P2: 21 Acids, Bases, and Buffers Flashcards
What is a Bronsted-Lowry acid?
A proton donor.
What is a Bronsted-Lowry base?
A proton acceptor.
What do acid-base equilibria involve?
The transfer of protons.
Why is a logarithmic scale, the pH scale, used as a measure of H+ concentration?
The concentration of H+ in aqueous solution covers a very wide range.
What is the equation for pH?
-log10[H+]
What is the equation for Kw?
Kw = [H+][OH-]
What does the value of Kw vary with?
Temperature.
What do weak acids and bases do in aqueous solution?
Dissociate only slightly.
What is Ka?
The dissociation constant for a weak acid.
What is the formula for pKa?
pKa = -log10Ka
What is Kw?
The ionic product of water.
What does a buffer solution do?
Maintains an approximately constant pH, despite dilution or addition of small amounts of acid or base.
What do acidic buffer solutions contain?
A weak acid and the salt of that weak acid.
What do basic buffer solutions contain?
A weak base and the salt of that weak base.
What are the applications of buffer solutions?
- shampoos
- biological washing powders
- biological buffer solutions in our bodies
Explain the action of acidic and basic buffers.
If the concentration of an ion increases, the equilibrium shifts the other direction to oppose the increase so the [H+] stays almost the same so the pH stays almost the same.
What is the formula for Ka?
[H+][A-] / [HA]
