Free Response Review Packet
1. Base your answer to the following question on the information below and on your knowledge of
chemistry.
Illuminated EXIT signs are used in public buildings such as schools. If the word EXIT is
green, the sign may contain the radioisotope tritium, hydrogen-3. The tritium is a gas sealed in
glass tubes. The emissions from the decay of the tritium gas cause a coating on the inside of
the tubes to glow.
State, in terms of neutrons, how an atom of tritium differs from an atom of hydrogen-1.
Base your answers to questions 2 and 3 on
the information below and on your knowledge of chemistry.
A student compares some models of the atom. These models are listed in the table below
in order of development from top to bottom.
2. State one way in which the Bohr model agrees with the Thomson model.
3. Using the conclusion from the Rutherford model, identify the charged subatomic particle that is
located in the nucleus.
Free Response Review Packet
4. Base your answer to the following question on
the information below and on your knowledge of chemistry.
Chemical concepts are applied in candy making. A recipe for making lollipops is shown below.
Hard-Candy Lollipops Recipe
Ingredients:
414 grams of sugar
177 grams of water
158 milliliters of light corn syrup
Step 1: In a saucepan, mix the sugar and water. Heat this mixture, while stirring, until all of the
sugar dissolves.
Step 2: Add the corn syrup and heat the mixture until it boils.
Step 3: Continue boiling the mixture until the temperature reaches 143°C at standards pressure.
Step 4: Remove the pan from the heat and allow it to stand until the bubbling stops. Pour the
mixture into lollipop molds that have been coated with cooking oil spray.
Explain, in terms of the concentration of sugar molecules, why the boiling point of the mixture in
step 3 increases as water evaporates from the mixture.
5. Base your answer to the following question on
the information below and on your knowledge of chemistry.
Two very stable compounds, Freon-12 and Freon-14, are used as liquid refrigerants. A
Freon-12 molecule consists of one carbon atom, two chlorine atoms, and two fluorine atoms. A
Freon-14 molecule consists of one carbon atom and four fluorine atoms.
To which class of organic compounds do Freon-12 and Freon-14 belong?
Free Response Review Packet
6. Base your answer to the following question on the information below.
The bright-line spectra for three elements and a mixture of elements are shown below.
Explain, in terms of both electrons and energy, how the bright-line spectrum of an element is
produced.
7. Copper has two naturally occurring isotopes. Information about the two isotopes is shown in the
table below.
In the space in your answer booklet, show a numerical setup for calculating the atomic mass of
copper.
8. In the box below, draw a Lewis electron-dot diagram for an atom of boron.
Free Response Review Packet
9. Determine the mass number of the magnesium atom represented by the electron-shell diagram.
10. Write one electron configuration for an atom of silicon in an excited state.
11. Base your answer to the following question on
the information below and on your knowledge of chemistry.
There are six elements in Group 14 on the Periodic Table. One of these elements has the
symbol Uuq, which is a temporary, systematic symbol. This element is now known as
flerovium.
Explain, in terms of electron shells, why each successive element in Group 14 has a larger
atomic radius, as the elements are considered in order of increasing atomic number.
12. Explain, in terms of atomic structure, why Group 18 elements on the Periodic Table rarely form
compounds.
13. Explain, in terms of electrons, why the radius of a potassium atom is larger than the radius of a
potassium ion in the ground state.
Free Response Review Packet
14. Base your answer to the following question on the information below and on your knowledge of
chemistry.
Silver-plated utensils were popular before stainless steel became widely used to make eating
utensils. Silver tarnishes when it comes in contact with hydrogen sulfide,
, which is found in
the air and in some foods. However, stainless steel does not tarnish when it comes in contact
with hydrogen sulfide.
Draw a Lewis electron-dot diagram for the compound that tarnishes silver.
15. Base your answer to the following question on
the information below and on your knowledge of chemistry.
The diagram below represents three elements in Group 13 and three elements in Period 3
and their relative positions on the Periodic Table.
Some elements in the solid phase exist in different forms that vary in their physical properties.
For example, at room temperature, red phosphorus has a density of 2.16 g/cm3 and white
phosphorus has a density of 1.823 g/cm3.
Consider the Period 3 elements in the diagram in order of increasing atomic number. State the
trend in electronegativity for these elements.
Free Response Review Packet
16. Base your answer to the following question on
the information below and on your knowledge of chemistry.
Before atomic numbers were known, Mendeleev developed a classification system for the
63 elements known in 1872, using oxide formulas and atomic masses. He used an R in the
oxide formulas to represent any element in each group. The atomic mass was listed in
parentheses after the symbol of each element. A modified version of Mendeleev's
classification system is shown in the table below.
Based on Mendeleev's oxide formula, what is the number of electrons lost by each atom of the
elements in Group III?
17. Base your answer to the following question on the information below.
The atomic radius and the ionic radius for some Group 1 and some Group 17
elements are given in the tables below.
Explain, in terms of electron shells, why the radius of a K + ion is greater than the radius of an Na
+ ion.
Free Response Review Packet
Base your answers to questions 18 through 21 on
the information below.
Two sources of copper are cuprite, which has the IUPAC name copper(I) oxide, and malachite,
which has the formula Cu 2 CO 3 (OH) 2 . Copper is used in home wiring and electric motors
because it has good electrical conductivity. Other uses of copper not related to its electrical
conductivity include coins, plumbing, roofing, and cooking pans.Aluminum is also used for
cooking pans.
At room temperature, the electrical conductivity of a copper wire is 1.6 times greater than an
aluminum wire with the same length and cross-sectional area. At room temperature, the heat
conductivity of copper is 1.8 times greater than the heat conductivity of aluminum. At STP, the
density of copper is 3.3 times greater than the density of aluminum.
18. Identify one physical property of aluminum that could make it a better choice than copper for a
cooking pan.
19. Identify one physical property of copper that makes it a good choice for uses that are not related
to electrical conductivity.
20. Determine the oxidation number of oxygen in the carbonate ion found in malachite.
21. Write the chemical formula of cuprite.
22. Explain, in terms of electron configuration, why selenium and sulfur have similar chemical
properties.
Free Response Review Packet
Base your answers to questions 23 through 25 on
the information below and on your knowledge of chemistry.
The formulas and the boiling points at standard pressure for ethane, methane, methanol,
and water are shown in the table below.
23. Explain, in terms of molecular polarity, why the solubility of methanol in water is greater than the
solubility of methane in water.
24. State the change in potential energy that takes place in a sample of methane as it boils at
–161.5°C.
25. Identify the compound that has the strongest intermolecular forces.
Free Response Review Packet
26. Base your answer to the following question on
the information below and on your knowledge of chemistry.
A 1.00-mole sample of glucose,
by the balanced equation below.
, completely reacts with oxygen, as represented
Using the axes above, complete the potential energy curve for the reaction of glucose with
oxygen.
27. Base your answer to the following question on the information below and on your knowledge of
chemistry.
Rubbing alcohol is a product available at most pharmacies and supermarkets. One rubbing
alcohol solution contains 2-propanol and water. The boiling point of 2-propanol is 82.3°C at
standard pressure.
Explain in terms of electronegativity differences, why a C–O bond is more polar than a C–H
bond.
28. Base your answer to the following question on
the information below.
Ammonium chloride is dissolved in water to form a 0.10 M NH 4 Cl(aq) solution. This dissolving
process is represented by the equation below.
Determine the minimum mass of NH 4 Cl(s) required to produce a saturated solution in 100.
grams of water at 40.°C.
Free Response Review Packet
Base your answers to questions 29 and 30 on the information below.
In 1864, the Solvay process was developed to make soda ash. One step in the process is
represented by the balanced equation below.
NaCl + NH 3 + CO 2 + H2O ®NaHCO 3 + NH 4 Cl
29. In the space draw a Lewis electron-dot diagram for the reactant containing nitrogen in the
equation.
30. Write the chemical formula for one compound in the equation that contains both ionic bonds and
covalent bonds.
31. Base your answer to the following question on the information below.
Carbon has three naturally occurring isotopes, C-12, C-13, and C-14. Diamond and
graphite are familiar forms of solid carbon. Diamond is one of the hardest substances known,
while graphite is a very soft substance. Diamond has a rigid network of bonded atoms.
Graphite has atoms bonded in thin layers that are held together by weak forces.
Recent experiments have produced new forms of solid carbon called fullerenes. One
fullerene, C60, is a spherical, cagelike molecule of carbon.
State, in terms of the arrangement of atoms, the difference in hardness between diamond and
graphite.
Free Response Review Packet
32. Base your answer to the following question on the information below.
Explain why Lewis electron-dot diagrams are generally more suitable than electron-shell
diagrams for illustrating chemical bonding.
Base your answers to questions 33 through 36 on
the table below.
33. Explain, in terms of molecular polarity, why hydrogen chloride is more soluble than hydrogen in
water under the same conditions of temperature and pressure.
Free Response Review Packet
34. Explain, in terms of intermolecular forces, why hydrogen has a lower boiling point than hydrogen
bromide.
35. The density of hydrogen at STP is 0.0899 gram per liter. Express this density to two significant
figures.
36. The volume of 1.00 mole of hydrogen bromide at STP is 22.4 liters. The gram-formula mass of
hydrogen bromide is 80.9 grams per mole. What is the density of hydrogen bromide at STP?
Base your answers to questions 37 and 38 on
the information below and on your knowledge of chemistry.
The diagram below represents a cylinder with a movable piston. The cylinder contains 1.0
liter of oxygen gas at STP. The movable piston in the cylinder is pushed downward at
constant temperature until the volume of 0 2(g) is 0.50 liter.
37. State the effect on the frequency of gas molecule collisions when the movable piston is pushed
farther downward into the cylinder.
38. Determine the new pressure of O 2 (g) in the cylinder, in atmospheres.
Base your answers to questions 39 and 40 on
the information below and on your knowledge of chemistry.
A few pieces of dry ice,
, at
are placed in a flask that contains air at
.
The flask is sealed by placing an uninflated balloon over the mouth of the flask. As the balloon
inflates, the dry ice disappears and no liquid is observed in the flask.
39. Write the name of the process that occurs as the dry ice undergoes a phase change in the flask.
40. State the direction of heat flow that occurs between the dry ice and the air in the flask.
Free Response Review Packet
41. Base your answer to the following question on the information below and on your knowledge of
chemistry.
Paintball is a popular recreational activity that uses a metal tank of compressed carbon
dioxide or nitrogen to launch small capsules of paint. A typical tank has a volume of 508 cubic
centimeters. A 340.-gram sample of carbon dioxide is added to the tank before it is used for
paintball. At 20.°C, this tank contains both CO 2(g) and CO2( ). After a paintball game, the
tank contains only CO2(g).
In the box above, use the key to draw a particle diagram to represent the two phases of CO 2 in a
newly filled tank. Your response must include at least six molecules of CO 2 in each phase.
Base your answers to questions 42 and 43 on
the information below.
A student investigated heat transfer using a bottle of water. The student placed the bottle in a
room at 20.5°C. The student measured the temperature of the water in the bottle at 7 a.m. and
again at 3 p.m. The data from the investigation are shown in the table below.
42. Show a numerical setup for calculating the change in the thermal energy of the water in the
bottle from 7 a.m. to 3 p.m.
43. State the direction of heat transfer between the surroundings and the water in the bottle from 7
a.m. to 3 p.m.
Free Response Review Packet
Base your answers to questions 44 and 45 on the information below.
Starting as a gas at 206°C, a sample of a substance is allowed to cool for 16
minutes. This process is represented by the cooling curve below.
44. Using the key below, draw two particle diagrams to represent the two phases of the sample at
minute 4. Your response must include at least six particles for each diagram.
45. At what time do the particles of this sample have the lowest average kinetic energy?
Free Response Review Packet
46. Base your answer to the following question on
Heat is added to a sample of liquid water, starting at 80.ºC, until the entire sample is a
gas at 120.ºC. This process, occurring at standard pressure, is represented by the balanced
equation below.
H 2 O( ) + heat ® H 2 O(g)
On the diagram below, complete the heating curve for this physical change.
47. A liquid boils when the vapor pressure of the liquid equals the atmospheric pressure on the
surface of the liquid. Using Reference Table H, determine the boiling point of water when the
atmospheric pressure is 90. kPa.
48. Base your answer to the following question on
the information below and on your knowledge of chemistry.
Many breads are made by adding yeast to dough, causing the dough to rise. Yeast is a
type of microorganism that produces the catalyst zymase, which converts glucose,
,
to ethanol and carbon dioxide gas. The balanced equation for this reaction is shown below.
Describe how the catalyst, zymase, speeds up this reaction.
49. Base your answer to the following question on the information below and on your knowledge of
chemistry.
The compounds
and
are soluble in water.
Compare the entropy of 30. grams of solid
at 20.°C with the entropy of 30. grams of
dissolved in 100. grams of water at 20.°C.
Free Response Review Packet
Base your answers to questions 50 and 51 on the information below.
The chemical reaction between methane and oxygen is represented by the potential energy
diagram and balanced equation below.
50. Explain, in terms of collision theory, why a lower concentration of oxygen gas decreases the rate
of this reaction.
51. Which potential energy interval in the diagram represents the activation energy of the
forward reaction?
52. Base your answer to the following question on
Propane is a fuel that is sold in rigid, pressurized cylinders. Most of the propane in a
cylinder is liquid, with gas in the space above the liquid level. When propane is released from
the cylinder, the propane leaves the cylinder as a gas. Propane gas is
C3H8(g) + 5O 2(g) 2CO2(g) + 4H2O( ) + 2219.2kJ
A small amount of methanethiol, which has a distinct odor, is added to the propane to help
consumers detect a propane leak. In methanethiol, the odor is caused by the thiol functional
group (–SH). Methanethiol, CH3SH, has a structure that is very similar to the structure of
methanol.
Draw a particle diagram to represent propane in a pressurized cylinder. Your response must
include at least six molecules of propane in the gas phase and at least six molecules of propane
in the liquid phase.
Free Response Review Packet
53. Explain, in terms of collision theory, why the rate of a chemical reaction increases with an
increase in temperature.
54. A potential energy diagram for a chemical reaction is shown below. On this diagram, draw a
curve to show how the potential energy diagram will change when a catalyst is added to the
reaction.
Base your answers to questions 55 and 56 on the information below.
A method used by ancient Egyptians to obtain copper metal from copper(I) sulfide ore was
heating the ore in the presence of air. Later, copper was mixed with tin to produce a useful alloy
called bronze.
55. Convert the melting point of the metal obtained from copper(I) sulfide ore to degrees Celsius.
56. Calculate the density of a
-gram sample of bronze that has a volume of
cubic
centimeters. Your response must include a correct numerical setup and the calculated result.
57. Based on data collected during a laboratory investigation, a student determined an experimental
value of 322 joules per gram for the heat of fusion of H 2 O. Calculate the student's percent error.
Your response must include a correct numerical setup and the calculated result.
Free Response Review Packet
Base your answers to questions 58 and 59 on
the information below.
A student performed an experiment to determine the total amount of energy stored in a peanut.
The accepted value for the energy content of a peanut is 30.2 kilojoules per gram. The student
measured 100.0 grams of water into a metal can and placed the can on a ring stand, as shown in
the diagram below. The peanut was attached to a wire suspended under the can.
The initial temperature of the water was recorded as 22.0° C. The peanut was ignited and
allowed to burn. When the peanut finished burning, the final water temperature was recorded as
57.0° C. The student's experimental value for the energy content of this peanut was 25.9
kilojoules per gram.
58. Determine the student’s percent error for the energy content of this peanut.
59. Calculate the total amount of heat absorbed by the water. Your response must include both a
correct numerical setup and the calculated result.
Answer Key
Quarter II Review
1.
2.
–A tritium atom has
two neutrons and an
H-1 atom has no
neutrons. –Only the
tritium atom has
neutrons. –H-1 has no
neutrons.
7.
3.
–proton –p –p+ – 11p –
11.
1 1 H –H +
4.
–The boiling point of
the mixture increases
as water evaporates
because the
concentration of
dissolved molecules
increases. –An
increase in the
concentration of sugar 12.
particles increases the
boiling point.
–halide –halocarbon
6.
– When electrons in
an excited state return
to a lower energy
state, specific amounts
of energy are emitted.
These energies are
associated with
specific wavelengths
of light that are
characteristic of the
bright-line spectrum
of an element. –
Energy is emitted
when excited
electrons fall back to
lower shells.
13.
8.
–Atoms have
electrons. –Atoms
have small, negatively
charged particles.
9.
–Both models show
10.
an internal structure.
–Atoms are neutral.
5.
Acceptable responses
include, but are not
limited to: • (62.93
u)(0.6917) + (64.93
u)(0.3083) or
23
Examples: - 2–7–4–1 ;
2–7–5 ; 2–8–3–1
;1–8–5
–The atomic radius of
these elements
increases down the
group because each
successive element
has one more electron
shell. –The number of
shells per atom
increases.
–A potassium atom
has four electron
shells and a potassium
ion has three electron
shells. –A potassium
atom has one more
electron shell than a
potassium ion. –A K +
ion has one fewer
electron than a K
atom.
19.
Copper is very
malleable or a good
conductor of heat or a
high melting point
20.
–2
21.
Cu2O
22.
Examples: – An atom
of each element has
six electrons in its
outer shell. – same
number of valence
electrons
23.
–Methanol and water
molecules are polar,
but methane molecule
are nonpolar. –The
compounds methanol
and water have similar
polarities.
24.
–As liquid methane
boils, the potential
energy of the sample
increases. –Potential
energy increases.
–higher PE
25.
H2O/water
14.
15.
Group 18 elements
rarely form
compounds because
their atoms have
stable electron
configurations. –Their 16.
valence shells are
completely filled. –All
17.
the elements have
maximum numbers of
valence electrons.
–Atoms of Group 18
have a stable octet
except He, which is
stable with two
electrons.
18.
– As atomic number
increases, the
electronegativity
increases. –
Electronegativity
increases. – from
lower to higher
–three electrons –three
–3
—A K + ion has
three electron shells
and an Na+ ion has
only two. —A
sodium ion has fewer
electron shells than a
potassium ion.
–An aluminum pan
has less mass than a
copper pan of the
same size because
aluminum is less
dense. –Aluminum is
less dense than
copper. –A Cu pan
would weigh more.
26.
Answer Key
Quarter II Review
27.
28.
– There is a greater
electronegativity
difference in a CO
bond than in a CH
bond. – The CO bond
is more polar because
the electronegativity
difference for a CO
bond is 0.8, and the
electronegativity
difference for a CH
bond is 0.4. – The CH
bond has a smaller
difference. – The CO
is .8 and the CH is .4
47 g
33.
34.
1 g.
29.
35.
0.090 g/L or 9.0 × 10
–2 g/L
36.
3.61 g/L
37.
30.
NaHCO 3 or NH 4Cl.
31.
Diamond has atoms
bonded strongly in a
three-dimensional
network. Graphite has
atoms that are held
weakly between
layers.
32.
Lewis electron-dot
diagrams only show
valence electrons,
which are involved in
bonding.
Examples: – HCl's
43.
molecular polarity is
more similar to
water's polarity than H
2 's polarity compared
to water's – HCl and
water both polar, H 2
44.
nonpolar, like
dissolves like – HCl
polarity is more
similar to water's
polarity
45.
Examples: –
Hydrogen has weaker 46.
intermolecular forces
than HBr. – hydrogen
– weaker forces.
38.
47.
–When the piston is
moved farther into the 48.
cylinder, the
frequency of collision
between the molecules
increases. –There will
be more collisions per
second. –increased
frequency
49.
2 atm/2.0 atm
39.
–sublimation
–subliming
40.
–Heat flows from the
air in the flask to the
dry ice. –air to
–to dry ice –from air
41.
42.
–Heat was transferred 52.
from the surroundings
to the water in the
bottle. –The water
absorbed energy from
the surroundings.
53.
minute 16 or at 16
minutes
a line is drawn
horizontally to
54.
represent the phase
change and extending
the line with a positive
slope to represent the
gas phase, only.
97°C ± 1°C.
55.
–Zymase is a catalyst
56.
that provides an
alternative pathway,
which requires less
energy. –decreases the 57.
activation energy
–changes the reaction
mechanism
– The entropy of
is less than 58.
the entropy of
59.
. – The
is more
disordered. – The
solution is more
random the solid.
50.
Acceptable responses
include, but are not
limited to: • A lower
concentration of
oxygen gas decreases
the number of
effective collisions
between O2 molecules
and CH 4 molecules.
51.
B
q = (800. g)(4.18 J/g •
ºC)(20.5ºC – 12.5ºC)
(800)(4.18)(8)
As temperature
increases, the rate of a
chemical reaction
increases because the
reactant particles
move faster and
collide more often.
Answer: 1084ºC
332 J/g – 334 J/g ×
100
334 J/g
Examples: –3.6%; 4%
-14% or 14%.