text: how to determine calcium in cacn2 (how much percent of ca contains  cacn2  -by dry way)?   to determine the mass percent of ca in ca(cn)2 all you have to do is find the mass of ca, divide it by the total mass of ca(cn)2, then multiply by 100.    therefore:  mass of ca = 40.08 amu (or g/mol) mass of ca(cn)2 = 92.10 amu (or g/mol)  (40.08 amu / 92.10 amu) x 100 = 43.52% ca in ca(cn)2