1. The problem statement, all variables and given/known data Problem: Calculate the binding energy of 147N (nuclear mass of 13.999234 amu) in Joules per nucleon. According to periodic table, the mass of N is 14.0067 amu. 2. Relevant equations E = mc2 3. The attempt at a solution Calculate mass defect: 13.999234 - 14.0067 = 0.007466 Convert to kg: 0.007466 * (1.66053886 * 10-27) = 1.23976 * 10-29 Use mass/energy equivalence (E = mc2) to calculate energy of the mass defect: E = (1.23976 * 10-29)(3 * 108)2 = 1.115784 * 10-12[/EQ] The result *should* be the binding energy of the entire molecule (I would have thought per nucleon would be just dividing this by 14) - but the answer my book gives is 1.19773*10-12 J/nucleon. Where have I gone wrong?