Răspuns:
a)
(91,7×56 + 5,8 × 54 + 2,2 × 57 + 0,3 × 58 ) / 100 =55.912≈56u.a.m
b)
MFe=56g/mol
1 mol Fe..................56g.................6,022×10²³atomi
xg.......................24,088×10²³atomi
x= 24,088×10²³atomi×56/6,022×10²³atomi=224g Fe
c)
MFe=56g/mol
n=m/M → m=n×M=4×56=224gFe
Explicație:
