a)
K are Z = 19 => 19 e-
1 mol K .............. contine 19x6,022x10la23 e-
2 moli ................................ x = 2,29x10la25 e-
b)
1 mol Cu cantareste 64 g... si contine 29x6,022x10la23 e-
x g ......................... 12,044x10la23 e-
= 4,41 g Cu
1 mol Zn ................. 65 g
2 moli Zn ................. m = 130 g Zn
=> m + x = 134,41 g amestec Cu si Zn
%Zn = 130*100/134,41 = 96,71%
%Cu = 100%- %Zn = 3,28%