Sure!
The way I knew there were 6 water molecules in the strontium chloride was that the picture of the label shows: SrCl2 6 H2O (blow it up to see that, probably can't see it on a phone)
To get the percentage of pure strontium chloride present, you find the molecular weight of SrCl2 (google it as mw SrCl2; google is a pretty smart chemist; alternatively, add up the molecular weights of all the elements in it). It is 158.5 g/mole. mw is short for molecular weight
Same for SrCl2 6H2O (googling mw SrCl2 6H2O) shows it to be 266.6
So the percentage of SrCl2 in SrCl2 6H2O is 158.5/266.6 = 0.5945 = 59.45% ~60%
I didn't take the starting purity of 95% on the label into account, but you could add 5% more if you want to do that. Problem is it may be a minimum and the actual purity may be higher.
Same way for CaCl2: mw = 111 g/mole
mw ClCl2 2H2O = 147
% CaCl2 --> 111/147 --> ~76% I know that Dowflake always listed it as 77%, so I used that instead since these products may not be fully 2 H2O and I figured Dow knew the "most likely" hydration level.
Thanks for the crash course. I'll pour over this.