AP CHEM FULL MIDTERM REVIEW
(UNITS 1-6)|| (LATEST )
QUESTIONS WITH REVISED ANSWERS,
(A+ GUARANTEE)
A solution is prepared by adding 16.0 g of CH OH to 90.0 g of H2O. The mole fraction of
CH OH in this solution is closest to which of the following?
a, 0.1
b. 0.2
c. 0.3
d 0.4 - correct answers b. 0.2
In 1.00 mol of potassium zirconium sulfate trihydrate, KaZr(SO4)4 • 3 H2O, there are a
1.81 x 1024 hydrogen atoms
b. 6.02 × 1023 sulfur atoms
c. 2.41 x 1024 potassium atoms
d. 4 moles of oxygen atoms
e. 4 moles of zirconium atoms - correct answers c. 2.41 x 1024 potassium atoms
A student has a 1.0 g sample of each of the following compounds: NaCI, KBr, and KCL
Which of the following lists the samples in order of increasing number of moles in the
sample?
a. NaCI < KCI < KBr
b. NaCI < KBr < KCI
c. KCI < NaCI < KBr
d. KBr < KCI < NaCI - correct answers a. NaCI < KCI < KBr
A student obtains a sample of a pure solid compound. In addition to Avogadro's
number, which of the following must the student know in order to determine how many
molecules are in the sample?
a. Mass of the sample, volume of the sample
b. Mass of the sample, density of the sample
c. Molar mass of the compound, mass of the sample
,d. Molar mass of the compound, density of the sample - correct answers C. Molar mass
of the compound, mass of the sample
According to the information in the table at right, a 1.00 g sample of which of the
following contains the greatest mass of oxygen?
a. Na.O
b. MgO
c. K20
d. CaO - correct answers b. MgO
What differentiates a homogeneous mixture from a pure substance?
a. The composition of a pure substance is fixed
b. A pure substance can be separated into elements by physical means
c. A pure substance is always a compound while mixtures can be elements or
compounds
d. A homogeneous mixture is uniform throughout - correct answers a. The composition
of a pure substance is fixed
A student is given two 10 g samples, each a mixture of only NaC(sand Cs) but in
different proportions. Which of the following pieces of information could be used to
determine which mixture has the higher proportion of KCI(s)?
a. The volume o each mixure
b. The mass of Cl in each mixture
c. The number of isotopes of Na and K
d. The reaction or each mixture with water - correct answers b. The mass of Cl in each
mixture
An experiment is performed to measure the mass percent of CaCOs(s) in eggshells.
Five different samples of CaCOss) of known mass react with an excess of 2.0 M HClag)
in identical sealed, rigid reaction vessels. The
pressure of he gas proouceds measured win a pressure gauge atached o me reaction
vessel, since me
reactions exoteric me reaction system is cooleo to ns onginartemperature before te
pressure is recorded
The experimental dala are used to creale tre Caloraton Iine befou 5 Ca Coz + 2.0M
HCkag)
The experiment is repeated with an eggshell sample, and the experimental data are
recorded in the table below.
The mass percent of CaCOss) in the eggshell sample is closest to
a. 30%
b. 45%
c. 60%
d. 75% - correct answers d. 75%
, The percentage of silver in a solid sample is determined gravimetrically by converting
the silver to Ag aq) and precipitating it as silver chlonde. Failure to do which of the
following could cause errors in the analysis?
I Account for the mass of the weighing paper when the mass of the sample
II Measure the temperaure during the preciptation reaction
III wash me precipitate
IV Heat the AgCI precipitate to constant mass
a. I only
b. I and Il
c. I and IV
d. I and III
e. I, III and IV - correct answers e. I, III and IV
A 5.0 g sample of MgCl2 may contain measurable amounts of other compounds as
impurities. Which of the following quantities is (are) needed to determine that the
sample is pure MgCI2?
a. The color and density of the sample
b. The mass of Mg in the sample only
c. The number of moles of Cl in the sample only
d. The mass of Mg and the mass or clin the sample - correct answers d. The mass of
Mg and the mass of Cl the sample
To gravimetrically analyze the silver content of a piece of jewelry made from an alloy of
Ag and Cu, a student dissolves a small pre-weighed sample in HNO3(ag). Ag*(ag) and
Cu?*(ag) ions form in the solution. Which of the following should be the next step in the
analytical process?
a. Centrifuging the solution to isolate the heavier ions
b. Evaporating the solution to recover the dissolved nitrates
c. Adding enough base solution to bring the pH up to 7.0
d. Adding a solution containing an anion that forms an insoluble salt with only one of the
metal ions - correct answers d. Adding a solution containing an anion that forms an
insoluble salt with only one of the metal ions
The mass percent of carbon in pure glucose, C6H1206, is 40.0 %. A chemist analyzes
an impure sample of glucose and determines that the mass percent of carbon is 38.2%.
Which of the following impurities could account for the low mass percent of carbon in
the sample?
a. Water, H20
b. Fructose, C6H1206, isomer of glucose
c. Ribose, C5H1005
d. Sucrose, C12H22011 - correct answers a. Water, H20
sample of a solid labeled as NaCI may be impure. A student analyzes the sample and
determines that it contains 75 percent chlorine by mass. Pure NaCI(s) contains 61
percent chlorine by mass. Which of the following statements is consistent with the data?
, a. The sample contains only NaCI(s)
b. The sample contains NaCI(s) and Nals)
c. The sample contains NaCI(s) and KCI(s)
d. The sample contains NaCI(s) and LiCI(s) - correct answers d. The sample contains
NaCI(s) and LiCI(s)
The atom that contains exactly two unpaired electrons
a. S
b. Ca
c. Ga
d. Sb
e. Br - correct answers a. S
Which of the following ground-state electron configurations represents the atom that
has the lowest first-ionization energy?
a. 152251
b. 1522522p2
c. 15?252206
d. 1s22s22p63s' - correct answers d. 1s22s22p63s' , most electrons
Which of the following is the ground-state electron configurations of the fluoride ion?
a. 1s2s522p
b. 1s?2s22p5
c. 1s2s22p6
d. 1s?2572p63s?3p - correct answers c. 1s2s22p6
Which of the following best represents the ground-state electron configuration for an
atom of selenium?
a. 1s?2s 2p63s?3p3
b. 1s?25?2p3s?3p
c. 15?2s22p63523p4s3d104p4
d. 1s?2s2p63s23p64s23d104p5 - correct answers c. 15?2522p63523p4s3d104p4
The effective nuclear charge experienced by the outermost electron of Na is different
than the effective nuclear charge experienced by the outermost electron of Ne. This
difference best accounts for which of the following?
a. Na has a greater density at standard conditions than Ne.
b. Na has a lower first ionization energy than Ne.
c. Na has a higher melting point than Ne
d. Na has a higher neutron-to-proton ratio than Ne.
e. Na has fewer naturally occurring isotopes than Ne. - correct answers b. Na has a
lower first ionization energy than Ne.
Which of the following is the electron configuration of an excited atom that is likely to
emit a quantum of energy?
a. 1s?2522p63s?3p1
(UNITS 1-6)|| (LATEST )
QUESTIONS WITH REVISED ANSWERS,
(A+ GUARANTEE)
A solution is prepared by adding 16.0 g of CH OH to 90.0 g of H2O. The mole fraction of
CH OH in this solution is closest to which of the following?
a, 0.1
b. 0.2
c. 0.3
d 0.4 - correct answers b. 0.2
In 1.00 mol of potassium zirconium sulfate trihydrate, KaZr(SO4)4 • 3 H2O, there are a
1.81 x 1024 hydrogen atoms
b. 6.02 × 1023 sulfur atoms
c. 2.41 x 1024 potassium atoms
d. 4 moles of oxygen atoms
e. 4 moles of zirconium atoms - correct answers c. 2.41 x 1024 potassium atoms
A student has a 1.0 g sample of each of the following compounds: NaCI, KBr, and KCL
Which of the following lists the samples in order of increasing number of moles in the
sample?
a. NaCI < KCI < KBr
b. NaCI < KBr < KCI
c. KCI < NaCI < KBr
d. KBr < KCI < NaCI - correct answers a. NaCI < KCI < KBr
A student obtains a sample of a pure solid compound. In addition to Avogadro's
number, which of the following must the student know in order to determine how many
molecules are in the sample?
a. Mass of the sample, volume of the sample
b. Mass of the sample, density of the sample
c. Molar mass of the compound, mass of the sample
,d. Molar mass of the compound, density of the sample - correct answers C. Molar mass
of the compound, mass of the sample
According to the information in the table at right, a 1.00 g sample of which of the
following contains the greatest mass of oxygen?
a. Na.O
b. MgO
c. K20
d. CaO - correct answers b. MgO
What differentiates a homogeneous mixture from a pure substance?
a. The composition of a pure substance is fixed
b. A pure substance can be separated into elements by physical means
c. A pure substance is always a compound while mixtures can be elements or
compounds
d. A homogeneous mixture is uniform throughout - correct answers a. The composition
of a pure substance is fixed
A student is given two 10 g samples, each a mixture of only NaC(sand Cs) but in
different proportions. Which of the following pieces of information could be used to
determine which mixture has the higher proportion of KCI(s)?
a. The volume o each mixure
b. The mass of Cl in each mixture
c. The number of isotopes of Na and K
d. The reaction or each mixture with water - correct answers b. The mass of Cl in each
mixture
An experiment is performed to measure the mass percent of CaCOs(s) in eggshells.
Five different samples of CaCOss) of known mass react with an excess of 2.0 M HClag)
in identical sealed, rigid reaction vessels. The
pressure of he gas proouceds measured win a pressure gauge atached o me reaction
vessel, since me
reactions exoteric me reaction system is cooleo to ns onginartemperature before te
pressure is recorded
The experimental dala are used to creale tre Caloraton Iine befou 5 Ca Coz + 2.0M
HCkag)
The experiment is repeated with an eggshell sample, and the experimental data are
recorded in the table below.
The mass percent of CaCOss) in the eggshell sample is closest to
a. 30%
b. 45%
c. 60%
d. 75% - correct answers d. 75%
, The percentage of silver in a solid sample is determined gravimetrically by converting
the silver to Ag aq) and precipitating it as silver chlonde. Failure to do which of the
following could cause errors in the analysis?
I Account for the mass of the weighing paper when the mass of the sample
II Measure the temperaure during the preciptation reaction
III wash me precipitate
IV Heat the AgCI precipitate to constant mass
a. I only
b. I and Il
c. I and IV
d. I and III
e. I, III and IV - correct answers e. I, III and IV
A 5.0 g sample of MgCl2 may contain measurable amounts of other compounds as
impurities. Which of the following quantities is (are) needed to determine that the
sample is pure MgCI2?
a. The color and density of the sample
b. The mass of Mg in the sample only
c. The number of moles of Cl in the sample only
d. The mass of Mg and the mass or clin the sample - correct answers d. The mass of
Mg and the mass of Cl the sample
To gravimetrically analyze the silver content of a piece of jewelry made from an alloy of
Ag and Cu, a student dissolves a small pre-weighed sample in HNO3(ag). Ag*(ag) and
Cu?*(ag) ions form in the solution. Which of the following should be the next step in the
analytical process?
a. Centrifuging the solution to isolate the heavier ions
b. Evaporating the solution to recover the dissolved nitrates
c. Adding enough base solution to bring the pH up to 7.0
d. Adding a solution containing an anion that forms an insoluble salt with only one of the
metal ions - correct answers d. Adding a solution containing an anion that forms an
insoluble salt with only one of the metal ions
The mass percent of carbon in pure glucose, C6H1206, is 40.0 %. A chemist analyzes
an impure sample of glucose and determines that the mass percent of carbon is 38.2%.
Which of the following impurities could account for the low mass percent of carbon in
the sample?
a. Water, H20
b. Fructose, C6H1206, isomer of glucose
c. Ribose, C5H1005
d. Sucrose, C12H22011 - correct answers a. Water, H20
sample of a solid labeled as NaCI may be impure. A student analyzes the sample and
determines that it contains 75 percent chlorine by mass. Pure NaCI(s) contains 61
percent chlorine by mass. Which of the following statements is consistent with the data?
, a. The sample contains only NaCI(s)
b. The sample contains NaCI(s) and Nals)
c. The sample contains NaCI(s) and KCI(s)
d. The sample contains NaCI(s) and LiCI(s) - correct answers d. The sample contains
NaCI(s) and LiCI(s)
The atom that contains exactly two unpaired electrons
a. S
b. Ca
c. Ga
d. Sb
e. Br - correct answers a. S
Which of the following ground-state electron configurations represents the atom that
has the lowest first-ionization energy?
a. 152251
b. 1522522p2
c. 15?252206
d. 1s22s22p63s' - correct answers d. 1s22s22p63s' , most electrons
Which of the following is the ground-state electron configurations of the fluoride ion?
a. 1s2s522p
b. 1s?2s22p5
c. 1s2s22p6
d. 1s?2572p63s?3p - correct answers c. 1s2s22p6
Which of the following best represents the ground-state electron configuration for an
atom of selenium?
a. 1s?2s 2p63s?3p3
b. 1s?25?2p3s?3p
c. 15?2s22p63523p4s3d104p4
d. 1s?2s2p63s23p64s23d104p5 - correct answers c. 15?2522p63523p4s3d104p4
The effective nuclear charge experienced by the outermost electron of Na is different
than the effective nuclear charge experienced by the outermost electron of Ne. This
difference best accounts for which of the following?
a. Na has a greater density at standard conditions than Ne.
b. Na has a lower first ionization energy than Ne.
c. Na has a higher melting point than Ne
d. Na has a higher neutron-to-proton ratio than Ne.
e. Na has fewer naturally occurring isotopes than Ne. - correct answers b. Na has a
lower first ionization energy than Ne.
Which of the following is the electron configuration of an excited atom that is likely to
emit a quantum of energy?
a. 1s?2522p63s?3p1
