P2: 21 Acids, Bases, and Buffers

Question 1

What is a Bronsted-Lowry acid?

Answer 1

A proton donor.

Question 2

What is a Bronsted-Lowry base?

Answer 2

A proton acceptor.

Question 3

What do acid-base equilibria involve?

Answer 3

The transfer of protons.

Question 4

Why is a logarithmic scale, the pH scale, used as a measure of H+ concentration?

Answer 4

The concentration of H+ in aqueous solution covers a very wide range.

Question 5

What is the equation for pH?

Answer 5

-log10[H+]

Question 6

What is the equation for Kw?

Answer 6

Kw = [H+][OH-]

Question 7

What does the value of Kw vary with?

Answer 7

Temperature.

Question 8

What do weak acids and bases do in aqueous solution?

Answer 8

Dissociate only slightly.

Question 9

What is Ka?

Answer 9

The dissociation constant for a weak acid.

Question 10

What is the formula for pKa?

Answer 10

pKa = -log10Ka

Question 11

What is Kw?

Answer 11

The ionic product of water.

Question 12

What does a buffer solution do?

Answer 12

Maintains an approximately constant pH, despite dilution or addition of small amounts of acid or base.

Question 13

What do acidic buffer solutions contain?

Answer 13

A weak acid and the salt of that weak acid.

Question 14

What do basic buffer solutions contain?

Answer 14

A weak base and the salt of that weak base.

Question 15

What are the applications of buffer solutions?

Answer 15

• shampoos
• biological washing powders
• biological buffer solutions in our bodies

Question 16

Explain the action of acidic and basic buffers.

Answer 16

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.

Question 17

What is the formula for Ka?

Answer 17

[H+][A-] / [HA]