Terminale Spécialité Physique/chimie : Liste des chapitres
Chap10 : Équilibre acide-base
Exercices
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10.Eac3 : Couples et constantes d’acidité

Compléter le tableau ci-dessous.

Acide du couple Base du couple Expression de \(K_A\) Valeur de \(K_A\) Valeur de \(pK_A\)
  \(\ce{HCOO-}\)     \(\pu{3,8}\)
  \(\ce{CH3NH2}\)   \(\pu{2,5E-11}\)  
\(\ce{H3O+}\)       0
\(\ce{C2H5COOH}\)     \(\pu{1,3E-5}\)  
Afficher la correction
Acide du couple Base du couple Expression de \(K_A\) Valeur de \(K_A\) Valeur de \(pK_A\)
\(\ce{HCOOH}\) \(\ce{HCOO-}\) \(\dfrac{\ce{[HCOO-]_f\ce{[H3O+]_f}}}{\ce{[HCOO-]_f}}\) \(\pu{1,6E-5}\) \(\pu{3,8}\)
\(\ce{CH3NH3+}\) \(\ce{CH3NH2}\) \(\dfrac{\ce{[CH3NH2]_f\ce{[H3O+]_f}}}{\ce{[CH3NH3+]_f}}\) \(\pu{2,5E-11}\) \(\pu{10,6}\)
\(\ce{H3O+}\) \(\ce{H2O}\) \(\dfrac{1×\ce{[H3O+]_f}}{1×\ce{[H3O+]_f}} = 1\) \(\pu{1}\) 0
\(\ce{C2H5COOH}\) \(\ce{C2H5COO-}\) \(\dfrac{\ce{[CH2H5COO-]_f\ce{[H3O+]_f}}}{\ce{[C2H5COOH]_f}}\) \(\pu{1,3E-5}\) \(\pu{4,9}\)