11. When three helium-4 atoms fuse to form an atom of carbon-12,
is there a gain, or loss, of mass, and how much? Is energy absorbed,
or given off, and how much? (Recall that carbon-12 is the standard
for the amu scale, with a mass of exactly 12 amu.)
12. When two oxygen-16 atoms fuse in a reaction at the centers
of very heavy stars to produce an atom of sulfur-32, how much mass
is lost, and how much energy released? (Mass of 32S = 31.9721 amu;
16O = 15.9949.)
13. When an atom of nickel-60 and a helium-4 atom fuse to form
zinc-64, what is the change in mass? Is energy given off, or absorbed,
and how much?
14. Thorium-232 is the beginning of a radioactive decay series
(similar to the two uranium series) in which six alpha particles and
four beta particles are emitted before a stable isotope is reached.
What is the final stable element, and what is its mass number?
15. Plutonium-241 is the beginning of a decay series during
which eight alpha and five beta particles are emitted. What is the
final stable element, and what is its mass number?