- #1

- 16

- 0

**Question and formulas**

The nucleus of a Sulphur atom has an atomic mass of 32 and an atomic number of 16. If the mass of this atomic nucleus is 31.972072 amu (atomic mass unit), find its binding energy in MeV.

Table of conversions/constants

mass of proton 1.007826

mass of neutron 1.008665

Speed of light 2.99792458 x 10^8

1 amu = 1.6606x 10^-27 kg

1 Mev= 1.6022x 10^-13 J

E=mc^2, Be= (#n)(mass of n) + (#p)(mass of p) - (nucleus's mass)

**Attempt at the solution**

We have its amount of neutrons and protons, so we multiply 16p with 1.007826 and add it with 16n times 1.008665. We get 32.263856 and subtract it by 31.972072 amu to get its mass defect (0.291784). Afterwards we multiply it to get its binding energy using the formula E=mc^2 . So E= (0.291784) (1.6606x10^-27) (2.99792458 x 10^8) ^2 to get it into joules. Then we divide it by 1.6022x 10^-13 J to turn it into MeV. However i end up with the result 271.8010848 MeV but my online assignment says its wrong help?