When Americium (Am-241) undergoes alpha decay(He-4) it forms neptunium (Np-237) based on the following pathway:
²⁴¹Am₉₅ → ²³⁷Np₉₃ + ⁴He₂
The energy released in given as:
ΔE = Δmc²
where Δm = mass of products - mass of reactants
= [m(Np-237) + m(He-4)] - [m(Am-241)]
= 237.0482+4.0015-241.0568 = -0.0073 g/mol = -7.3 * 10⁻⁶ kg/mol
ΔE = -7.3*10⁻⁶ kg/mol * (3*10⁸ m/s)² = -5.84*10¹¹ J/mol
