Question

Antimoniul are masa atomica 121,855. Stiind ca in compozitia lui naturala se intalnesc doi izotopi 121Sb si 123Sb. Care sunt proportiile in care se gasesc in natura cei doi izotopi?

Answer 1

notam raportul molar 121Sb:123Sb=x:y
Arelativ=(n1*A1+n2*A2)/(n1+n2)
121,855=(121x+123y)/(x+y)
121,855x+121,855y=121x+123y
0,855x=1,145y => x=1,333y
x+y.................100%
x........................a%
y........................b%
a=1,333y*100/2,333y=57,14% 121Sb
b=1*100/2,333y=42,85% 123Sb