pH and Buffering

Question 1

How do buffers work?

Answer 1

They release H ions when the pH rises, and accept H ions when pH drops.

Question 2

What is the equation for pH?

Answer 2

pH = -log[H+]

Question 3

What is the equivalence point of a pH titration curve?

Answer 3

It is half way up the steep part of the graph and represents a point where all of the acid had dissociated into conjugate base

Question 4

What is the pH of half of the equivalence point equal to?

Answer 4

The pKa

Question 5

What is the pKa of a solution?

Answer 5

It is -log(ka) where ka is the dissociation constant

It is the point in a titration where the solution is half acid and half conjugate base

Question 6

What do the flat sections on a pH titration curve indicate?

Answer 6

Buffering

Question 7

State the Henderson hasslebach equation.

Answer 7

pH = pKa + log(cojagate base conc./acid conc.)

Question 8

What makes a good buffer?

Answer 8

A weak acid and its conjugate base

Question 9

When is a bufferer at its best?

Answer 9

Around its pKa

Question 10

What is the pKa of oxyhemoglobin?

Answer 10

6.8

Question 11

What is the pKa of deoxyhemoglobin?

Answer 11

7.8