1. The problem statement, all variables and given/known data Specific Activity of a sample of rubidium chloride is 478 Bq per gram knowing that activity is coming from Rb-87, calculate the half life of radioisotope - Molar mass of the RbCl natural is 120.9256 gram - Isotope composition of natural Rb is 72.15% and 27.85% respectively for Rb -85 and Rb-87. 2. Relevant equations Calculate Half life of radioisotope from mixture. 3. The attempt at a solution First find the number of Rb-87 atoms in solution. Find the decay constant so we can get half life. is this process is correct?