W8 Extraction

Question 1

requirement for forming a solution

Answer 1

energy released from solvent-solute interactions must be greater than energy used for solvent-solvent and solute-solute interactions

Question 2

what Is extraction

Answer 2

method to separate compounds or metal complexes based on their relative solubilities in two different immiscible liquids, usually water and an organic solvent

Question 3

definition of partition coefficient

Answer 3

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)

Question 4

When performing liquid-liquid extractions, what does shaking the separation funnel changes?

Answer 4

increases the rate at which partitioning reaches equilibrium

Question 5

how does extraction efficiency changes with pH when solute is an acid or base

Answer 5

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

Question 6

definition of distribution coefficient

Answer 6

used in place of partition coefficient K when dealing with a species that has more than one chemical form