W8 Extraction Flashcards
requirement for forming a solution
energy released from solvent-solute interactions must be greater than energy used for solvent-solvent and solute-solute interactions
what Is extraction
method to separate compounds or metal complexes based on their relative solubilities in two different immiscible liquids, usually water and an organic solvent
definition of partition coefficient
the ratio of concentrations of a compound in a mixture of two immiscible solvents
K = conc of solute in phase 1 / conc of solute in phase 2
phase 1: solvent that solute is initially dissolved in (bottom layer)
phase 2: extraction solvent (top layer)
When performing liquid-liquid extractions, what does shaking the separation funnel changes?
increases the rate at which partitioning reaches equilibrium
how does extraction efficiency changes with pH when solute is an acid or base
acidic solutes: put in higher pH > more deprotonated > more soluble in aqueous layer > extraction efficiency increases
basic solutes: put in lower pH > more protonated > more soluble in aqueous layer > extraction efficiency increases
definition of distribution coefficient
used in place of partition coefficient K when dealing with a species that has more than one chemical form