AUGUST HOMEWORK SET #3 Name:
CHAPTER 3 – Nuclear Chemistry
Chapter
3 Book Assignments: 52 pts
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Assignment:
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Due Date
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Your pts/total
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Read pages 119-130
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Outline Ch 3: nuclear chemistry
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/10
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Answer exercise 3.1 page 122
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/5
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Answer example 3.1 and 3.2 page 127
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/5
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Answer example 3.3 page 128
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/2
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Answer Block’s summary sheet
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/30
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Chapter
3 Homework Assignments: 87 pts
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Assignment:
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Your pts/total
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Natural and Artificial Radioisotopes
List
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/19
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AP Nuclear Example Problems
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/30
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AP Practice exercises #1-14 pages
131-133
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/14
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AP free-response page 133
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/10
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Crib Notes
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/14
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TOTAL POINTS: /139 pts
Block’s Summary Sheet: Chapter 3:
Nuclear
Chemistry 30
pts
1. List the five subatomic particles with their
symbols, representations, masses, and charges. (10 pts)
2. Define
and distinguish between the gamma and x-ray. (3 pts)
3. Give
4 verbs indicating the particle goes on the product side after the yields arrow
and the 4 verbs indicating it goes on the reactant side. (7 pts)
4. What
are the “naturally radioactive” elements? (1)
5. What
are the “transuranium” elements? (1)
6. What
does “dps” stand for? (1)
7. Give
the formula for the rate of radioactive decay and note on formula sheet. What do the variables stand for? (3)
8. What
is “critical mass”? (1)
9. List
2 ways to moderate a fission reaction. (2)
10. List
the fusion reaction. (1)
AP Nuclear Example Problems Name:
30 points
1. Uranium-238 decays
by alpha emission. Write a balanced
equation for this nuclear decay: (3 pts)
2. Bromine-82 decays by
beta emission. Write a balanced equation
for this nuclear reaction: (3 pts)
3. Oxygen-15 decays by
positron emission. Write a balanced
equation for this nuclear reaction: (3 pts)
4. Potassium-40
captures an electron. Write a balanced equation for this nuclear reaction:
(3 pts)
5. Phosphorus-32 is a
radioactive isotope that has a half-life of 14.28 days and is used in treating
leukemia patients. Starting with 45.0
grams of P-32, how many grams would be left after 35.0 days? (5 pts) SHOW THE FORMULA YOU WILL USE:
9. Fission: Uranium-235 is hit with a neutron to produce
strontium-90, xenon 143, and three
neutrons. Write the equation here:
6. Fusion: when 2 HYDROGEN nuclei (tritium H-3 and
deuterium H-2) combine to produce a HELIUM He-4 nucleus, a neutron, and lots of
ENERGY. Write the equation here: (3 pts)
7. Consider C-14-
predict what type of decay will occur, giving a reason and the equation.
(3 pts)
Type of Decay:
Reason:
Equation:
8. Consider C-11-
predict what type of decay will occur, giving a reason and the equation.
(3 pts)
Type of Decay:
Reason:
Equation:
9. What type of decay
will occur for Bi-189? WHY? (2 pts)
10. What type of decay
will occur for Cf – 252? WHY? (2 pts)
Crib Notes Ch 3 – NUCLEAR Chemistry Name:
14 pts
Types
of nuclear decay:
1. Alpha emission: loses 4 mass, loses 2 number, produces a
helium nucleus (helium atom without the 2 electrons, which makes it charged)
4
He
2
2. Beta emission: mass stays the same, gains one atomic number,
produces an “electron”
0
-1
e-
3. positron
emission: mass stays the same, atomic
number goes down by one, produces a positron
0
+1 e+
4. electron
capture: usually a 1s electron is
captured as it is closest to the nucleus, mass stays the same, atomic number
goes down by one, add an electron to the reactant side, produces energy (hv)
0
-1 e-
5. gamma rays: similar to x-rays having no charge and not
mass, the nucleus loses energy during gamma ray emission, travel at the speed
of light, great penetrating power, but less ionizing power than a beta
particle…
Penetrating power:
alpha< beta < neutron < gamma neutron = _________ ?
HALF-LIFE:
Half-life is a first order kinetics reaction meaning that the
rate of reaction is proportional to the concentration of one of the reactants
N
= No (1/2)T/H ln (No
) = kt
N
N = amount left in grams
No = initial amount in grams
T = total time
H = half-life
t ½ = 0.693 k = rate constant
k
Predicting
stability and what type of decay an isotope will undergo:
1. elements with atomic
# > 60 undergo alpha decay (check the isotope’s mass though***)
2. elements with atomic
# > 90 undergo spontaneous fission (= neutrons given off)
3. Calculating
stability using neutron to proton ratio:
(atomic
mass – atomic number)
atomic number
4. usually, the lower
the ratio (closer to one), the more stable the isotope
5. elements less than
83 are more stable than those beyond Bi
6. compare the
isotope’s mass with the “normal” mass off the Periodic Table – the
normal mass is more stable
a. if the isotope’s mass < normal
- positron emission if the
mass is “light”
- electron capture if the
mass is “heavy”
b. if the isotope’s mass > normal, electron
(beta) emission *** common
7. nuclei with an even number of protons or
neutrons tend to be more stable than
those with an odd number WHEN
comparing two elements close together
8. Certain numbers of
protons and neutrons appear to be VERY stable magic
Numbers: 2,8,20,28,50,82,126
Answer
the following about fission and fusion (14 pts):
FISSION
of U-235:
1. U-235 and a neutron
produce Br-87 and La– 146 and 3 neutrons:
2. U-235 and a neutron
produce Ba-139 and Kr-94 and 3 neutrons:
FUSION: tritium and deuterium yield a helium atom and
a neutron:
Natural and Artificial Radioisotopes
List Name:
19 points
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Name of isotope:
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Use of isotope:
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Rn-222 (natural) p.124
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Ra-226 (natural) p.124
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U-238 (natural) p.124
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K-40 (natural) p.124
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H-3
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C-11
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C-14
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Na-24
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P-32
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Cr-51
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Co-57
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Fe-59
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Co-60
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I-131
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Gd-153
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Ra-226
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U-235
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Ir-192
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Am-241
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