Question

The radioactive isotope ^{234}Pa 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 *t*_{1} = 7.0 h
and *t*_{2} = 14.0 h.

___________ Nuclei

Answer #1

Given that -

m = 35.0 uCi, Half-life, Hf = 6.70 h, t1=7.0 h, t2 = 14.0 h

Now, use the expression -

mr = mo/2^(t/hf)

at t1 mr = 35.0uCi/ 2^(7.0hr/6.7hr)

mr = 35.0/ 2^1.045

mr = 35.0/2.063

mr = 16.962 uCi remaining mass after t1

Again -

at t2 mr = 35.0/ 2^(14.0/6.7)

mr = 35.0/2^(2.089)

mr = 35.0/4.254

mr = 8.226 uCi remaining mass after t2

Therefore, the number of nuclei decayed ( n ) between t1 and t2 =
mr after ti - mr after t2

= 16.962 uCi - 8.226 uCi

= 8.736 uCi

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.

The radioactive isotope 198Au has a half-life of 64.8 hours. A
sample containing this isotope has an initial activity at (t=0) of
1.50e-12 Bq. Calculate the number of nuclei that will decay in the
time interval between t1=10 hours and t2=20 hours
Answer is 4.60e16 but I'm not sure how. Thanks and please show
work

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 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

A radioactive isotope has a half-life of 72.0 min. A sample is
prepared that has an initial activity of 1.40×1011
Bq.
Q1: How many radioactive nuclei are initially present in the
sample?
Q2: How many are present after 72.0 min?
Q3: What is the activity after 72.0 min?
Q4: How many are present after 144 min?
Q5: What is the activity after 144 min?

Radioactive decay can be used to determine the age of an object.
If you know the number of radioactive nuclei with which an object
started, the number of radioactive nuclei currently present, and
the half-life of the isotope, you can calculate the time since the
object was created.
Suppose an object was created with 3.270×109 nuclei of a
particular isotope that has a half-life of 1.66×103 yr.
At this point in time 1.079×109 nuclei of this
particular isotope remain. What...

A freshly prepared sample of a certain radioactive isotope has
an activity of 10.4 mCi. After 4.20 h, its activity is 8.00
mCi.
(a) Find the decay constant and half-life. decay constant s-1
half-life h
(b) How many atoms of the isotope were contained in the freshly
prepared sample?
(c) What is the sample's activity 33.7 h after it is prepared?
mCi

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 4.00×103
15O...

The radioactive plutonium isotope, 239Pu, has an half-life of 24
100 years and undergoes alpha decay. The molar mass of 239Pu is
239.0521634 amu. The sample initially contains 10.0 g of 239Pu.
(a) Calculate the number of moles of 239Pu that are left in the
sample after 15 000 years. (4)
(b) Determine the activity of 239Pu after 15 000 years, in units
of Bq.

The radioactive plutonium isotope, 239Pu, has an
half-life of 24 100 years and undergoes alpha decay. The molar mass
of 239Pu is 239.0521634 amu. The sample initially
contains 10.0 g of 239Pu. (a) Calculate the number of
moles of 239Pu that are left in the sample after 15 000
years. (4) (b) Determine the activity of 239Pu after 15
000 years, in units of Bq.

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 44 seconds ago

asked 5 minutes ago

asked 13 minutes ago

asked 13 minutes ago

asked 22 minutes ago

asked 27 minutes ago

asked 34 minutes ago

asked 36 minutes ago

asked 42 minutes ago

asked 46 minutes ago

asked 51 minutes ago

asked 1 hour ago