Ok. I ended up getting the right answer but don't fully understand the last step.
mf= .005926u
E=mc^2 = 8.9 * 10^-13 J
For difference in # of atoms I did: Atoms initial = (10 g * 1 mol /232.038 g * 6.022 * 10^23) = 2.59526457 *10^22
Atoms...
Homework Statement
Thorium (with half-life T1/2 = 1.913 yr. and atomic mass 228.028715 u) undergoes alpha decay and produces radium (atomic mass 224.020186 u) as a daughter nucleus. (Assume the alpha particle has atomic mass 4.002603 u.)
(a) What is the decay constant of thorium? (Note that...