91Ó°ÊÓ

At \(8 : 00\) A.M., a patient receives a 58 -mg dose of I- 131 to obtain an image of her thyroid. If the nuclide has a half-life of 8 days, what mass of the nuclide remains in the patient at \(5 : 00\) p.M.the next day? (Assume the nuclide is not excreted from the body.)

A sample of \(F-18\) has an initial decay rate of \(1.5 \times 10^{5}\) dis/s. How long will it take for the decay rate to fall to \(2.5 \times 10^{3}\) dis/s? \((F-18\) has a half- life of 1.83 hours.)

A sample of T1-201 has an initial decay rate of \(5.88 \times 10^{4}\) dis/s. How long will it take for the decay rate to fall to 287 dis/s? \((T 1-201\) has a half- life of 3.042 days.)

An ancient skull has a carbon-14 decay rate of 0.85 disintegrations per minute per gram of carbon \((0.85\) dis/ min \(\cdot \mathrm{g}\) C). How old is the skull? (Assume that living organisms have a carbon-14 decay rate of 15.3 dis/ min \(\cdot \mathrm{g} \mathrm{C}\) and that carbon- 14 has a half- life of 5730 yr.)

A mammoth skeleton has a carbon-14 decay rate of 0.48 disintegrations per minute per gram of carbon (0.48 dis/min \(\cdot \mathrm{g} C\)). When did the mammoth live? (Assume that living organisms have a carbon-14 decay rate of 15.3 dis/min \(\cdot \mathrm{g} \mathrm{C}\) and that carbon- 14 has a half-life of 5730 yr.)

Write the nuclear equation for the fusion of \(\mathrm{H}-3\) with \(\mathrm{H}-1\) to form \(\mathrm{He}-4 .\)

A breeder nuclear reactor is a reactor in which nonfissionable (nonfissile) \(\mathrm{U}-238\) is converted into fissionable (fissile) \(\mathrm{Pu}-239 .\) The process involves bombardment of U- 238 by neutrons to form \(U-239,\) which then undergoes two sequential beta decays. Write nuclear equations for this process.

Write the series of nuclear equations to represent the bombardment of Al-27 with a neutron to form a product that subsequently undergoes an alpha decay followed by a beta decay.

Rutherfordium-257 was synthesized by bombarding Cf-249 with \(\mathrm{C}-12\) . Write the nuclear equation for this reaction.

If 1.0 g of matter is converted to energy, how much energy is formed?