Chapter 20 - Acids, Bases, and pH Flashcards
Define Brønsted-Lowry acid.
Proton donor
Define Brønsted-Lowry base.
Proton acceptor
What is a conjugate acid-base pair?
2 species that can be interconverted by a transfer of a proton.
In the dissociation of HCl to H+ and Cl-, identify the conjugate acid and base.
HCl(aq) —> H+(aq) + Cl-(aq)
HCl releases a proton so it is a conjugate acid.
Cl- accepts a proton so it is a conjugate base.
When water is the base, what is formed?
H3O+ Hydronium ion
What do monobasic, dibasic and tribasic refer to?
The number of hydrogen ions in an acid that can be replaced per molecule in an acid-base reaction.
What is the relationship between pH and concentration of H+ ions.
Low value of H+ = high pH
High value of H+ = low pH
What is the equation for working out pH from H+?
pH = -log x [H+(aq)]
What is the equation for working out H+ from pH?
[H+(aq)] = 10^−pH
How is pH calculated for a strong acid?
Assume it fully dissociates, so [H+(aq)] = [HA]
How is the new pH calculated for a strong acid on dilution?
Work out the change in concentration of [HA], and therefore [H+(aq)], and then plug it back in to:
pH = -log[H+(aq)]
What are the 2 approximations for calculating pH of a weak acid?
That dissociation of water is negligible.
That concentration of acid is much greater than the H+ concentration at equilibrium.
