Other Equilibria - Chem Exam 3

“insoluble” salt

less than 0.01 mol dissolves in 1 liter of solution

K_sp =

[A^y+]^x * [B^x-]^y

Relative solubilities can be deduced by comparing K_sp only if

the salts have the same cation to anion ratio

smaller K_sp

less soluble salt

A_xB_y (s)

xA^y+ (aq) + yB^x- (aq)

Q = K_sp

at equilibrium, saturated

Q < K_sp

too few products

Q > K_sp

too many products

common ion effect

when an ionic compound is dissolved in water and a new soluble salt is added that contains one of the ions that the ionic compound also has, the solution creates a precipitate (forcing the original ionic compound back together) because the solution ‘overfilled’ with that one ion

common ion, the salt with the lowest solubility

precipitates first (assuming equal concentrations)

lewis acid

accepts electron pair

lewis base

donates electron pair

are metal cations lewis acids or bases

acids, accept electron pairs from ligands

ligands

molecules/ions with free electron pairs that act as bases

ligand + metal cation

coordinate complex

amphoteric

something can act as an acid or a base, can be used with B-L or lewis

amphiprotic

something can accept or donate H+, only applies to B-L

complex ions

metal cation bound to ions/molecules with e- pairs

formation constant Kf

measures how strongly a ligand binds to a metal cation to form a coordinate complex

Kf =

[complex ion] / ([metal cation][ligand])

low solubility salts dissolve better when in

solutions containing relevant ligands

insoluble salts whose anion is a base

dissolve in strong acids