Revision/ Ch 11/ Q10
Q1
The nucleus of the
deuterium atom, called the deuteron, consists of a proton and a neutron.
Calculate the deuteron’s binding energy in MeV, given that its atomic mass, the
mass of a deuterium nucleus plus an electron, is 2.014 102 u.
[2.224 MeV]
Q2
The half-life of
the radioactive nucleus 22688Ra is 1.6 ´ 103 yr. If a sample initially contains 3.00 ´ 1016 such nuclei, determine
(a)
the initial activity in curies,
(b)
the number of radium nuclei remaining after 4.8 ´ 103 yr, and
(c)
the activity at this later time.
[11mCi, 3.8 ´
1015 nuclei, 1.4 mCi]
Q3
A 200.0 - mCi
sample of a radioactive isotope is purchased by a medical supply house. If the
sample has a half-life of 14.0 days, how long will it keep before its activity
is reduced to 20.0 mCi?
[46.5 d]
Q4
A radioactive
sample contains 3.50 mg of pure 11C, which has a half-life of 20.4 min.
(a)
How many moles of 11C are present initially?
(b)
Determine the number of nuclei present initially.
(c)
What is the activity of the sample initially and after 8.00 h?
[3.18 ´ 1027 mol, 1.91 ´ 1017 nuclei, 1.08 ´ 1014 Bq, 8.92 ´ 106 Bq]
the exercises are very helpful in revision thank you .. :)
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