1.Substanța: K2SO4 - Sulfat de Potasiu
2. Masa moleculara=M= 2*Ak + As + 4* Ao
M = 2*39 + 32 + 4*16
M = 78+32+64
M = 174 u.a.m
3. raport atomic= r.a.
r.a. = 2:1:4
4. raport de masa=r.m.
r.m.=78:32:64 |:2
r.m.=39:16:32
5.
174g K2SO4.........78g K.........32g S...........64g O
100g K2SO4.........x g K.............y g S............z g O
[tex]x = \frac{100 \times 78}{174} = 44.83\% [/tex]
[tex]y = \frac{32 \times 100}{174} = 18.39\%[/tex]
[tex]z = \frac{100 \times 64}{174} = 36.78\% [/tex]
