AAMC FL 4
Limestone does NOT decompose when heated to 900 K because, at 900
K, ΔH is:
A. Positive and less than
TΔS
B. Positive and greater than
TΔS
C. Negative and less than
TΔS
D. Negative and greater than TΔS correct
answersB.
The reaction does not occur (is not spontaneous). This indicates that the ΔG
=ΔH-TΔS
>0. From inspection of the reaction, it can be concluded that ΔS>0.
Consequently,
ΔH>TΔS explains why the reaction does not
occur
When limestone is heated during Step 1, an equilibrium is established.
Which of the following expressions is the equilibrium constant for the
decomposition of limestone?
A.
[CaO]
B.
[CaCO3]
C.
[CO2]
D. [CaO] x [CaCO3] correct
answersC.
From the law of mass action, an equilibrium constant expression involves
a ration ofto reactants with exponents determined from the stoichiometry of
products
the reaction. solids are excluded from equilibrium constant expressions.
Furthermore,
the
CO2only(g), non-solid
as material in the reaction, is the only substance that
appears in the
equilibrium constant
expression.
During Reaction 2, did the oxidation state of N
change?
A. Yes; it changed from -3
to -4
B. Yes; it changed from 0
to +1
C. No; it remained
at -3
D. No; it remained at +1 correct
answersC.
The part of the Reaction 2 that involves nitrogen is the protonation of
ammonia
H--> NH4+).(NH3 +
Acid-base reactions doe not involve oxidation state changes.
the oxidation states of N in NH3 is -3
Furthermore
not 0.
If all of Gas X (from Step 6) is held in a sealed chamber at STP, what
will be its
appropriate
volume?
A. 22.4
B. 44.8
L
L
C. 67.2
L
D. 89.6 L correct
answersA.
The quantity of Gas X was given as 1 mole. One mole of gas occupies 22.4
L at STP.
,Why was it important that the cuvettes containing the glucose oxidase
and the were
sample bloodidentical in terms of optical
properties?
A. To enable the comparison of the absorption
spectra
B. To reduce the absorption in the glass
walls
C. To decrease the uncertainty in the
wavelength
D. To increase the absorption in the solutions correct
answersA.
The identical optical properties of the cuvettes ensure that the absorbed
radiation
only to theis presence
due of glucose in the blood and not due to the
difference in
absorption the
features of the
walls.
What is the approximate energy of a photon in the absorbed radiation that
yielded
data the
in Table
1?
A. 1
eV
B. 2
eV
C. 3
eV
D. 4 eV correct answersB. ( I
chose C)
The photon energy is E=hc/λ = 19.8 x 10^-26 J.m/ (625 x 10^-9) = 3.1
x10^-19
about 2 J , so
eV
According to Table 1, what is the concentration of the glucose in the blood
fromdiluted
the which sample was
taken?
A. 60
mg/dL
B. 90
mg/dL
C. 120
mg/dL
D. 150 mg/dL correct
answersD.
From Table 1, the glucose concentration in the diluted sample is (o.20/0.24) x
6.05.0
= mg/dL
mg/dL.
The blood then has a glucose concentration of 30 x 5.0 mg/dL=
150 mg/dL.
Suppose a blood sample tested above the range (6.0 mg/dL) of the
standards
the experiment.
used in What modification will provide a more precise
reading by data
interpolation as opposed to extrapolation using the same
standards?
A. Increase the enzyme
concentration.
B. Increase the oxygen
pressure.
C. Decrease the content of the oxygen
acceptor
D. Dilute the sample with additional solvent. correct
answersD.
,By adding solvent, the concentration of glucose will be lowered, and
the resultingwill fall within the range of the standards. This is easily
absorbance
accomplished,
the and
resulting calculations that account for the dilution are
not difficult.
Which of the following reasons best explains why it is possible to separate a
1:11-chlorobutane
of mixture and 1-butanol with fractional
distillation?
A. Both 1-chlorobutane and 1-butanol are
polar
B. Both 1-chlorobutane and 1-butanol are
nonpolar
C. The boiling point of 1-chlorobutane is substantially higher than that
of 1-butanol
D. The boiling point of 1-chlorobutane is substantially lower than that
of 1-butanol
correct
answersD.
The fact that 1-chlorobutane will have a boiling point that is substantially
lower
of than that
1-butanol can be rationalized from chemical principles. The molecules
have similar
molecular weights, but 1-butanol has a hydroxyl functional group that can
participated
hydrogen in
bonding. Hydrogen bonding is a particularly strong force of
intermolecular
attractio
n.
Which of the following oxidative transformations is unlikely
to occur?
A. A primary alcohol to an
aldehyde
B. A tertiary alcohol to a
ketone
C. An aldehyde to a carboxylic
acid
D. A secondary alcohol to a ketone correct
answersB.
Oxidation of tertiary alcohols is difficult because it involved C-C
bond breaking
According to the IUPAC, which is the systematic name for the
hydrocarbon shown?
A. Z-3-methylpent-2-
B. E-3-methylpent-2-
ene
ene
C. Z-3-ethylbut-2-
ene
D. E-3-ethylbut-2-ene correct
answersA.
By IUPAC rules, first identify the longest unbroken chain of carbon atoms.
Next,
the number
carbon atoms in this chain starting from the end that gives the C=C
the lowestThe double bond is identified by the portion of the carbon
numbers.
atoms from
lowest the ed (2), and then the methyl group is assigned at the 3-
numbers
position. The
stereochemical designator for the double bond is X because the highest
priority
occur ongroups
the same side of the double bond. (On Z
same side)
Two vector magnitudes |A| = 8 units and |B| =5 units make an angle that
cantovary
0° 180°from
. The magnitude of the resultant vector A + B CANNOT have
the value of:
A. 2
units
B. 5
units
, C. 8
units
D. 12 units correct
answersA.
The magnitude of A+B is as small as 3 units and as large as 13 units. The
magnitude
2 of
units is smaller than the smallest possible magnitude of
vector A+B.
What is the effect produced by the PRK technique designed
to correct
nearsightednes
s?
A. The density of the cornea is
increased
B. The radius of curvature of the cornea is
increased
C. The index of refraction of the cornea is
increased
D. The thickness of the cornea at the apex is increased correct
answersB.
According to the passage, to correct nearsightedness, the laser beam is
directed
the onto
central part of the cornea, resulting in a flattening of the cornea. This
means that the
radius of curvature of the cornea is
increased.
What is the magnitude of the electric field in the electrical discharge
producedlaser
excimer in the
tube?
A. 2.0 x 10^6
V/m
B. 4.0 x 10^5
V/m
C. 6.0 x 10^4
V/m
D. 8.0 x 10^3 V/m correct
answersA.
The magnitude of the electric field produced by 8.0 kV across 4.0 mm is
8000
m = 2.0V/ 0.004
x 10^6
V/m.
What is the frequency of the pulses that deliver laser radiation to
the cornea?
A. 0.4
Hz
B. 4.0
Hz
C. 25
Hz
D. 250 Hz correct
answersB.
The frequency is 1/250 ms =
4 Hz
The use of pulsed laser radiation in the PRK procedure, as opposed to
continuousallows
radiation, laser the
cornea to:
A. absorb more
radiation
B. change its index of
refraction
C. increase the area exposed to
radiation
D. maintain a lower average temperature correct
answersD.
Limestone does NOT decompose when heated to 900 K because, at 900
K, ΔH is:
A. Positive and less than
TΔS
B. Positive and greater than
TΔS
C. Negative and less than
TΔS
D. Negative and greater than TΔS correct
answersB.
The reaction does not occur (is not spontaneous). This indicates that the ΔG
=ΔH-TΔS
>0. From inspection of the reaction, it can be concluded that ΔS>0.
Consequently,
ΔH>TΔS explains why the reaction does not
occur
When limestone is heated during Step 1, an equilibrium is established.
Which of the following expressions is the equilibrium constant for the
decomposition of limestone?
A.
[CaO]
B.
[CaCO3]
C.
[CO2]
D. [CaO] x [CaCO3] correct
answersC.
From the law of mass action, an equilibrium constant expression involves
a ration ofto reactants with exponents determined from the stoichiometry of
products
the reaction. solids are excluded from equilibrium constant expressions.
Furthermore,
the
CO2only(g), non-solid
as material in the reaction, is the only substance that
appears in the
equilibrium constant
expression.
During Reaction 2, did the oxidation state of N
change?
A. Yes; it changed from -3
to -4
B. Yes; it changed from 0
to +1
C. No; it remained
at -3
D. No; it remained at +1 correct
answersC.
The part of the Reaction 2 that involves nitrogen is the protonation of
ammonia
H--> NH4+).(NH3 +
Acid-base reactions doe not involve oxidation state changes.
the oxidation states of N in NH3 is -3
Furthermore
not 0.
If all of Gas X (from Step 6) is held in a sealed chamber at STP, what
will be its
appropriate
volume?
A. 22.4
B. 44.8
L
L
C. 67.2
L
D. 89.6 L correct
answersA.
The quantity of Gas X was given as 1 mole. One mole of gas occupies 22.4
L at STP.
,Why was it important that the cuvettes containing the glucose oxidase
and the were
sample bloodidentical in terms of optical
properties?
A. To enable the comparison of the absorption
spectra
B. To reduce the absorption in the glass
walls
C. To decrease the uncertainty in the
wavelength
D. To increase the absorption in the solutions correct
answersA.
The identical optical properties of the cuvettes ensure that the absorbed
radiation
only to theis presence
due of glucose in the blood and not due to the
difference in
absorption the
features of the
walls.
What is the approximate energy of a photon in the absorbed radiation that
yielded
data the
in Table
1?
A. 1
eV
B. 2
eV
C. 3
eV
D. 4 eV correct answersB. ( I
chose C)
The photon energy is E=hc/λ = 19.8 x 10^-26 J.m/ (625 x 10^-9) = 3.1
x10^-19
about 2 J , so
eV
According to Table 1, what is the concentration of the glucose in the blood
fromdiluted
the which sample was
taken?
A. 60
mg/dL
B. 90
mg/dL
C. 120
mg/dL
D. 150 mg/dL correct
answersD.
From Table 1, the glucose concentration in the diluted sample is (o.20/0.24) x
6.05.0
= mg/dL
mg/dL.
The blood then has a glucose concentration of 30 x 5.0 mg/dL=
150 mg/dL.
Suppose a blood sample tested above the range (6.0 mg/dL) of the
standards
the experiment.
used in What modification will provide a more precise
reading by data
interpolation as opposed to extrapolation using the same
standards?
A. Increase the enzyme
concentration.
B. Increase the oxygen
pressure.
C. Decrease the content of the oxygen
acceptor
D. Dilute the sample with additional solvent. correct
answersD.
,By adding solvent, the concentration of glucose will be lowered, and
the resultingwill fall within the range of the standards. This is easily
absorbance
accomplished,
the and
resulting calculations that account for the dilution are
not difficult.
Which of the following reasons best explains why it is possible to separate a
1:11-chlorobutane
of mixture and 1-butanol with fractional
distillation?
A. Both 1-chlorobutane and 1-butanol are
polar
B. Both 1-chlorobutane and 1-butanol are
nonpolar
C. The boiling point of 1-chlorobutane is substantially higher than that
of 1-butanol
D. The boiling point of 1-chlorobutane is substantially lower than that
of 1-butanol
correct
answersD.
The fact that 1-chlorobutane will have a boiling point that is substantially
lower
of than that
1-butanol can be rationalized from chemical principles. The molecules
have similar
molecular weights, but 1-butanol has a hydroxyl functional group that can
participated
hydrogen in
bonding. Hydrogen bonding is a particularly strong force of
intermolecular
attractio
n.
Which of the following oxidative transformations is unlikely
to occur?
A. A primary alcohol to an
aldehyde
B. A tertiary alcohol to a
ketone
C. An aldehyde to a carboxylic
acid
D. A secondary alcohol to a ketone correct
answersB.
Oxidation of tertiary alcohols is difficult because it involved C-C
bond breaking
According to the IUPAC, which is the systematic name for the
hydrocarbon shown?
A. Z-3-methylpent-2-
B. E-3-methylpent-2-
ene
ene
C. Z-3-ethylbut-2-
ene
D. E-3-ethylbut-2-ene correct
answersA.
By IUPAC rules, first identify the longest unbroken chain of carbon atoms.
Next,
the number
carbon atoms in this chain starting from the end that gives the C=C
the lowestThe double bond is identified by the portion of the carbon
numbers.
atoms from
lowest the ed (2), and then the methyl group is assigned at the 3-
numbers
position. The
stereochemical designator for the double bond is X because the highest
priority
occur ongroups
the same side of the double bond. (On Z
same side)
Two vector magnitudes |A| = 8 units and |B| =5 units make an angle that
cantovary
0° 180°from
. The magnitude of the resultant vector A + B CANNOT have
the value of:
A. 2
units
B. 5
units
, C. 8
units
D. 12 units correct
answersA.
The magnitude of A+B is as small as 3 units and as large as 13 units. The
magnitude
2 of
units is smaller than the smallest possible magnitude of
vector A+B.
What is the effect produced by the PRK technique designed
to correct
nearsightednes
s?
A. The density of the cornea is
increased
B. The radius of curvature of the cornea is
increased
C. The index of refraction of the cornea is
increased
D. The thickness of the cornea at the apex is increased correct
answersB.
According to the passage, to correct nearsightedness, the laser beam is
directed
the onto
central part of the cornea, resulting in a flattening of the cornea. This
means that the
radius of curvature of the cornea is
increased.
What is the magnitude of the electric field in the electrical discharge
producedlaser
excimer in the
tube?
A. 2.0 x 10^6
V/m
B. 4.0 x 10^5
V/m
C. 6.0 x 10^4
V/m
D. 8.0 x 10^3 V/m correct
answersA.
The magnitude of the electric field produced by 8.0 kV across 4.0 mm is
8000
m = 2.0V/ 0.004
x 10^6
V/m.
What is the frequency of the pulses that deliver laser radiation to
the cornea?
A. 0.4
Hz
B. 4.0
Hz
C. 25
Hz
D. 250 Hz correct
answersB.
The frequency is 1/250 ms =
4 Hz
The use of pulsed laser radiation in the PRK procedure, as opposed to
continuousallows
radiation, laser the
cornea to:
A. absorb more
radiation
B. change its index of
refraction
C. increase the area exposed to
radiation
D. maintain a lower average temperature correct
answersD.
