MCaCl2=111g/mol
n=m/M=38/111=0,34234234 moli CaCl2
1 mol Ca.....................6,023*10^23 ioni
0,34234234 moli..............x=2,0619*10^23 ioni Ca
1 mol Cl2...........................2*6,023*10^23 ioni
0,34234234 moli..................x=4,123855 ioni Cl2