Răspuns :
e)
Ar = (c1xA1 + c2A2)/100
=> 6354 = 63c1 + 65c2
100 = c1 + c2 => c1 = 100-c2
=> 6354 = 63(100-c2) + 65c2
=> c2 = 54/2 = 27%
=> c1 = 100-27 = 73%
poza)
a.
A(Ca) = 40 => 1 mol-atomi Ca = 40 g
=> 40 g Ca ....................... 6,022x10la23 atomi Ca
500 g Ca ..................... N = 7,53x10la24 atomi Ca
b.
A(Fe) = 56 => 1 mol-atomi Fe = 56 g
1 mol Fe ............................ 56 g
10000 moli Fe ............... m = 560000 g Fe sau 560 Kg Fe
c.
Z(K) = 19 => 19e-
1 mol K .................................... 19x6,022x10la23 e-
2 moli K .................................... N = 2,29x10la25 e-
d.
A(Cu) = 64 => 1 mol Cu = 64 g
1 mol Cu ............. 64 g .............. 6,022x10la23 atomi
m g ................. 12,044x10la23 atomi
= 128 g Cu
A(Zn) = 65 => 1 mol-atomi Zn = 65 g
1 mol Zn ........................... 65 g
2 mol Zn ............................ n = 130 g Zn
=> amestec = 128+130 = 258 g
%Cu = 128x100/258 = 49,61%
%Zn = 100-49,61 = 50,39%