Acids and bases Flashcards
What is a Bronsted-Lowry acid?
It is a proton donor.
What is a Bronsted-Lowry base?
It is a proton acceptor.
What is meant by the term ‘strong acid’?
It fully dissociates in water to give H+ ions.
What is meant by the term strong base?
It fully dissociates in water to give OH- ions.
What is meant by the term weak acid/ weak base?
It slightly dissociates in water
What is the equation for the ionic product of water?
Kw=[H+][OH-]
What is the value of the ionic product of water at 298K?
Kw= 1.00*10^-14 mol^2 dm^-6
Define the pH scale
It is a measure of the concentration of the hydrogen ion
pH = -log[H+]
Define Ka
It is the acid dissociation constant for weak acids
Ka=[H+][A-]/[HA]
Define pKa
pKa = -logKa
Define the equivalence point
The pH at which the number of moles of OH- added exactly equals the number of moles of H+ originally present.
What are the two common indicators used in titrations?
Methyl orange
Phenolphthalein
What are the pH range and colour change of methyl orange?
pH range- 3.2-4.4
Red in acid, Yellow in alkali
What are the pH range and colour change of phenolphthalein?
pH range- 8.2-10.00
Colourless in acid, pink in alkali
What is a buffer?
A solution that resists changes in pH when small amounts of acid or alkali are added or when it is diluted.
