The half-life of a certain radioactive isotope is 3.24 years. If
a sample consisting of 6.023x1023...
The half-life of a certain radioactive isotope is 3.24 years. If
a sample consisting of 6.023x1023 atoms were allowed to
decay, what percentage of the original number of atoms have decayed
after 2.0 years?
The half-life of a radioactive isotope represents the average
time it would take half of a collection of this type of nucleus to
decay. For example, you start with a sample of 1000 Oxygen-15
(15O) nuclei, which has a half-life of 122 seconds.
After 122 seconds, half of the 15O nuclei will have
decayed into Nitrogen-15 (15N) nuclei. After another
122s, half of the remaining Oxygen nuclei will have also decayed,
and so on.
Suppose you start with 3.71×10315O nuclei...
Carbon 14 (C-14), a radioactive isotope of carbon, has a
half-life of 5730 ± 40 years. Measuring the amount of this isotope
left in the remains of animals and plants is how anthropologists
determine the age of samples. Example: The skeletal remains of the
so-called Pittsburgh Man, unearthed in Pennsylvania, had lost 82%
of the C-14 they originally contained. Determine the approximate
age of the bones assuming a half-life of 5730.
(a) 14,000 years
(b) 15,000 years
(c) 17,000 years...
Example: The radioactive isotope decays by electron
capture with a half –life of 272 days. •(a) Find the decay constant
of the lifetime. •(b) If you have a radiation source containing ,
with activity 2.00µCi, how many radioactive nuclei does it contain?
•(c) What will be the activity of this source after one year?5
If there is 10umol of the radioactive isotope
32P (half-life 14 days) at t=0, how much 32P
will remain at (a). 7 days (b) 14 days (c) 21 days and (d) 70
days?
I already know the answers, I have the student companion guide
to my biochemistry textbook. It does not tell me how to work out
the problem though. If anyone could help it would be
appreciated!
The answers are (a) 7mmol (b) 5umol (c) 3.5mmol and (d)
0.3umol
BIOPHYSICS
1. Cobalt-60 (60Co), is a synthetic radioactive
isotope of cobalt with a half-life of 5.2713 years. It is an
isotope that emits gamma rays essential to the medical community
for cancer treatments, as well as sterilization of medical devices.
Cobalt-60 is used as a radiation source for medical radiotherapy
where it is used in cancer treatment to control or kill malignant
cells. Cobalt-60 is used as the radiation source in Gamma Knife
equipment that enables non-surgical treatment of brain...
The half-life of the radioactive isotope
polonium-214 is
1.64×10-4 seconds.
How long will it take for the mass of a sample of
polonium-214 to decay from 70.0
micrograms to 17.5
micrograms?
---------- seconds
Radioactive Isotope #1: Uranium-238
How long is its half-life?
How long will it take the original radioactive product to
reduce by 50%?
How long will it take the original radioactive product to
reduce by 25%?
What material is the best application for this isotope?
Describe the disadvantages and advantages of using this element
for dating.
What is the stable daughter product?
1) The radioactive isotope 57Co has a half-life of 272
days.
(a) Find its decay constant.
(b) If your source has an activity of 2.00 mCi, how many
radioactive nuclei does it contain?
(c) What is the activity of your source after one year?
3.A particular radioactive isotope has a half-life of (2.50+A)
hours. If you have (24.5+B) g of the isotope at 10:00 AM, how much
will you have at 7:30PM? Give your answer in grams (g) and with 3
significant figures. A:4 B:5
4.Consider a pure sample of a radioactive isotope with a mass
number of (46+A). If the sample has mass of (25.0+B) micrograms and
the isotope has a half-life of (4.50+C)x106 years,
determine the decay rate for the sample. Give...