half-life
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Section 3 Uses of Nuclear Chemistry. Chapter 18. Half-Life. The _________ is the time required for half of a sample of a radioactive substance to disintegrate by radioactive decay - PowerPoint PPT PresentationTRANSCRIPT
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Half-Life
• The _________ is the time required for half of a sample of a radioactive substance to disintegrate by radioactive decay
• The half-life of a radioactive isotope is a ___________ and is not influenced by any external conditions, such as temperature and pressure.
Section 3 Uses of Nuclear ChemistryChapter 18
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Half-Life
Radioisotope Half-life Radioisotope Half-life
Bismuth-212 60.5 min Polonium-215 0.0018 sec
Carbon-14 5930 yrs Polonium-216 0.16 sec
Chlorine-36 400 000 yrs Radium-226 1602 yrs
Cobalt-60 5.26 yrs Sodium-24 15.0 hrs
Iodine-131 8.14 days Strontium-90 19.9 yrs
Iron-59 46.3 days Uranium-235 710 mill yrs
Phosphorus-32 14.3 days Uranium-238 4.5 bill yrs
Chapter 18Section 3 Uses of Nuclear Chemistry
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Half-Life
Example Problem:
212 Bi 0 + 212 Po
83 - 1 84
If you start with 200 g, how much is left after 181.5 min?
Answer:
The half-life of bismuth-212 is ___________.
How much is left after one half-life (60.5 minutes)?
How much is left after 2 half-lives (121 minutes)?
How much is left after 3 half-lives (181.5 minutes)?
Chapter 18 Section 3 Uses of Nuclear Chemistry
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Half-Life
Practice Problem:Radium-226 undergoes alpha decay.
(A) Write the transmutation equation for this change.
(B) What is the name if the new substance that is produced?
(C) If you start with 4000 g, how much will be left after 6408 years?
Answers:
(A)
(B) Radon-222
Chapter 18Section 3 Uses of Nuclear Chemistry
226Ra
88
4
2
222Rn
86
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Half-Life
Practice Problem (continued):
Radium-226 undergoes alpha decay.
(C) If you start with 4000 g, how much will be left after 6408 years?Answer:What is the half-life of Radium-226? How much is left after 1 half-life? How much is left after 2 half-lives (3204 years)? How much is left after 3 half-lives (4806 years)? How much is left after 4 half-lives (6408 years)?
Chapter 18 Section 3 Uses of Nuclear Chemistry
1602 years
2000 g1000 g
500 g
250 g
Copyright © by Holt, Rinehart and Winston. All rights reserved.
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Half-Life
Practice Problem:Carbon-14 undergoes beta decay.
(A) Write the transmutation equation for this change.
(B) What is the name if the new substance that is produced?
(C) If you start with 600 g, how much will be left after 17,790 years?
Answers:
14C
6
0
-1
14N
7
(A)
(B) Nitrogen-14
Chapter 18 Section 3 Uses of Nuclear Chemistry
Copyright © by Holt, Rinehart and Winston. All rights reserved.
ResourcesChapter menu
Half-Life
Practice Problem (continued):Carbon-14 undergoes beta decay.
(C) If you start with 600 g, how much will be left after 17,790 years?
Answer:
What is the half-life of carbon-14?
How much is left after 1 half-life?
How much is left after 2 half-lives (11,860 years)?
How much is left after 3 half-lives (17,790 years)?
5930 years
300 g
150 g
75 g
Chapter 18 Section 3 Uses of Nuclear Chemistry