3.8 Acids and bases Flashcards
What is the Brownsted theory of acids?
Acids are proton donors
bases are proton acceptors
How do you number the acid base pairs?
Find LH acid pair 1
Find RH base pair 1
Find LH base pair 2
Find RH base pair 2
What does a KC value of 1 mean?
The system is at equilibrium
What does a KC value of more than or less than 1 mean?
More than= More on RHS
Less than= More on LHS
What is the Kw expression for water? (Ionic product of water)
Kw=[H+][OH-]
What is the equation for pH?
-Log10[H+]
What does an increase in temperature favour at equilibrium?
The endothermic side
What does an increase in pressure favour at equilibrium?
The side with less mols of gas
What is the expression for pKa?
-Log10[pH]
What is a buffer solution?
A mixture that minimises changes in pH with small additions of acid or alkali
What do buffer solutions contain?
The acid and its conjugate base
How does a buffer shift equilibrium when alkali is added?
RHS shift
alkali reacts with H+ and so it decrease
right to counteract change
How does a buffer shift equilibrium when acid is added?
LHS
reacts with base and so left to counteract
What is an equivalence point?
the point at which there is exactly enough base to neutralise the acid
What is the pH of solutions formed from weak acid salts?
greater than 7
