Question

Find the energy (in mev) released when decay converts 88x226 (atomic mass = 226.02540 u) into 86y222 (atomic mass = 222.01757 u). the atomic mass of an particle is 4.002603 u.

Answer 1

The energy (in MeV) released when decay converts 88x226 into 86y222 is ΔE = 4.87 MeV.

Solution:

Use Energy Conservation. By α decay converts, we mean that the parent particle turns into an alpha particle and daughter particles. Adding the mass of the alpha and daughter radon, we get

m = 4.00260 u + 222.01757 u = 226.02017 u

The parent had a mass of 226.02540 u, so clearly some mass has gone somewhere. The amount of the missing mass is,

Δm = 226.02540 u -- 226.02017 u = 0.00523 u,

which is equivalent to an energy change of,

ΔE = (0.00523 u)
`((931.5 MeV))/((1u))` ,

ΔE = 4.37 MeV

Hence, the energy released when decay converts is 4.37 MeV.