An unknown radioactive element decays into non-radioactive
substances. In 340 days the radioactivity of a sample decreases by
37 percent. (a) What is the half-life of the element? (b) How long
will it take for a sample of 100 mg to decay to 74 mg? time needed:
(days)
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
When studying radioactive material, a nuclear engineer found
that over 365 days, 1,000,000 radioactive atoms decayed to 973,133
radioactive atoms, so 26,867 atoms decayed during 365 days.
a. Find the mean number of radioactive atoms that decayed in a
day.
b. Find the probability that on a given day, 50 radioactive
atoms decayed.
Thanks in advance!
3.
a. A researcher wants to study how long (in days) patients aged
30-39 who are admitted to a hospital for coronavirus treatment
spend in the hospital before being discharged. Preliminary data
suggests that
? = 4 days is a safe assumption. Assuming the recovery times have
standard deviation 4 days (which would say that virtually all
patients recover in some number of days +/- about 12 days), use the
formula
? = ?^2 * ?^2 / ?^2
To find...
1a) Why are radioactive half-lives independent of
temperature?
1b) Element ‘X’ has several isotopes. How are they different and
how are they the same? Why do you think some of them are unstable
while others may be stable?
In a survey, 39 people were asked how much they spent on their
child's last birthday gift. The results were roughly bell-shaped
with a mean of $45 and standard deviation of $14.
Calculate, state, and interpret a 95% confidence interval to
estimate the mean amount of money parents spend on their child's
birthday gift. Round to the nearest 100th where necessary.
1. When a radioactive element decays, it is because the balance
of neutrons and protons inside the nucleus was unstable. Explain
what happens in each of these kinds of decay to make the nucleus
more stable (these are the three most common decay types):
a. Fission
b. Beta-decay ( β )
c. Alpha-decay ( α )
Which of these is more often associated with the production of
energy (and weapons)?
Why do you think that is?
The element technetium (atomic number 43) is radioactive and one
of its isotopes, 99Tc, is used in medicine for diagnostic imaging.
The isotope is usually obtained in the form of the pertechnetate
anion, TcO4-, but its use sometimes requires the technetium to be
in a lower oxidation state. Reduction can be carried out using Sn2+
in an acidic solution. The skeleton equation is TcO4- + Sn2+ → Tc4+
+ Sn4+ (acidic solution) Balance the equation by the ion–electron
method.
The element technetium (atomic number 43) is radioactive and one
of its isotopes, 99Tc, is used in medicine for diagnostic imaging.
The isotope is usually obtained in the form of the pertechnetate
anion, TcO4-, but its use sometimes requires the technetium to be
in a lower oxidation state. Reduction can be carried out using Sn2+
in an acidic solution. The skeleton equation is TcO4- + Sn2+ → Tc4+
+ Sn4+ (acidic solution) Balance the equation by the ion–electron
method.
What is the half-life (T1/2) of a radioactive element with the
following conditions?
-Initial Activity = 1000 milliCuries
-Final Activity = 400 milliCuries
-Elapsed Time= 20.0 days