Может все таки так:
Fe2O3 + 3H2SO4 = Fe2(SO4)3 + 3H2O?
Cu²⁺ + 2OH = Cu(OH)₂↓
CuCI₂ + 2NaOH= Cu(OH)₂↓ + 2NaCI
<span>Cu</span>²⁺ +2<span>CI</span>⁻<span> + 2Na</span>⁺ + 2<span>OH</span>⁻<span>= Cu(OH)₂↓ + 2Na</span>⁺ + 2<span>CI</span>⁻
212=x --------- 222=y ---------------- 200
Na2CO3 + CaCl2 = 2NaCl + CaCO3
106 ---------- 111 ------------------- 100