If someone has the time to help with the following question it would be really helpful.

Question

The problem is
209/83bi+64/28NI=272/111Rg+1/0n
How to calculate the energy change in J/mol reactants?

AMU amounts:
Bi=208.980384
Ni= 63.927969
Rg=272.1535

What I have done is
1. subtract products from reactants.
2. multiply the result by 1.66054x10^-27kg
3. multiply that by 8.98x10^16 (which is c^2 in e=mc^2
4. multiply that result by 6.022x10^23

The answer is 1.03x10^11. But I am not getting that.
can someone explain how to do this problem? I keep getting the following answer which by the book is wrong:

1. difference between reactant and products=.253807 amu
2. .253807 x 1.66054x10^-27=4.2145x10-28
3. 4.2145x10-28x8.98x10^16=3.784x10-11
4. 3.784x10-11 x6.022x10^23=2.279x10^13

The book has 1.03x10^11. Why??

Answer 1

I have looked at this problem (many times) and I don't see anything wrong with your answer. I have thought of dividing your final answer by 2 since the problem asks for J/mol REACTANTS and you have two mols reactants but that doesn't get close to the answer either. I have sent a link to my colleague Bob Pursley and asked him to take a look. He probably will post here.

Answer 2

You are almost correct on the mass difference, however it is negative (-.253807 amu) as the mass of products is greater than reactants, so high energy was required in the form of high KE in the Nickel atom.
Converting that to energy needed for the reaction, correct, -4.2145x10-28 kg then to energy
E=deltaM*c^2=-4.2145x10-28*(2.9979 x 108 m/s)2 = -3.784x10-11 Joules
then finally per mole reactant= yes, I would divide by two since Reactants was stated, however, I think they meant mole of Bi (then don't divide it).

So my truthometer rates the book answer in error. If you want to explore on this, calculate the nuclear binding energy of the product (including sign), and then look how unstable it is.