Question

What is the binding energy of one mole of 234/90 Th if the mass defect is 1.908 g/mol?

Answer 1

You can find the binding energy using E=mc^2, where E is the binding energy, m is the mass defect, and c is the speed of light.

If you find the mass of an atom's nucleus, the number you come up with will be LESS than the sum of the individual components (i.e. the protons and neutrons). There is a mass defect. This is because that part of the total mass, the mass defect, has actually been converted to energy that holds the nucleus of the atom together (the binding energy).