Calcolatore Costante di Equilibrio
Calcola la costante di equilibrio di una reazione chimica reversibile.
Estimated ΔH
-818.0 kJ/mol
Estimated ΔH vs Total Energy of Bonds Broken
Formula
## Bond Energy Estimation of ΔH ### Formula **ΔH ≈ Σ(bonds broken) − Σ(bonds formed)** Where: - **Bonds broken** = energy required to break all bonds in reactants (positive, endothermic) - **Bonds formed** = energy released forming all bonds in products (positive values) Breaking bonds requires energy; forming bonds releases energy. If more energy is released than absorbed, ΔH is negative (exothermic).
Esempio Risolto
Combustion of CH₄: bonds broken = 4(C-H) + 2(O=O) = 4(413) + 2(498) = 2648 kJ; bonds formed = 2(C=O) + 4(O-H) = 2(805) + 4(464) = 3466 kJ.
- 01ΔH = Σ(bonds broken) - Σ(bonds formed)
- 02ΔH = 2648 - 3466
- 03ΔH = -818 kJ/mol (exothermic)
Domande Frequenti
How accurate is the bond energy method?
It provides estimates, typically within 5-10% of experimental values. Bond energies are averages and vary depending on molecular environment.
Where do I find bond energy values?
Standard tables list average bond dissociation energies. Common values: C-H = 413, O-H = 464, C=O = 805, O=O = 498 kJ/mol.
Why are bond energies positive?
Bond energies represent the energy needed to break a bond (endothermic process). Forming the same bond releases that energy.
Impara