Question

The radioactive isotope which is often used for diagnosis and imaging in nuclear medicine has a half-life of 3 days. What was the initial mass of the isotope before decay, if the mass in 6 weeks was 5g?

Answer #1

In this question we have to find initial mass of the decaying substance.

Radioisotopes are often used in diagnostic imaging for detecting
disease. The isotope F-18, which has a half-life of 110 min, is
used in medical imaging. What percentage of the original acitivity
in the sample remains after 300 min? Remember that half life is
given by k=0.693/t1/2 ? Show your work.

The radioactive isotope thorium 234 has a half-life of
approximately 578 hours.
If a sample has an initial mass of 64 mg, a function that models
the mass in mg after t hours is a(t) =
The initial mass will decay to 12 mg after ______ hours
Radioactive decay equation:
a(t) = a0⋅2 ^ (−t / h)
a0 = starting amount
a(t) = amount after t hours
h = half life in hours

Radioactive iodine is used in nuclear imaging techniques such as
photoemission tomography (PET scans) and X-ray CT scans. It decays
according to the nuclear reaction below
I^123 à Te^123 + electron neutrino
The following experiments were run to determine the order of the
reaction:
Rate (mol/L hr) [I^123]
0.00725
0.137
0.137
0.275
0.00362
0.0685
(a)write the generic rate law for this nuclear decay
(rate=k[I^123]^n)
(b) what Is the value of k with its correct units?
(c) what is...

Consider a pure sample of a radioactive isotope with a mass
number of (52). If the sample has mass of (25.0) micrograms and the
isotope has a half-life of (12.5)x10^6 years, determine the decay
rate for the sample. Give your answer in decays/second and with 3
significant figures.

The radioactive isotope 234Pa has a half-life of 6.70
h. A sample containing this isotope has an initial activity
(t = 0) of 35.0µCi. Calculate the number of nuclei that
decay in the time interval between t1 = 7.0 h
and t2 = 14.0 h.
___________ Nuclei

When radioactive tracers are used for medical scans, the tracers
both decay in the body via radiation, as well as being excreted
from the body. The effective half-life of the radioactive tracer is
due to the combination of both effects. Medical experiments show
that a stable (nonradioactive) isotope of a particular element have
an excretion half-life of 6 days. A radioactive isotope of the same
element has a half-life of 9 days. What is the effective half-life
of the radioactive...

The
radioactive isotope Gold-198 has a half-life of 64.80 hrs. A sample
containing this isotope has an initial activity of 40.0 μCi.
Calculate the number of nuclei that will decay in the time interval
from 10 hrs to 12 hrs.[10 marks]

The radioactive isotope 133 54Xe is used in pulmonary
respiratory studies to image the blood flow and the air reaching
the lungs. The half-life of this isotope is 5 days.
A hospital needs 0.100 g of 133 54Xe for a lung-imaging test. If
it takes 10days to receive the shipment, what is the minimal amount
mXe of xenon that the hospital should order?
Express your answer numerically in grams

Radioactive gold-198 is used in the diagnosis of liver problems.
198Au decays in a first-order process, emitting a β particle
(electron). The half-life of this isotope is 2.7 days. You begin
with a 5.6-mg sample of the isotope. Calculate how much gold-198
remains after 3.5 days.

The radioactive isotope 198Au has a half-life of 64.8 hr. A
sample containing this isotope has an initial activity (t = 0) of
1.5x 10^12 Bq. Calculate the number of nuclei that decay in the
time interval between t1 = 10 hr and t2 = 12 hr.
Please show and explain work, and do not use calculus to solve
it.

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