ACID/BASE EQUILIBRIA Flashcards
What is an acid?
An acid is a proton (H+) donor
What is a base?
A base is a proton {H+) acceptor
What is Kw for water at room temperature?
Kw - [H+] [OH-] = 10E-14
Strong acids:
HCl
HBr
HClO4
HClO3
H2SO4
HNO3
Strong bases:
LiOH
NaOH
KOH
RbOH
CsOH
Ca(OH)2
Sr(OH)2
Ba(OH)2
How is K written for strong acids?
Very large
How is K writen for weak acids?
Ka
The larger the Ka, the stronger the base
How is K written for a weak base?
Kb
The larger the Kb the stronger the base
What is the formula for [H+]?
[H+] = √Ka(Ca)
What is the formula for [OH-]?
[OH-] = √Kb(Cb)
How are Ka and Kb of its conjugate base related?
The larger the Ka, the smaller the Kb of its conjugate base
What forms when acids and bases react and are neuralized?
Salts
What is a buffer?
A buffer is a solution that contains sustantial amounts of a compound in both its protonate and deprotonated forms, which male it resistant to changes in pH
How do you calculate pH of a buffer?
pH = pKa + log[A-/HA]
How do you calculate pOH of a buffer?
pOH = pKb + log[BH+/B]
What is a titration?
A titration is the procedure in which a strong acid or base of acccurate concentration is added stepwise in small amounts to incrementally neutralize the solution
What is an analyte?
An analyte is the “unknown” solution for which you would like to know either the concentration or K value of
What is a titrant?
A titrant is the “known” solution which has a percise and accurate concentration
What is the equivalence point?
The equivalence point is the point at which the number of moles of added base are equal to the number of moles of analyte solution
What is the half-equivalence point?
The half-equivalence point is the point at which half of the original analyte has been neutralized
How do you convert between Ka and Kb?
1E-14 = [Ka][Kb]
How do you convert Ka to pKa (of Kb to pKb)?
pKa = -log[Ka] (or pKb = -log[Kb])
What species dominates at the equivalence point?
100% A- (conjugate base to strong acid)
Explain what is happening at the half-equivalence point?
Moles HA = moles A-
What is the protonated state?
pH < pka
What is the deprotonated state?
pH > pKa
What is needed for an indicator to effectively indicate the endpoint of the titration?
pKa needs to be close to the pH of the equivalence point of the titration
