Acid-base reactions Flashcards
What is a bronsted - lowry acid
a proton donor e.g., NH4+, HCl, CH3COOH
What is a bronsted-lowry base
proton acceptor e.g., NH3, OH-, CH3COO-
What is the mass action law
the rate of any chemical reaction is proportional to the product of the masses of the reacting substances, with each mass raised to a power equal to the coefficient that occurs in the chemical equation
How to use mass action law to calculate k
k = [A][B]/[C][D]
Solubility reaction example
HgS(s) <-> Hg2+(aq) + S2- (aq)
Acid-base reaction example
CH3COOH +H2O <-> H3O+ + CH3COO-
Redox reaction example
Zn <-> Zn2+ + 2e-
Partitioning reaction example
FeCl3(aq) <-> FeCl3 (org)
What is the LeChatelier principle
when a change is imposed in equilibrium, equilibrium will shift to oppose the change
What are conjugate acid-base pairs
transfer of a proton between 2 species changes if the compound is an acid or a base e.g. NH4+ and NH3
What is the ionic product of water
[H+][OH-} 1x10^-14
What does a strong acid usually react with
a weak base
Kw formula
Ka x Kb
pKw formula
pKa + pKb = 14
strong base pH formula
pH = 14 - pOH = 14 + log c0
pH formula of a weak conjugate acid
pH = 1/2(14-pKb)-1/2(lo(c0))
What is the ion product of water
[H3O+][OH-] = 10^-14
pOH calculations for a weak base
1/2pKb - 1/2logc0
How to calculate reaction involving a strong acid/base
there is no effect the pH = 7
How to calculate the pH of a reaction involving strong acid/weak base
pH = 7-1/2pKb - 1/2 log(c0)
How to calculate the pH of a reaction involving a weak acid/strong base
pH = 7 + 1/2pKa + 1/2 log(c0)
Ampholyte pH calculation
(pKa1+ pKa2)/2
What are the different types of ampholytes
salts of weak acid and weak bases, hydrogen salts or di/triprotic acids, compounds with acid and base functional group
What are buffers
solution of a weak acid or base and its conjugate acid/base
pH of buffers formula
pH = pKa + log([salt]/[acid])
[H3O+] formula
[H3O+] = Ka ([acid]/[salt])
How to calculate pKa from a buffer curve
When half added the base is added, the pH at that volume is equal to pKa
What is the end point in a titration
the point where the indicator changes colour (verticle section)
excess base on a buffer curve
pH = 14 - pOH = 14 - log[B]
pH at end point formula
7 + 1/2pKa = 1/2 log[A-]0
pH at the turning point formula
(pKa1+pKa2)/2
