Acids and bases Flashcards
What is a Brønsted–Lowry acid and base?
Acid - proton donor
Base - proton acceptor
What does acid-base equilibria involve?
The transfer of protons.
What is the formula for pH?
pH = –log10[H+]
What makes a solution acidic?
Hydroxonium ions, H3O+ but H+ is usually written
What happens when water and acid mix?
H+ ions are released
What happens when water and base mix?
H+ ions react to form OH- ions which make a solution basic
What is the difference between:
- Strong and weak base
- Strong and weak acid
Strong acid - Ionises completely
Weak acid - partially ionises
Strong base - Ionises completely
Weak base - partially ionises
What does water dissociate into? Give the equation
Hydroxide and hydroxonium ions:
2H2O = H3O+ + OH-
OR
H2O = OH- + H+
What is the Kw equation and why is Kc not used?
Kw = [H+] [OH-]
Water dissociates very weakly into the ions hence we assume the concentration of water has a constant value. By multiplying Kc and [H2O] we get Kw which is mol2dm-6
What is the value of Kw?
1.00 x 10-14 mol2dm-6
What is Kw when referring to pure water?
Kw = [H+]2
What is the concentration like in pure water of H+ and OH-?
[H+] = [OH-]
What happens to the value of Kw if temperature increases and why?
Kw also increases because equilibrium is endothermic in the forward direction hence equilibrium shifts to the RHS to minimise temperature increase.
What is the equation used to calculate [H+] using pH?
10-pH
What are monoprotic acids? Give examples.
Acids that dissociate to produce 1 H+ ion for every acid molecule therefore [acid] = [H+]
- HCl and HNO3
