4. Adapting Eq. 43-20, there are
N
Pu
=
M
sam
A
1000 g
239 g/mol
6.02
× 10
23
/mol
= 2.5
24
plutonium nuclei in the sample. If they all fission (each releasing 180 MeV), then the total energy releaseis 4.5
26
MeV.