1) 120*2.5%=3
2) 10*5%=0,5
3) 120+10=130 (масса получ. р-ра)
4) 3+0,5/130 * 100%= 2,7
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CnH2n+1+80
CnH2n+1+35,5
14n+81 : 14n+36,5 = 45,3:31,95
n=5.
K₂CO₃ + H₂SO₄ = K₂SO₄ + H₂O + CO₂
2K⁺ + CO₃²⁻ + 2H⁺ + SO₄²⁻ = 2K⁺ + SO₄²⁻ + H₂O + CO₂
CO₃²⁻ + 2H⁺ = H₂O + CO₂
Na₃PO₄ + 3AgNO₃ = Ag₃PO₄ ↓+ 3NaNO₃
3Na⁺ + PO₄³⁻ + 3Ag⁺ + 3NO₃⁻ = Ag₃PO₄ ↓+ 3Na⁺ + 3NO₃⁻
PO₄³⁻ + 3Ag⁺ = Ag₃PO₄ ↓
KOH + HCl = KCl + H₂O
K⁺ + OH⁻ + H⁺ + Cl⁻ = K⁺ + Cl⁻ + H₂O
OH⁻ + H⁺ = H₂O