Chemistry 300
Midterm Review 2015
ONLY MATTER, ATOMIC STRUCTURE, NUCLEAR, and PT UNITS
Make sure that you can solve problems like the ones shown here. Please remember, this should
NOT be your only way of studying. Make sure to study your notes, quizzes, and tests. It is
important to make your mind active when you study… simply “reviewing notes” and “looking
over problems” DOES NOT WORK. Quiz yourself. Quiz each other. Do practice problems.
Redo old problems under test taking conditions (i.e., with no notes) and analyze how you did and
what you need to work on. Also… this page does not leave space for your work… so plan on
doing these on separate paper or in your notebook.
There are TWO types of Questions Below: Fill-in and Multiple Choice
MATTER
1. What is the difference between all of the following: pure substance, mixture, element,
compound, homogeneous mixture, heterogeneous mixture, solution, suspension? How
are these terms related to each other?
2. Which words from #1 could be used to classify the following: carbon, aqueous
copper(II)chloride, muddy water, sulfur dioxide, blood, potassium permanganate crystals,
chicken soup, and titanium?
3. What are some ways to separate mixtures? How about pure substances?
4. What is the difference between physical and chemical properties of matter? List a few
examples for each type.
5. What is the difference between a physical change and a chemical change? List a few
examples of each type of change.
6. List some signs to indicate that a chemical change or chemical reaction has taken place.
ATOMIC STRUCTURE and Basics of the PERIODIC TABLE
7. Describe the contributions of Dalton, Thomson, Rutherford, and Bohr to our “picture” of
the structure of the atom.
8. What is the key difference between Bohr’s idea of atomic structure from the quantum
mechanical model?
9. What does atomic number represent? How do you recognize it on any Periodic Table?
Give an example of an element and its atomic number.
10. What does atomic mass represent? How do you recognize it on any Periodic Table?
Give an example of an element and its atomic mass.
11. How is the atomic mass of an element determined?
12. What does mass number represent? How is it determined? Give an example of an
element and its mass number.
13. What is an isotope? How many protons, neutrons, and electrons are in an isotope of
carbon with a mass number of 14? How about in potassium-40?
14. What is an ion? Why do ions form?
15. What is the difference between a cation and anion? What kind of elements tend to form
cations? How do they do it? What kind of elements tend to form anions? How do they
do it?
16. How many protons, neutrons, and electrons are in an ion of rubidium? How about in an
ion of bromine?
17. What does it mean if something is isoelectronic? What element are the ions in #28
isoelectronic with?
NUCLEAR CHEMISTRY
18. What are some of the benefits and dangers of nuclear radiation?
19. What does the concept of half life mean?
20. If isotope Z has a half life of 20 days… if we start out with 100 g of isotope Z, how much
would be left after 80 days? What fraction of the original amount would be remaining at
that point?
21. If we have the same isotope as in #37… this time, we have 15 g remaining after 120 days.
What was the original amount?
22. What is the difference between fission and Fusion ?
23. How do Fission reactors produce electricity ?
NUCLEAR CHEMISTRY REVIEW
TRY QUESTIONS 1-18 below. CHECK THE ANSWER AND READ THE
EXPLANATION EVEN IF YOU GOT THE QUESTION CORRECT. When you are
finished, try the next set and check your answers.(answers only, no explanations)
Nuclear Chemistry: Question 1 of 18
This question may require the use of the Chemistry Reference Tables or the Periodic
Table of Elements.
The temperature levels in a nuclear reactor are maintained primarily by the use of
1.
2.
3.
4.
shielding
coolants
moderators
control rods
Correct Answer Number: 2
Explanation: Because heat flows from warm objects to colder objects, the coolant
liquid is used to absorb heat generated by the reactor. The coolant prevents
temperatures in the reactor from overheating (meltdown). The coolant liquid carries
the unused heat to an outside cooling tower--there is a large cooling tower at Nine
Mile 2. Some of the heat will be sent to a boiler to generate steam and turn the
turbines that generate electricity. Shielding prevents radiation leaks; moderators slow
down nuclear reactions; control rods absorb neutrons and halt the reaction.Hint:
When you have are sick and have a temperature, you need to cool down.
More Information
Nuclear Chemistry: Question 2 of 18
This question may require the use of the Chemistry Reference Tables or the Periodic
Table of Elements.
Which radioactive emanations have a charge of -1?
1.
2.
3.
4.
neutrons
gamma rays
alpha particles
beta particles
Correct Answer Number: 4
Explanation: See Reference Table O.
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Nuclear Chemistry: Question 3 of 18
This question may require the use of the Chemistry Reference Tables or the Periodic
Table of Elements.
As the temperature of a sample of a radioactive element decreases, the half-life will
1. decrease
2. increase
3. remain the same
4.
Correct Answer Number: 3
Explanation: Half-life depends on time. Factors like temperature, pressure, and
volume have no effect.
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Nuclear Chemistry: Question 4 of 18
This question may require the use of the Chemistry Reference Tables or the Periodic
Table of Elements.
Which sample will decay least over a period of 30 days? [Refer to Reference Table
N]
1.
2.
3.
4.
10 g of Au-198
10 g of I-131
10 g of P-32
10 g of Rn-222
Correct Answer Number: 3
Explanation: The substance with the longest half-life, P-32 in this problem, will
decay the least in 30 days.
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Nuclear Chemistry: Question 5 of 18
This question may require the use of the Chemistry Reference Tables or the Periodic
Table of Elements.
What kind of radiation will travel through an electric field on a pathway that remains
unaffected by the field?
1.
2.
3.
4.
a proton
a gamma ray
an electron
an alpha particle
Correct Answer Number: 2
Explanation: Particles with charges will be deflected. The only kind of radiation
given that has no charge is a gamma ray. It is pure energy and therefore without
charge.
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Nuclear Chemistry: Question 6 of 18
This question may require the use of the Chemistry Reference Tables or the Periodic
Table of Elements.
Which radioactive isotope is used in geological dating?
1.
2.
3.
4.
uranium-238
iodine-131
cobalt-60
technetium-99
Correct Answer Number: 1
Explanation: Use Reference Table N. Geological dating covers thousands of years.
Only isotopes with long half-lives can be used. The isotope with the longest half-life
is uranium-238. Uranium 238 can be used to date rocks, fossils, and meteorites.
Carbon-14 is used to date matter that was once alive .
Nuclear Chemistry: Question 7 of 18
This question may require the use of the Chemistry Reference Tables or the Periodic
Table of Elements.
Which particle cannot be accelerated in a magnetic field?
1.
2.
3.
4.
alpha particle
beta particle
neutron
proton
Correct Answer Number: 3
Explanation: Only charged particles can be accelerated in a magnetic field. A
neutron does not have a charge. See also #5, this topic.
Nuclear Chemistry: Question 8 of 18
This question may require the use of the Chemistry Reference Tables or the Periodic
Table of Elements.
In a fusion reaction, reacting nuclei must collide. Collisions between two nuclei are
difficult to achieve because the nuclei are
1.
2.
3.
4.
both negatively charged and repel each other
both positively charged and repel each other
oppositely charged and attract each other
oppositely charged and repel each other
Correct Answer Number: 2
Explanation: In fusion light nuclei like hydrogen (deuterium) join to form heavier
nuclei like helium. Because these nuclei are positively charged, they repel each other.
Hint: law of charges states like charges repel and unlike charges attract.
Nuclear Chemistry: Question 9 of 18
This question may require the use of the Chemistry Reference Tables or the Periodic
Table of Elements.
A particle accelerator can increase the kinetic energy of
1.
2.
3.
4.
an alpha particle and a beta particle
an alpha particle and a neutron
a gamma ray and a beta particle
a neutron and a gamma ray
Correct Answer Number: 1
Explanation: Gamma rays are pure energy so you can eliminate answers 3 and 4.
Only charged particles can have their kinetic energy increased in a particle
accelerator. (Electric and magnetic fields are used to speed up the particles and these
field have no effect on uncharged particles). Neutrons have no charge so only alpha
particles and beta particles will be affected. See also #3, this topic.
Nuclear Chemistry: Question 10 of 18
This question may require the use of the Chemistry Reference Tables or the Periodic
Table of Elements.
Which nuclide is a radioisotope used in the study of organic reaction mechanisms?
1.
2.
3.
4.
carbon-12
carbon-14
uranium-235
uranium-238
Correct Answer Number: 2
Explanation: Carbon is found in all organic compounds so eliminate answers 3 and
4. Which isotope of carbon is radioactive? Carbon-14. Carbon-14 is also used to date
fossils. See also #2, this topic.
Nuclear Chemistry: Question 11 of 18
This question may require the use of the Chemistry Reference Tables or the Periodic
Table of Elements.
To make nuclear fission more efficient, which device is used in a nuclear reactor to
slow the speed of neutrons?
1.
2.
3.
4.
internal shield
external shield
control rod
moderator
Correct Answer Number: 4
Explanation: Neutrons can be quickly slowed down by colliding with particles such
as graphite, heavy water (deuterium oxide), and water. These substances keep the
reaction from getting out of control much like a moderator keeps both sides from
getting into an argument or fight. (Sort of like talk show host Montel does). See also
#13, this topic.
Nuclear Chemistry: Question 12 of 18
This question may require the use of the Chemistry Reference Tables or the Periodic
Table of Elements.
Which equation is an example of artificial transmutation?
1.
2.
3.
4.
238
-> 2He4 + 90Th234
92U
27
4
30
1
13AL + 2He -> 15P + 0n
14
14
0
6C -> 7N + -e
226
4
-> 2He + 86Ra222
88Ra
Correct Answer Number: 2
Explanation: Transmutation means to change or transform atoms of one element
into atoms of another element. Transmutation can be natural or artificial. In fairy
tales it was popular to try to change metal or straw into gold. This still is impossible
but with artificial transmutation, nuclei in a special laboratory are bombarded by high
energy particles: protons, neutrons, or alpha particles (a helium nuclei). If the nuclei
becomes unstable, it can result in another form of the same element (isotope) or a
different element. Answers 1, 3 and 4 are examples of natural transmutation.
Notice in answer 2 there are 15 protons on the left side (13 plus 2 = 15) and 15
protons on the right side; atomic mass on the left is 27 + 4 or 31 and on the right it is
30 + 1 or 31. Remember in nuclear and chemical reactions, equations must be
balanced: 15 protons on the right, 15 protons on the left.
Nuclear Chemistry: Question 13 of 18
This question may require the use of the Chemistry Reference Tables or the Periodic
Table of Elements.
Fissionable uranium-233, uranium 235, and plutonium-239 are used in nuclear
reactors as
1.
2.
3.
4.
coolants
control rods
moderators
fuels
Correct Answer Number: 4
Explanation: The elements given are used as fuel in fission reactors. Water, heavy
water, air, and molten sodium are examples of coolants. Boron and cadmium make
good control rods. Moderators like graphite and heavy water slow down neutrons.
Nuclear Chemistry: Question 14 of 18
This question may require the use of the Chemistry Reference Tables or the Periodic
Table of Elements.
In the reaction 4Be9 + X -> 6C12 + 0n1, the X represents
1.
2.
3.
4.
an alpha particle
a beta particle
an electron
a proton
Correct Answer Number: 1
Explanation: Answer 2 and 3 are the same so eliminate these. The sum of the
protons (sum of the atomic numbers) must be the same on the right side as on the left
side. Likewise the sum of atomic masses must be the same on each side of the
equation.
There are 6 protons on the right side; there must be 6 protons on the left side. Be has
4 so X must have 2 protons (2X). The masses on the right (12 + 1) equal 13 so the
masses on the left must equal 13. Be has a mass of 9 so X must have a mass of 4. An
alpha particle or 2He,4 is the only correct answer. See Ref. Chart J.
Nuclear Chemistry: Question 15 of 18
This question may require the use of the Chemistry Reference Tables or the Periodic
Table of Elements.
Which substance has chemical properties similar to those of radioactive 235U?
1.
2.
3.
4.
235
Pa
Pa
233
U
206
Pb
233
Correct Answer Number: 3
Explanation: Because valence electrons are directly related to chemical properties,
look for an isotope of 235U. Remember isotopes have the same atomic number
(number of protons), the same number of electrons, but a different atomic mass
because the number of neutrons is different. Eliminate answer 1, 2, and 4 because
these are not isotopes of U. They are different elements. 233U is an isotope of 235U so
the chemical properties are similar. See also question #12, topic Periodic Table.
Nuclear Chemistry: Question 16 of 18
This question may require the use of the Chemistry Reference Tables or the Periodic
Table of Elements.
Control rods in nuclear reactors are commonly made of boron and cadmium because
these two elements have the ability to
1.
2.
3.
4.
absorb neutrons
emit neutrons
decrease the speed of neutrons
increase the speed of neutrons
Correct Answer Number: 1
Explanation: Moderators control the speed of a reaction (answers 3 and 4) so control
rods must absorb neutrons. Emitting more neutrons into a nuclear reaction would
make the reaction out of control.
Nuclear Chemistry: Question 17 of 18
This question may require the use of the Chemistry Reference Tables or the Periodic
Table of Elements.
Heavy water and graphite are two examples of materials that are can be used in a
nuclear reactor to slow down neutrons. These materials are called
1.
2.
3.
4.
fuels
shields
coolants
moderators
Correct Answer Number: 4
Explanation: Do not be tricked into picking water as a coolant. The question did not
ask for a coolant: it asked for "traffic cops" that slow down or moderate or keep "the
lid on" a reaction. See also #7, this topic.
Nuclear Chemistry: Question 18 of 18
This question may require the use of the Chemistry Reference Tables or the Periodic
Table of Elements.
Which reaction illustrates fusion?
1.
2.
3.
4.
2
2
4
1H + 1H -> 2He
1
27
24
4
0n + 13Al - > 11Na + 2He
27
4
30
1
13Al + 2He -> 15P + 0n
14
4
1
17
7N + 2He -> 1H + 8O
Correct Answer Number: 1
Explanation: Fusion is the process of joining two light nuclei to form a heavier one.
High pressure and high temperatures are used to make this happen. Tremendous
energy is released when the fusion takes place. Answers 2, 3, and 4 are all examples
of artificial transmutation or bombardment of an element by a neutron or alpha
particle. Only answer 1 shows two light elements combining.
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PERIODIC TABLE
24. Describe what happens with electrons to produce the atomic emissions spectrum of an
element.
25. Write out the orbital diagram, full electron configuration, noble gas abbreviated
configuration, number of valence electrons, for the following species: an atom of sodium,
an atom of iron, an atom of iodine, an ion of sodium, and an ion of iodine.
26. In #25, what is the total number of unpaired electrons for each species.
27. In #25, which element is the ion of sodium isoelectronic with? How about the ion of
iodine?
28. Name a couple of properties of metals, nonmetals, and metalloids and give a couple
examples of each.
29. Redo your entire formulas & naming quizzes and test on separate paper with no reference
materials other than a Periodic Table with symbols.