miu,CaCl2= 40gCa+71gCl--> = 111g/mol
111g clorura de calciu pura contine....40gCa
x.............................................................15gCa
x=41.625g CaCl2 pura
100g clorura impura ....contine 60g clorura pura
x............................................41,625g..............................calculeaza x!!!!!!