C21 - Acids, bases and buffers Flashcards
What is a Bronsted-lowry acid?
It is a proton donor
What is a Bronsted-lowry base?
It is a proton acceptor
What is a monoprotic acid?
Releases 1 mole of H+ ions per mole of substances e.g. HCl or HNO3
What is a diprotic acid?
Releases 2 moles of H+ ions per mole of substances e.g. H2SO4
What is a triprotic acid?
Releases 3 moles of H+ ions per mole of substances e.g. H3PO4
What is the equation to work out the pH?
pH = -log10(H+)
What is the equation to work out the number of H+ ions?
(H+) = 10^-pH
How many decimal places is pH left to?
2 dp
Do weak acids fully dissociate H+ ions?
No
What is the equivalence point?
At the equivalence point in an acid-base titration, moles of base = moles of acid and the solution only contains salt and water
What is significant about the half equivalence point?
At this point (A-) and (HA) are equal so therefore Ka = (H+)
What is the role of buffer solutions?
Oppose changes in pH when small quantities of acid or base are added
What is in an acidic buffer?
Acidic buffer has a weak acid and a salt
What is in a basic buffer?
Acidic buffer has a weak acid and a salt