Răspuns:
1.
Na2SO4 sulfat de sodiu
2.
Na2SO4
r.a. Na:S:O=2:1:4
r.m. Na:S:O=46:32:64=23:16:32
compozitie procentuala
MNa2SO4=2x23+32+4x16=142g/mol
142g Na2SO4...............46gNa...............32gS.............64gO
100gNa2SO4................x%Na..................y%S................z%O
x=100x46/142=calculeaza
y=100x32/142=calculeaza
z=100x64/142=calculeaza
Explicație:
