl3H?
A) Linear
B) Tetrahedral
C) Trigonal bipyramidal
D) Octahedral
17. Which of the following elements could best
substitute for potassium in the purification of
silicon?
A) H2
B) Na
C) Mg
D) Ca
18. SiCl3H has a normal boiling point of 33oC.
What are the predominant forces between
SiCl3H molecules?

Pure silicon is a hard, brittle, nonreactive substance
with a metallic luster.

A) Ionic forces
B) Covalent bonds
C) Hydrogen bonds
D) van der Waals forces

14. The purification of elemental silicon was
difficult to achieve because it:

19. SiCl3H is purified by fractional distillation.
Why does this procedure effect a purification?

A) is a rare element.
B) is too reactive to isolate easily.
C) exists in minerals that do not decompose easily.
D) does not crystallize.

A) SiCl3H is not water soluble.
B) SiCl3H is decomposed by water.
C) SiCl3H has a lower boiling point than the solid
impurities.
D) SiCl3H has a lower melting point than the
impurities.

Equation 3

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9


Passage IV
The production of electrical power via nuclear
fission reactions often provokes heated discussions
about nuclear waste disposal. In a typical uranium
fission, a uranium nucleus absorbs a neutron and
undergoes fission, as illustrated in the reaction
.
The superscript denotes the atomic mass and the
subscript the atomic number. The nucleus U-236
(i.e., 236U) decays immediately into two fission

fragments X and Y, along with the release of two or
three neutrons. Energy is produced in the fission
process by the conversion of nuclear mass into
energy. This conversion is described by Einstein’s
famous relation E = mc2, where c is the speed of
light 3 x108 m/s, m is the mass that is converted,
and E the resulting energy released. An analysis of
the reaction shown reveals that about 1/1000 of the
original starting mass of U-235 is missing after the
reaction. This missing mass accounts for the energy
produced in the reaction. The fission fragments X
and Y constitute the radioactive waste from
uranium fission. These fragments then undergo
beta and/or gamma decay. The resulting fragments
themselves may be radioactive, resulting in further
decays until a stable isotope is reached. Hundreds
of years must pass before these radioactive
fragments decay to nonradioactive nuclei.

20. If three neutrons are produced in the U-235
fission reaction discussed in the passage, what
relation must the atomic masses A1 and A2
obey?

21. If fission fragment X undergoes beta decay,
then one neutron in the nucleus is converted
into a proton, an electron and a neutrino (the
electron and neutrino v′exit the atom). If the
new fission fragment is called X ′, the betadecay reaction would be written as:
A)

B)
C)
D)
22. Half-lives are useful indicators of how
dangerous a radioactive substance is. The halflives of Pu-239 and Ra-226 are 24,000 yrs and
1600 yrs, respectively. In comparison to atoms
of Pu-239, atoms of Ra-226 will decay at a
rate:
A) 8 times faster.
B) 15 times faster.
C) 8 times slower.
D) 15 times slower.
23. A standard coal-burning power plant produces
about 106 kg of fly-ash every week. Assuming
that the density of fly-ash is 1000 kg/m3, what
would be the length of the side of a fly-ash
cube made from this waste?
A) 1 m
B) 10 m
C) 100 m
D) 1000 m

A) A1 + A2 = 92
B) A1 + A2 = 232
C) A1 + A2 = 233
D) A1 + A2 = 236

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10

24. Consider the following electrode potentials.
Cu2+ + 2 e- → Cu(s)

Eo= +0.34 V

2 H2O → O2 + 4 H+ + 4 e-

Eo = -1.23 V

What is Eocell for the reaction shown in the
following equation?
2 Cu2+ + 2 H2O → 2 Cu(s) + O2 + 4 H+
A) -0.89 V
B) +0.55 V
C) +1.57 V
D) +1.91 V
25. A gas that occupies 10 L at 1 atm and 25oC will
occupy what volume at 500 atm and 25oC?
These questions are not based on a descriptive
passage and are independent of each other.

A) Exactly 0.020 L
B) Somewhat more than 0.02 L because of the
space occupied by the individual gas molecules
C) Somewhat more than 0.02 L because of the
repulsions between the individual gas molecules
D) Somewhat more than 0.02 L because of the
increased number of collisions with the sides of

the container
26. If there is no air resistance, how far will a 2-kg
object fall from rest in 10 sec? (Note: Use g =
10 m/s2.)
A) 100 m
B) 250 m
C) 300 m
D) 500 m
27. When a light wave and a sound wave pass from
air to glass, what changes occur in their speeds?
A) Both speed up.
B) Both slow down.
C) Light speeds up; sound slows down.
D) Light slows down; sound speeds up.

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11


Passage V
When aqueous solutions of bromine and acetone are
mixed, the reaction shown by Equation 1 occurs.

Table 1 gives rate data for this reaction. In the
experimentally determined rate law, the reaction is
zero order with respect to bromine.
Table 1 Rate Data at 25°C and 395 nm

Equation 1

Exprmnt
Number

[acetone]
M

[H+]
M

[Br2]
M

1

1.60

0.403

4.14 × 10−3

0.101

3.96 × 10

−3

3.69 × 10

−3

4.26 × 10

−3

4.38 × 10

−3

4.28 × 10
–1 –1

−3

2

When the pH of the solution is between 4 and 7, the
reaction occurs very slowly. However, at pH values
less than 3, the reaction occurs rapidly.
If the bromination of acetone (molar mass = 58.0 g
mol–1 and density = 0.791 g mL–1) follows simple
kinetics, the rate law can be expressed by
Equation 2.
a

b

+ c

Rate = –∆[Br2]/∆t = k[acetone] [Br2] [H ]

Equation 2

Bromine is a red–brown liquid that absorbs light
very strongly at a wavelength of 395 nm, and it is
the only compound that absorbs visible light during
this reaction. Thus, a researcher can use a
spectrophotometer to follow the decrease in the
concentration of bromine. The amount of 395-nm
light absorbed by bromine is directly proportional to
the concentration of bromine. Equation 3 is Beer’s
law, which shows the relationship between the
absorbance A and the concentration c of the
absorbing species when light passes through a
cuvette of path length l. The molar absorbtivity ε is
a constant for a given wavelength, and the path
length is normally 1.00 cm.
А = ε cl
Equation 3

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3
4
5
6

0.80
0.40
0.80
1.60

0.80

0.202
0.403
0.202
0.202
–5

kave = 3.86 ± 0.2 × 10 M

– ∆[Br2]/∆t
M s–1

rate
constant
k× 10–5

28.0 × 10–6

4.35

2.85 × 10

–6

3.52

2.94 × 10

–6

3.65

12.9 × 10

–6

4.00

12.7 × 10

–6

3.93

5.99 × 10

–6

3.70

s

28. The molar absorptivity of bromine at 395 nm is
198 M–1 cm–1. What is the absorbance at 395
nm in Experiment 1?
A) 0.00825
B) 0.820
C) 1.22
D) 20.9

29. What is the value of c in Equation 2 as
determined from the data in Table 1?
A) 1
B) 2
C) 3
D) 4
30. If the reaction is first order with respect to both
acetone and hydronium ion, which of the
following equations gives the rate law?
A) Rate = k[acetone][H+]
B) Rate = k[acetone][Br2]2[H+]
C) Rate = k[acetone][Br2][H+]
D) Rate = k[acetone]2[H+]

12


31. What is the molarity of pure acetone?
A) 1.36 M
B) 13.6 M
C) 45.9 M
D) 73.4 M

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32. Though 395-nm light is in the visible region of
the electromagnetic spectrum, it is very near:
A) the radio wave region.
B) the microwave region.
C) the infrared region.

D) the ultraviolet region.

13


Passage VI
Cellular phones are commonly used by people who
are traveling away from home or on business. The
development of these phones combines many recent
innovations in technology. Simply described,
cellular phones behave like two-way radios with the
incoming voice data transmitted at one carrier
frequency and the outgoing voice data transmitted
at another frequency. This capability to send and
receive voice data on these two separate frequency
channels allows the person to hear and speak on the
phone at the same time. The information in these
channels is transmitted on radio-frequency
electromagnetic carrier waves, which travel well
through the air.
Cell-phone channels operate at frequencies ranging
between 824 MHz and 894 MHz. Each channel
requires a finite amount of frequency space, called
the bandwidth of the channel, and is set at 30 kHz.
Most cellular phones can transmit their signal with
between 0.6 watts and 3 watts of power. The cell
phone scans all of its channels when it is on to find
the channel with the highest signal intensity. The
phone communicates with a base station, which
typically covers an area of 10 square miles, called a

“cell.” A cellular city has many “cells” within it,
which have phone base stations to transmit and
receive cell-phone data. Because the size of a cell
is relatively small, it allows efficient
communication with relatively low power phones.
When a phone moves from cell to cell, its calls are
handled by a central switching office.
33. What is the total frequency range available for
cellular phone communications?
A) 30 kHz
B) 894 MHz
C) 70 MHz
D) 894.03 MHz

34. If a cellular phone is powered by a 12-volt
battery and is transmitting at its maximum
power, what current is being used?
A) 3 W
B) 3 A
C) 0.25 A
D) 0.05 A
35. If two people were talking on their cellular
phones within the same "cell" in a city, why
wouldn't their transmissions interfere?
A) The power transmitted from each phone is not
high enough to interfere.
B) The signals are transmitted at the speed of light,
and do not have time to interfere.
C) The physical distance between any two base
stations limits interference.

D) The frequencies used by each phone are chosen
to be different.
36. The intensity of a cellular phone transmission
received at the switching station is proportional
to the power used by the phone and inversely
proportional to the square of the distance
between phone and station. Which combination
of power and distance will provide the highest
signal to be picked up by the switching station?
A) 0.6 watts, 2 miles
B) 0.6 watts, 3 miles
C) 3 watts, 5 miles
D) 3 watts, 4 miles
37. The 846 MHz carrier wave is an
electromagnetic signal, whereas sounds waves
are typically at much lower frequency and are
carried through the air as pressure waves.
Which statement describes the two waves
accurately?
A) Electromagnetic waves are transverse; pressure
waves are longitudinal.
B) Electromagnetic waves are longitudinal;
pressure waves are transverse.
C) Waves are always longitudinal and transverse.
D) Electromagnetic wavelengths are longer than
acoustic sound wavelengths.

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14

Passage VII
A capacitor is a device that stores charge. The
voltage V across a capacitor and the charge q on the
capacitor are related by q = CV, where C is the
capacitance measured in farads, F (1.0 F = 1.0
coulomb per volt).
A student sets out to measure the capacitance using
the circuit of Figure 1.

38. When switch S is closed to the left, charge
begins to accumulate on the capacitor. Charge
cannot accumulate indefinitely because:
A) the variable resistor inhibits the current flow.
B) the battery continually loses charge.
C) successive charges brought to the plates are
repelled by charges accumulated earlier.
D) the fixed resistor loses energy to heat.
39. To keep the current constant during the
discharge cycle:

Figure 1 Circuit for measuring capacitance
In this circuit, the capacitor will be fully charged
soon after switch S is closed to the left, as current
passes through the small fixed resistor r in series
with the capacitor C. Then, when S is switched to
the right, the capacitor discharges through the
variable resistor R. R is adjusted so that the
discharge current, as measured by the ammeter, is

constant during the discharge time.

A) the resistance R must be continually increased.
B) the resistance R must be continually decreased.
C) the resistance r must be continually increased.
D) the resistance r must equal R.
40. As the capacitor is charged, the electrical
potential energy that it gains:
A) equals the work done by the battery throughout
the charging process.
B) is less than the work done by the battery
throughout the charging process.
C) is greater than the work done by the battery
throughout the charging process.
D) equals the potential energy stored in resistor r.
41. Which circuit elements store energy?
I.
II.
III.

Figure 2 The discharge current versus time
Figure 2 shows the current-versus-time plot during
the discharge. The voltage of the battery used in the
measurement was 12.0 V. The total charge q
transferred to the capacitor can be estimated from
the constant current value during the discharge time.

Capacitors
Resistors
Batteries

A) I only
B) I and II only
C) I and III only
D) II and III only
42. The resistance of the variable resistor, R, at the
beginning of the discharge process is:
A) 2000 Ω.
B) 3000 Ω.
C) 4000 Ω.
D) 6000 Ω.

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15


The exchange of oxygen-18 between H218O and
SO42- is also more rapid in acid than in neutral
solutions of SO42-. A proposed reaction mechanism
for the exchange is shown below.

Passage VIII
Many reactions of oxyanions (negative ions that
contain oxygen) involve the transfer of oxygen
atoms from one ion or molecule to another.
Reaction 1 shows an oxygen atom transfer that is
typical of an oxyanion reaction.
NO2- + OCl-

NO3- + Cl-

Keq = 1068

Reaction 1
Despite the favorable equilibrium constant, this
reaction is extremely slow. The reaction rate can be
increased by adding acid to the reaction solution.
When added, acid reacts with OCl-, forming HOCl.
HOCl allows the oxygen transfer to take place more
quickly because the hydrogen atom reduces the
charge on the oxygen atom, facilitating the breaking
of the O-Cl bond. The rate of this reaction,
Reaction 2, is first order in both NO2- and HOCl.
NO2- + HOCl

NO3- + Cl- + H+

Keq = 1043

Reaction 2
Other oxyanion reactions also take place more
quickly in acidic solutions. For example, no
observable reaction occurs between ClO3- and Br- in
basic solution, but when an acidic solution is used,
Reaction 3 occurs rapidly.
ClO3- + 6 Br- + 6 H+ → Cl- + 3 Br2 + 3 H2O
Reaction 3
The rate law for Reaction 3 is k[ClO3-][Br-][H+]2,
and the initial sequences of the reaction mechanism

are shown below.
Sequence I
Sequence II
Sequence III

2 H+ + ClO3Br- + H2OClO2+
Br- + BrClO2

H2OClO2+
BrClO2 + H2O
Br2 + ClO2-

(fast)
(slow)
(fast)

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Sequence I
Sequence II
Sequence III

2 H+ + SO42H2SO4
SO3 + H218O

H2SO4
SO3 + H2O
2 H+ + SO318O2-

(fast)

(slow)
(fast)

43. If the rate of formation of Cl- in Reaction 3
were 1.0 x 10-2M/sec at a pH of 1, what would
it be at a pH of 2? (Note: Assume that other
conditions are identical.)
A) 1 x 10-1M/s
B) 1 x 10-2M/s
C) 2 x 10-2M/s
D) 1 x 10-4M/s
44. Compared to the rate of Reaction 1, the rate of
Reaction 2:
A) is 1025 times less.
B) is 1025 times greater.
C) is 1.58 times greater.
D) cannot be evaluated without additional
information.
45. In addition to the explanation in the passage,
the rate of Reaction 2 is different from the rate
of Reaction 1 because the formation of HOCl
by the protonation of the oxygen:
A) reduces the electronic repulsion forces between
the reactants.
B) increases the electronic repulsion forces between
the reactants.
C) increases the electronic repulsion forces between
the nitrogen atom and the oxygen atom that is
being transferred.
D) reduces the electronic attraction forces between

the chlorine atom and the oxygen atom that is
being transferred.

16


46. Which of the following methods would produce
SO318O2- at the fastest rate?
A) Bubbling SO3(g) through H218O
B) Bubbling S18O3(g) through H218O
C) Bubbling S18O3(g) through H2O
D) Reacting SO218O(l) with H218O

48. Which of the following graphs best shows the
energy diagram for the Reaction 3 mechanism
in the passage?
A)

47. Which of the following figures represents a
likely transition state for Reaction 2?
A)
B)

B)

C)

C)

D)

D)

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17


These questions are not based on a descriptive
passage and are independent of each other.
49. Phosphorus appears directly below nitrogen in
the periodic table. The boiling point of
ammonia, NH3, is higher than the boiling point
of phosphine, PH3, under standard conditions.
Which of the following statements best
explains the difference in the boiling points of
these two compounds?
A) Ammonia is a weaker base than phosphine.
B) The N-H bond is weaker than the P-H bond.
C) High molecular weight compounds generally
have lower boiling points.
D) Ammonia forms stronger intermolecular
hydrogen bonds than phosphine.
50. A student measures the mass and volume of
four objects.
Object Mass(g) Volume(cm3)
A
1.5
0.50
B

3.0
0.75
C
4.5
1.00
D
6.0
1.50
Which object has the highest density?
A) A
B) B
C) C
D) D

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51. Which of the following elements gains one
electron most readily?
A) Be
B) Cl
C) K
D) Ca
52. Which of the following substances is NOT a
base?
A) NH3
B) SO42C) NH4+
D) Fe(OH)2
53. A ray of light in air is incident upon a glass
plate at an angle of 45o. The angle of refraction
of the ray in the glass is 30o. What is the index

of refraction of the glass?
(Data: sin 30o= 0.500, sin 45o= 0.707,
sin 60o= 0.866, tan 30o= 0.577,
tan 45o= 1.000)
A) 1.22
B) 1.41
C) 1.57
D) 1.65

18


Passage IX
Generalizations such as “like dissolves like” and
“the solubility of a solute doubles for every tendegree rise in temperature” are useful in certain
situations but are not universally applicable to
solution chemistry. Instead, several different
relationships describe solution dynamics. Thus,
depending on the problem, a chemist must use
various concentration units.
For example, molarity (M) is best for most
stoichiometry problems, molality (m) for freezingpoint depression problems, mole fraction for
Raoult-law problems, and osmolality for osmotic
pressure problems.

54. What is the molality of a saturated solution of
Pb(NO3)2(aq) at 0oC?
A) 0.114 m
B) 0.251 m
C) 1.14 m

D) 3.41 m
55. To what temperature does a 10.75 m solution of
ethylene glycol protect an engine from
freezing?
A) -5.78oC
B) -12.0oC
C) -20.0oC
D) -45.0oC

Table 1 gives data for two water soluble solutes,
ethylene glycol [C2H6O2(ℓ)] and lead nitrate
[Pb(NO3)2(s)].

56. Which aqueous solution, 0.1 M lead nitrate or
0.1 M ethylene glycol, lowers the freezing point
of water to a greater extent?

Table 1 Data for Ethylene Glycol and Lead Nitrate

A) Pb(NO3)2(aq) by threefold
B) Pb(NO3)2(aq) by twofold
C) C2H6O2(aq) by twofold
D) C2H6O2(aq) by threefold

Property
Formula weight
Specific gravity
Solubility in
water at 0°C at
20°C

C2H6O2
62.1 g/mol
1.116

Pb(NO3)2
331 g/mol
4.53

∞
∞

37.7 g/100mL
56.5 g/100mL

Equation 1 shows how osmotic pressure (II)
depends on concentration (M) and Kelvin
temperature (T).

57. Does either generalization in the passage apply
to aqueous solutions of ethylene glycol?
A) Yes; both generalizations apply.
B) No; neither generalization applies.
C) Yes; “like dissolves like” only applies.
D) Yes; “the solubility of a solute doubles for every
ten-degree rise in temperature” only applies.

II = MRT
Equation 1
Note: R = 0.082 L atm K-1 mol-1, and the molal

freezing-point depression and boiling-point
elevation constants for water are Kf = -1.86°C/m
and Kb = 0.52°C/m, respectively.

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58. If a cell wall separates a hypertonic, interstitial
fluid from cellular fluid, will there be an
osmotic effect?
A) Yes; the cell fluid will become less
concentrated.
B) Yes; the cell fluid will become more
concentrated.
C) No; osmosis does not apply to biological fluids.
D) No; the concentrations are the same on both
sides of the wall.

19


59. What kind of solution results if a chemist
equilibrates 39.0 g of lead nitrate in 100 mL of
H2O at 0oC over several days?
A) A saturated solution with 3.9 g of undissolved
salt
B) A saturated solution with 1.3 g of undissolved
salt
C) An unsaturated solution
D) A supersaturated solution

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60. What is the mole fraction of lead nitrate in a
10% (wt-wt) aqueous solution?
A) 0.006
B) 0.03
C) 0.1
D) 0.6

20


Passage X
Cars are subjected to many forces as they move: air
drag, tire-road friction, engine motive force, gravity,
and other factors. Unfortunately, collisions
occasionally occur. During such accidents, a
(potentially large) fraction of the kinetic energy is
rapidly and irreversibly converted to thermal energy
and deformation of the car structure. Test crashes
with dummy drivers and passengers and other
experiments help designers develop safer vehicles.
In one test, two 1000-kg cars, A and B, are initially
100 m apart. They are traveling on a highway in the
same direction: car A at 30 m/s, car B at 20 m/s
with car B ahead of car A. Eventually they collide.
In one case the collision is cushioned by a spring
(with constant k = 105 N/m) on the front of car A.
In a second case there is no spring and the body
deformation of the two cars absorbs the collision

energy. (Assume g = 10 m/s2 when needed.)
61. Consider the difference in crash deceleration on
a test dummy in two test cases.

62. Two cars, each of mass 1000 kg traveling at 20
m/s in opposite directions, have a head-on
inelastic collision. How much heat and
deformation energy is produced?
A) 2 x 105 J
B) 4 x 105 J
C) 8 x 105J
D) 16 x 105 J
63. When tires are made of hard rubber, the
coefficients of rolling, sliding, and static
friction with the road are reduced compared
with softer rubber. Which of the following
predictions would NOT hold if hard rubber
replaced soft rubber in tire manufacture?
A) Stopping distances would increase.
B) Fuel efficiency would be unchanged.
C) Slippage on curves would be more likely.
D) Higher tire air pressure would be required.
64. A spring between colliding cars reduces the
average force on the cars because it:

Case I: The dummy hits the steering wheel at
20 m/s and stops in 0.1 s.
Case II: The dummy hits an air bag at 20 m/s
and stops in 0.25 s.

A) lengthens collision time.
B) absorbs kinetic energy loss.
C) absorbs momentum change.
D) causes no permanent deformation.

What is the ratio of the average acceleration in
Case II to that in Case I?

65. How long before test car A overtakes car B?

A) 0.25
B) 0.40
C) 2.5
D) 4.0

A) 2 s
B) 3.33 s
C) 5 s
D) 10 s
66. What is the post-collision speed of cars A and
B after the no-spring inelastic collision?
A) 0 m/s
B) 20 m/s
C) 25 m/s
D) 50 m/s

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21

Passage XI
Worldwide, about 20 damaging earthquakes occur
daily. A major quake in the Mojave Desert (near
Landers) in 1992 demonstrated that large quakes
sometimes trigger distant smaller ones. Of the
many seismographs installed throughout the West in
the 1980s, 14 recorded local quakes after the
Landers event, making coincidence an unlikely
explanation.
The Landers quake produced measurable lasting
deformations over a length L = 74 km. L is called
the source length of the initiating quake. Allied
quakes, aftershocks, occur within a distance of 2L
from the primary event. However, triggered quakes
were as far away as 17L.
The mechanism of the triggering is a puzzle. It is
useful to categorize seismic waves into two kinds:
deeply propagating body waves, which dissipate
rapidly with distance, and surface waves, which
dissipate at a lesser rate. Lasting deformations from
a quake are produced by the body waves, with
deformation size falling off as (L/d)3, where d is
distance from the quake center. At d = 4L these
deformations are generally reduced to less than the
daily periodic distortions due to tidal forces. On the
other hand, surface waves are associated with
elastic oscillations in the crust of about 10-s
periodicity and cause little lasting deformation.
Some of the time delays between the Landers quake

and those it triggered were too great to be ascribed
to seismic wave-transit times.
One explanation of the aftershock trigger
mechanism involves underground fluids, water or
molten rock. Fluid seals between isolated volumes
of rock at different pressures may leak, thus
increasing transverse frictional forces. Also, fluid
may flow into rock fractures, thus lubricating them.

67. Before the Landers quake, coincidence was
argued as a sufficient explanation for what is
now believed to be triggered-quake events. For
these earlier events, which of the following
does NOT support the coincidence hypothesis?
A) The timing of subsequent quakes provided
ambiguous evidence.
B) Generally, the distances to the subsequent
quakes was excessive.
C) Too few of the subsequent quakes were recorded
to establish a clear connection.
D) Generally, the subsequent quakes were scattered
in all directions.
68. What is the ratio of lasting deformations
produced by a quake at 16 L from its center to
those produced at 4 L from its center?
A) 1/16
B) 1/32
C) 1/64
D) 1/128
69. Because earthquakes were triggered by what

ultimately must have been comparatively minor
energy transfers from the distant Landers
quake, the triggered quakes probably occurred
where:
A) significant local stress forces in the earth’s crust
were already in precarious equilibrium.
B) the earth’s crust was subjected to reinforcing
resonant effects that cumulatively built up local
stresses.
C) the earth’s crust locally sustained standing wave
nodes for a short but significant period.
D) destructive interference effects in the incoming
seismic waves were approximately maximum
for an extended period.
70. The wavelength of surface waves is about 20
km. The propagation speed of these waves is
estimated as:
A) hundreds of m/s.
B) thousands of m/s.
C) tens of thousands of m/s.
D) hundreds of thousands of m/s.

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22


71. The primary rupture in the Landers quake
moved from south to north as it progressed to
its full 74-km length. How would the Doppler

effect influence this?
A) By decreasing the wavelength of seismic waves
propagating eastward and westward
B) By increasing the wavelength of seismic waves
propagating eastward and westward
C) By decreasing the wavelength of seismic waves
moving northward and increasing the
wavelength of waves moving southward
D) By increasing the wavelength of seismic waves
moving northward and decreasing the
wavelength of waves moving southward

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23


These questions are not based on a descriptive
passage and are independent of each other.

72. What is the difference in pressure between two
points that are separated by a vertical distance
of 0.25 m in a tank of water? (Note: The
density of water is 1,000 kg/m3, and g = 10
m/s2.)
A) 250 N/m2
B) 400 N/m2
C) 2,500 N/m2
D) 4,000 N/m2
73. The following reaction occurs spontaneously.

Cd(s) + 2 H+(aq) → Cd2+(aq) + H2(g)
Which of the following has the highest electron
affinity?
A) Cd(s)
B) H+(aq)
C) Cd2+(aq)
D) H2(g)
74. The energy, E, of a hydrogen atom with its
electron in the nth shell of a hydrogen atom is
given by E = -C/n2 where n = 1,2,3, . . . and C
is a positive constant. If an electron goes from
the n = 2 shell to the n = 3 shell:

75. A ray of light in air strikes the flat surface of a
liquid, resulting in a reflected ray and a
refracted ray. If the angle of reflection is
known, what additional information is needed
in order to determine the relative refractive
index of the liquid compared to air?
A) Angle of incidence
B) Angle of refraction
C) Refractive index of air
D) Wavelength of the light
76. Approximately how many moles of Al3+ are
reduced when 0.1 faraday of charge passes
through a cell during the production of Al?
(Note: Assume there is excess Al3+ available
and that Al3+ is reduced to Al metal only.)
A) 0.033 mol
B) 0.050 mol

C) 0.067 mol
D) 0.10 mol
77. When a weak acid (HA) is titrated with sodium
hydroxide in the presence of an indicator (HIn),
the pH at which a color change is observed
depends on the:
A) final concentration of HA.
B) final concentration of HIn.
C) initial concentration of HA.
D) pKa of HIn.

A) a photon is emitted.
B) an electron is emitted.
C) an electron is absorbed.
D) the energy of the atom is increased.

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24


Verbal Reasoning
Time: 85 minutes
Questions: 78-137
There are nine passages in the complete Verbal Reasoning test. Each passage is followed by several questions.
After reading a passage, select the one best answer to each question. If you are not certain of an answer,
eliminate the alternatives that you know to be incorrect and then select an answer from the remaining
alternatives. Indicate your selected answer by marking the corresponding answer on your answer sheet.

This document has been encoded to link this download to your member account. The AAMC and its Section

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