Name __________________________________________________ Period ________ Date ______________________
Chem HP Exam Nuclear Chemistry – Version 1
Total Points: _______/100
A
1. Give the nuclide symbol for Polonium-210.
210
84𝑃𝑜
A
2. Which type of nuclear decay has the highest penetrating power?
Gamma radiation
A
3. Which type of nuclear decay causes the least damage?
Gamma radiation
A
4. Complete the following nuclear reaction.
235
92𝑈
+ 10𝑛 →
137
52𝑇𝑒
+
97
40𝑍𝑟
+2 10𝑛
A
5. Write the balanced nuclear reaction for the alpha decay of Uranium-235.
235
92𝑈
→
231
90𝑇ℎ
+ 42𝐻𝑒
A
6. Write the balanced nuclear equation for the beta decay of Neon-22.
22
10𝑁𝑒
→
22
11𝑁𝑎
+ −10𝑒
A
7. Write the balanced nuclear equation for the gamma decay of Bromine-85.
85
35𝐵𝑟
→
85
11𝐵𝑟
+ 00𝛾
A
8. Write the nuclide symbol for the atom that produces scandium-47 when it undergoes
beta decay.
47
20𝐶𝑎
→
47
11𝑆𝑐
+ −10𝑒
A
9. Write the nuclide symbol for the element that is formed when curium-244 emits two
alpha particles and three gamma rays.
244
96𝐶𝑚
→
236
92𝑈
+ 2 42𝐻𝑒 + 00𝛾
A
U
W
S
10. How long does it take a 100.0 g sample of As-81, whose half-life is 33 seconds, to
decay to 6.25 g?
1 𝑡/33𝑠
6.25 𝑔 = (100.0𝑔) ( )
2
6.25𝑔
1 𝑡/33𝑠
=( )
100.0𝑔
2
1 4
1 𝑡/33𝑠
( ) =( )
2
2
𝑡
=4
33𝑠
𝑡 = 130𝑠
11. What percent of a sample remains un-decayed after 43.2 seconds?
A
U
W
S
A
U
W
S
A
U
W
S
43.2 𝑠
𝐴
1 33 𝑠
=( )
= 40.4%
𝐼
2
12. How old is a bone if it presently contains 0.3125 g of C-14 (half-life 5730 years), but it
was estimated to have originally contained 80.000 g of C-14?
𝑡
1 5730 𝑦
0.3125 𝑔 = (80.000 𝑔) ( )
2
𝑡
0.3125 𝑔
1 5730 𝑦
=( )
80.000 𝑔
2
𝑡
1 8
1 5730 𝑦
( ) =( )
2
2
8=
𝑡
5730 𝑦
𝑡 = 45800 𝑦
13. What is the half-life of a radioactive isotope if a 500.0 g sample decays to 62.5 g in
24.3 hours?
24.3 ℎ
ℎ
1
62.5 𝑔 = (500.0 𝑔) ( )
2
62.5 𝑔
1
=( )
500.0 𝑔
2
1 3
1
( ) =( )
2
2
3=
24.3 ℎ
ℎ
24.3 ℎ
ℎ
24.3 ℎ
ℎ
ℎ = 8.10 ℎ
14. The oxygen isotope O-16 has a mass of 15.99491 units. Calculate its mass defect,
given that the mass of a proton is 1.007825 amu and the mass of a neutron is
1.008665 amu.
A
U
W
S
A
U
W
S
J
8 protons = 8(1.007825 amu)= 8.062600
8 neutrons = 8(1.008665 amu)= 8.069320
8.062600+8.069320 = 16.13192 amu
16.13192 amu - 15.99491 = 0.13701 amu
15. Calculate the binding energy of O-16. (1 amu = 1.660538782 × 10−27 kg; c = 3.00 x 108
m/s)
𝑚 = 0.13701 𝑎𝑚𝑢 ×
1.660538782 × 10−27 𝑘𝑔
= 2.2751 × 10−28 𝑘𝑔
1 𝑎𝑚𝑢
𝐸 = 𝑚𝑐 2 = (2.2751 × 10−28 𝑘𝑔) (3.00 × 108
𝑚 2
) = 2.0476 × 10−11 𝐽
𝑠