Topic 18 Flashcards
What is a lewis acid?
Electron pair acceptor
What is a lewis base?
Electron pair donor
What is an electrophile?
A substance that accepts a lone pair of electrons like a lewis acid
What is a nucleophile?
A substance that donates a lone pair of electrons
What is the difference between a BL acid and a lewis acid??
A lewis acid accepts electrons whereas a BL acid donates protons
What is Ka?
The acid dissociation constant
What is Kb?
The base dissociation constant
What is one of the formulas for Ka?
Ka = (H+)2/ HA
What does the magnitude of Ka tell you?
- The extent of dissociation of the acid
- increase in Ka= increase in dissociation = the stronger the acid
What does the magnitude of Kb tell us?
- The magnitude of dissociation of the base
- The higher the Kb the higher the dissociation the stronger the base
What is one of the formulas for Kb?
Kb = (OH)2/HA
What is Kw?
The ionic product constant of water
1X10-14
What is the formula for Kw?
Kw = Ka X Kb Kw = ( H+)(OH-)
Relationship between Ka and pKa?
Ka = 10-pKa pKa = - log ( Ka)
Relationship between Ka and pKa?
Ka = 10-pKa pKa = - log ( Ka)
What happens to the pKA value when Ka is increases?
pKA decreases
Is Kw temperature dependent?
Yes
Write the equations for the dissociation of water
H20 = H+ + OH-
Draw the pH curve for a strong acid strong base reaction
Draw the pH curve for a weak acid and strong base
Draw the pH curve for a strong acid and weak base
What is the equivalence point?
When equivalent amounts of acids and bases have reacted
- and the solution only contains salt and wate
- pH depends on the salt
What is the buffer region?
When small amounts of acid and bases are added whih resists a pH change
What is the half equivalence point?
When half the acid has been neutralised by the base and is converted into salt
What are acid base indicators?
They are weak acids or bases in which the undissociated and the dissociated forms have different colours
