Acids, bases and Kw Flashcards
What are bronsted-lowry acids?
Proton donors
What are bronsted-lowry bases?
Proton acceptors
What does BAAD stand for?
Base
Acceptor
Acid
Donor
What do strong acids do in water?
Completely dissociate
What do weak acids do in water?
Partly dissociate
What is an example of a strong acid dissociating?
HCl -> H+ + Cl-
What is an example of a weak acid dissociating?
CH3COOH CH3COO- + H+
What do strong bases do in water?
Almost completely ionise
What do weak bases do in water?
Partially ionise
What is an example of a weak base ionising?
NH3 + H2O NH4+ + OH-
What is an example of a strong base ionising?
NaOH Na+ + OH-
Where does the equilibrium lie with strong acids and bases in water?
Far right
Where does the equilibrium lie with weak acids and bases in water?
Far left
Where does an acid put its protons?
Donates them to a base
What is the equation for the ionic product of water?
Kw = [H+][OH-]
What is the equation for the ionic product of pure water?
Kw = [H+]²
Why is the equation for the ionic product of pure water different to the ionic product of water?
In pure water, there is always one H+ ion for every OH- ion
Why doesn’t the expression for Kw include the concentration of water?
The concentration of H2O is so high compared to the concentration of [H+] and [OH-] and therefore it is effectively constant and doesn’t need to be included in the expression
Why does the value of Kw increase with temperature increasing?
Dissociation is endothermic so therefore the equilibrium moves to the right hand side to absorb heat
