Calculate the number of Cl- and …

The chemical formula and molar mass of calcium chloride are respectively CaCl2 and 111 g respectively. Thus, there are 6.022$\times$1023 formula units in 111g of CaCl2. So,
number of formula units of CaCl2 in 111 g of CaCl2 = 6.022 $\times$1023
number of formula units of CaCl2 in 1g of CaCl2 = $\frac{(6.022\times1023)}{111}$

number of formula units in 222g of CaCl2 =$\frac{(6.022\times1023\times222)}{111}$ 
= 12.044 $\times$ 1023
Now, each formula unit of CaCl2 contains one Ca2+ ion and two Cl- ions. Therefore
number of Ca2+ ions in one unit of CaCl2 = 1
number of Ca2+ ions in 12.044 $\times$ 1023 units of CaCl2 = 1 $\times$ 12.044 $\times$ 1022 = 1.2044 $\times$ 1024
Similarly
number of Cl- ions in one unit of CaCl2 = 2
number of Cl- ions in 12.044 $\times$ 1023 units of CaCl2 = 2 $\times$ 12.044 $\times$ 1023
= 2.4088 $\times$ 1024
Hence, there are 1.2044 $\times$ 1024 Ca2+ ions and 2.4088 $\times$ 1024 Cl- ions in 222 g of CaCl2.