Acids, Bases, and Buffers Flashcards
Acids
Proton donors
Bases
Proton acceptors
Monotropic Acid
Can donate one mole of protons per mole of acid
e.g. HCl
Diprotic Acids
Can donate two moles of protons per mole of acid
e.g. H2SO4
Strong acids
Dissociate completely in water
Strong bases
Ionise completely in water
e.g. NaOH and KOH
Weak acids
Dissociate weakly in water
Weak bases
Ionise weakly in water
Water can act as either:
Acid- donates proton
Base- accepts proton
Water dissociates into:
Hydroxonium ions H3O+
Hydroxide ions OH-
Ionic product of water
Kw = [H+] [OH-]
Effect of increasing temperature on Kw
Kw increases
pH decreases
Equilibrium moves to the right
pH scale
Measure of H+ present in a solution
pH
-log[H+]
[H+]
10^-pH
Weak acids and Weak bases in aqueous solution
Dissociate slightly
Concentration
Amount of acid in moles per cubic meter (mol dm-3)
Strength of an Acid
Extent to which it ionises
Acid dissociation constant
Ka = [H+] ^2 / [HA]
pKa
pKa = - log(Ka)
Ka
10^ -pKa
Equivalence Point
Colour change when mixing two solutions in equal proportion (vertical line) neutralisation occurs here
Methyl Orange
Red ——-> Yellow
Colour change: 3.1 - 4.4
Phenolphthalein
Colourless —–> Pink
Colour change: 8.3 - 10