Take note of the whole number beside each substance in the reaction because these will be used in the stoichiometric calculations below:
Molar mass of k[ag(cn)2]:199 g/mol
Molar mass of Zn(Cn)2: 117.44 g/mol
Avogadro's number: 6.022×10²³ molecules/mol
a.)
35.27 g*(1 mol/199 g)*(1 mol Zn(Cn)₂/ 2 mol K[Ag(CN)₂])*(6.022×10²³ molecules/mol) = 5.34×10²² molecules of Zn(Cn)₂
b.)
35.27 g*(1 mol/199 g)*(1 mol Zn(Cn)₂/ 2 mol K[Ag(CN)₂])*(117.44 g/mol) = 10.41 g of Zn(Cn)₂