(2) Phosphorus-32 (mass = 31.973907) is a beta emitter and has a half-life of 14.28
days.
a) to what isotope does the
32
P decay? Write a balanced equation.
31Si 30.975362 u
32Si 31.974148 u
33Si 32.977920 u
31P 30.973762 u
31S 30.979554 u
32S 31.972070 u
33S 32.971456 u
33P 32.971725 u
b ) Calculate the % composition of the32
P and the daughter by mass after a sample
of pure phosphorus has decayed for 14, 21, 28 and 60 days.
3) A certain rock contains 0.805 g of ur
anium-238 and 0.150 g of lead-206. No other
isotopes of lead are present. How long a
go did the uranium first begin to decay?
4) Stable carbon is a mixture of carbon-
12 (atomic mass = 12.000000 u) and carbon-13
(atomic mass = 13.003355 u). Carbon-12 has a natural abundance of 98.90%.
Calculate the average atomic mass of
carbon and compare the value to the mass
given in the periodic table.
5) A deuterium nucleus (
2
H) contains one proton (mass = 1.00727647 u) and one
neutron (mass = 1.00866490 u). The mass of a deuterium nucleus is 2.0140 u.
a) Why is the mass of the bound nucleus lower
than the masses of the individual
particles.
b ) Compute the total binding energy of the
2
H nucleus.
c) Compute the binding energy per nucleon.
6) How small is a nucleus and how dense is
it? Experiments show that the radius of a
nucleus goes roughly as R = (1.2x10-15m)A1/3
for mass number A.
a)
Use this relationship to determine
the radius of hydrogen-1, carbon-12 and uranium-238.
Estimate the density of each nucleus assuming the shape of a perfect sphere.
c)
How many tons of nuclear material at
the calculated densities would fill a
volume of 1 cubic centimeter.
7) The
80
Br nuclide decays eith
er by beta decay or
electron capture.
a) What is the product of each process?
Which process releases more energy? Neglect the mass of
the electron involved.
80
Br = 79.918528 u,
80
Kr = 79.916380 u,
80
Se = 79.916520 u
This post was edited by tidus_ffx2 on Oct 24 2013 05:47pm