Aqueous Equilibria & pH Flashcards
What is the concentration of [OH-] and [H3O+] due to the self ionisation of water at 298K?
1x10^-7 mol L-1
What is the Arrhenius definition of an acid?
A substance that, when dissolved in water, increases the conc of hydronium ions
What is the Arrhenius definition of a base?
A substance that, when dissolved in water, increases the conc of hydroxide ions
What is a limitation of the Arrhenius concept of acids and bases?
It only talks about OH- as the source of basic character
What is the Bronsted-Lowry definition of an acid?
A species that donates a proton in a proton transfer reaction
What is the Bronsted-Lowry definition of a base?
A species that gains a proton in a proton transfer reaction
How can you identify Bronsted-Lowry conjugate base pairs in a reaction
Two species in a reaction which differ by a H+ ion
What is the Lewis definition of an acid?
A species that can form a covalent bond by accepting an electron pair form another species
What is the Lewis definition of a base?
A species that can form a covalent bond by donating an electron pair to another species
What is a monoprotic acid?
An acid that will produce only one H+ ion upon dissociation
What is a polyprotic acid?
An acid that produce more than one H+ ion upon dissociation
What is the composition of an acid buffer?
Weak acid + salt of this weak acid
What is the composition of a basic buffer?
Weak base + salt of this weak base
What relative concentrations do you want of the salt and acid to form an acid buffer?
Conc of salt should be 1.25x greater than the acid.
E.g. 0.5 mol L-1 of salt, 0.4 mol L-1 acid
What is Le Chatelier’s principle?
The concentrations of reactants and products in an equilibrium mixture will alter so as to counteract any changes in temperature, pressure or concentration
