chem terms for exam 2

  1. common ion effect
    lowering the solubiliy of a solid by putting it in a solution that already has one of the ions from the solid in it
  2. conjugate acid base pair
    2 substances related to ech othe by the transfer of a proton
  3. Kw
  4. pH
    the negative log of the concentration of hydronium ions in a solution;the pH scale is a compact way tospecify the acidity of a solution
  5. buffer
    a solution containing significant amount of both weak acid and its conjugate base that resist pH change by nuetralizing added acids or bases
  6. Henderson-Hasselbach equation
    • an equation used to easily calculate the pHof a buffer solution from the initial concentrations of the buffer solution assumingthe "x is small" approximation
    • pH=pKa+log [base]/[acid]
  7. complex ion
    an ion that contains a central metal ion bound to one or more ligands
  8. ligand
    a nuetral molecule or an ion that acts as a Lewis base with the central metal ion in a complex ion
  9. lewis base
    an atom,ion, or molecule that is an electron pair donor
  10. coordination compound
    a nuetral compound made when a complex ions combines with one or more counterions
  11. formation constant
    • (Kf)
    • the equilibrium constant associated with the reactionsfor the formation of the complex ion
  12. counterion
    ions of an opposite charge that arent acting as lgands(couterion + complex ion= coordination compound)
  13. coordination number
    the number of molecules or ions directly bound to the metal atom
  14. monodentate
    ligands that donate ony one electron pair to the central metal
  15. bidentate
    ligands that donate two electron pairs to the central metal atom
  16. polydentate
    ligands that donate more than one electron pair to the central metal
  17. crystal-field splitting
    the differenc ein enery btw the split dorbitals
  18. strong-field ligand
    the crystal field splitting is large
  19. weak-field ligand
    the crystal field splitting is small
  20. complementary color
    if a substance absorbs a color it will reflect the complementary color ex: if it absorbs green it will appear red
  21. diamgnetic
    the electrons are paired
  22. paramagnetic
    electrons are unpaired
  23. second law of thermodynamics
    for any spontaneous process, the entropy of the universe increases
  24. spontaneous reaction
    • a fair amount of products made for the amount of reactants used
    • doesnt mean fast just means it happens
    • it happens on its own
  25. enthalpy
    • the sum of its internal energy and the products of its pressure and volume
    • (delta H)
    • exothermis means enthalpy is negative
    • endothermic means enthalpy is positive
    • enthalpy is not enuf to predict how spontaneous must also consider entropy
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chem terms for exam 2