Acids, bases and buffers Flashcards
what are Bronstead Lowry acids
proton donors
what do H+ ions form in water
hydroxonium ions
what are Bronsted Lowry bases
proton donors
what is called when an acid can donate more than one proton and give examples
polyprotic
nitric acid
sulphuric acid
phosphoric acid
acids react with bases to form _______ which are pH _____
salts pH
what is a conjugate pair linked by
transfer of a proton
any species that has gained a proton is a conjugate _____ and any species which has lost a proton is a conjugate ______
acid, base
when a strong acid or base is present the forward or backward reaction is favoured? and more ions are produced
forward
what is the equation for Kw
Kw= (H+)(OH-)
how do you calculate pH
pH= -log10 (H+)
how do you calculate conc. of H+ ions
= 10^-ph
monoprotic acids dissociate to produce one H+ ion for every acid molecule, this means that
conc of the acid= conc of H+ ions
diuretic acids dissociate to produce two H+ ions for every acid molecule this means that
conc of acid= 2 x conc of H+ ions
weak acids only dissociate slightly in aqueous solutions so what constant is used to work out their pH
Ka
what are the two assumptions made when calculating Ka of a weak acid
only a small amount of weak acid dissociates
(conc of weak acid at equilibrium)= (conc of weak cid at start)
the dissociation of acid is greater than the dissociation of water so all H+ ions come from acid
H+ conc= A-
what is the calculation for pKa
pKa= -log10Ka
what is the calculation for Ka using pKa
10^-pKa
when using a ph probe what must you do first
place in distilled water
draw titration curve for a strong acid and strong base
draw titration curve for strong acid weak base
draw titration curve for weak acid strong base
draw titration curve for weak acid weak base
what is the equivalence point on a titration curve
when the acid has been fully neutralised by the base
H+ conc= OH- conc
what must you look at on a titration curve when choosing a suitable indicator
the vertical part