Ответ:
Mr (HgS) = Ar (Hg) + Ar (S) = 201 + 32 = 233
ω (Hg) = Ar (Hg) ÷ Mr (HgS) ·100% = 201 ÷ 233 · 100% ≈ 86,27%
ω (S) = Ar (S) ÷ Mr (HgS) · 100% = 32 ÷ 233 · 100% ≈ 13,73%
1) m(Na2SO4*10H2O)=x
2) m(Na2SO4)=142x/322=0.441x
3) w(Na2SO4)=m(Na2SO4)/m(общ)=0.441x/(800+x)=0.1
0.441x=80+0.1x
0.341x=80 --------------------x=234.6
S + O2 — SO2
Mg(OH)2 — MgO + H2O
FeO + второе вещ-во не поняла. Se? Ar? As? Ag?
Fe2O3 + 6HNO3 — 2Fe(NO3)3 + 3H2O