Unit 3 Flashcards
(28 cards)
titration
-the slow addition of one solution of a known concentration (called a titrant) to a known volume of another solution of unknown concentration
-acid/analyte is unknown, but the base/titrant is known, so by finding equivalence point, you can deduce amount of acid
indicator
-typically a weak acid that has different colors in dissociated and undissociated states
-changes colors as equivalence point
equivalence point
-point where the acid/base has been completely neutralized
-moles of acid and moles of base are equal
-determined through analyzing titration graph
End point
-point of titration when indicator changes color
-visible marker
-pH = pKin
Kin
-indicator constant
-Kin = [H3O][In-] / [HIn]
indicator equilibrium
-HIN(indicator) + H2O -> H3O+ + In-
pKIn
-pH - pKin = log([In-]/[HIn])
-similar to hendersson hasselbach
-when pH < pKin (acidic), it is initial color (color A)
-when pH = pKin, it is mixture (color A + B)
-when pH > pKin (basic), it is final color (color B)
titrant
-strong acid/base (typically base)
-known value, added to analyte
-analyte
-can be strong or weak acid/base (typically acid)
-unknown value, titrant is added to analyte
Strong acid and strong base
-Start: calculate pH by M of H3O (moles/L), usually equal to M of solution added
-Half: moles of H3O - moles of OH = new moles of H3O, then calculate pH from new M of H3O
-Eq: pH = 7
-past eq: calculate pH using M of OH (moles/L)
Weak acid and strong base
-start: use ICE table to find M of H3O and then pH
-half: usually equal to pKa, find M of OH added and then plug in values into hendersson hasselbach
-eq: number of moles of acid and base are equal, find pH by finding M of OH created by hydrolysis of base and Kb
-past eq: M of OH (moles/L)
monoprotic acid
-an acid capable of donating at most one hydrogen ion per molecule
polyprotic acid
-an acid capable of donating more than one hydrogen ion per molecule
-pH is calculated by filling out ICE table for each respective reaction (donation of H to H2O) and adding M of H3O produced to get pH
-ex. H2S (H2S and HS- can both be an acids)
-has twice the neutralization power of monoprotic acid
amphiprotic anion/salt
-a salt whose anion can serve as both a weak acid and a weak base
-pH = 1/2 (pKa1 + pKa2)
-ex. NaHS, HS can be acid or base
Saturated solution
-a solution in equilibrium with a solid solute
Supersaturated solution
-describes a solution that temporarily contains more solute than the equilibrium quantity
-will return by precipitating solid out of solution
Solvate
-process of surrounding solute molecules with solvent molecules
Solubility
-amount of solute that dissolves in a fixed volume of a given solvent at a given temp
-depends on temp and pH
Insoluble
ionic compound with solubility < 0.1 g/L
Slightly soluble
ionic compounds with solubilities between 0.1-10 g/L
Soluble
ionic compounds with solubilities >10 g/L
Ksp
-solubility product
-the equilibrium constant for the dissolution of a slightly soluble salt
-Ksp = [A+][B-] (when AB -> A+ + B-)
Molar solubility (S)
-S^2 = Ksp
-how many g of a salt dissolve per liter of water
-turned into gram solubility by multiplying S by molar mass of salt
Q
-reaction quotient
-Q = [A+][B-] (before any reaction occurs)
-predicts whether a precipitate will form when two solutions are mixed
-Q< Ksp, no precipitate will form
-Q> Ksp, precipitate will form until Q has reached Ksp
