1. The problem statement, all variables and given/known data This is the question: 2H1 + 3H1 ==> 4He2 + 1n0 +Q Where Q = 17.7 MeV The binding energy per nucleon are given below: 2H1 = 1.12 MeV 1n0 = Null 4He2 = 7.07 MeV " Determine the binding energy per nucleon, in MeV, of tritium (3H1)" 2. Relevant equations 3. The attempt at a solution This is how i do it, The B.E for: 2H1 = 2 x 1.12 = 2.24 MeV 4He2 = 7.07 x 4 = 28.28 MeV From chemical equation shown above, The energy before reaction is equal to energy after reaction. The energy is conversed before and after reaction: 2.24 + 3(X) = 28.28 MeV + 17.7 MeV X = 14.58 MeV which is the B.E per nucleon for 3H1 But when i check up the answer, it turns out to be 2.78 MeV. What wrong with my method of solving the questions? can anyone explain what my mistake?