Ответ:
Массовая доля определяется = атомная масса элемента*индекс /молекулярная масса
1) Li₂O
w(Li) =[tex] \frac{2*7}{2*7+16}[/tex] *100% = 46,67%
w(O) = 100- w(Li) = 100 — 46,67 = 56,33%
2) CaCl₂
w(Ca) = [tex] \frac{40}{40+35,5*2}[/tex]*100% = 36%
w(Cl) = 100-36 = 64%
3) NaOH
w(Na) = [tex] \frac{23}{23+16+1}[/tex]*100% = 57,5%
w(O) = [tex] \frac{16}{23+16+1}[/tex]*100% = 40%
w(H) = 100-57,5-40 = 2,5%
4) K₂SO₄
w(K) = [tex] \frac{39*2}{39*2+32+4*16}[/tex]*100% = 44,83%
w(S) = [tex] \frac{32}{39*2+32+4*16}[/tex]*100% = 18,39%
w(O) = 100-44,83-18,39 = 36,78%
5) H₂SO₄
w(H) = [tex] \frac{1*2}{1*2+32+4*16}[/tex]*100% = 2,04%
w(S) = [tex] \frac{32}{1*2+32+4*16}[/tex]*100% = 32,65%
w(O) = 100-44,83-18,39 = 65,31%