Acids bases and buffers

Question 1

What acid is formed from glucose during anaerobic respiration?

Answer 1

Lactic acid

Question 2

What acid is formed when CO2 dissolves?

Answer 2

Carbonic acid

Question 3

What happens to hydroxyapatite when the concentration of H+ ions increases and dissociation equation moves to the right?

Answer 3

The solubility of hydroxyapatite is increased - promotes demineralisation

Question 4

What helps remineralise teeth after meals?

Answer 4

Milk

Question 5

What is intrinsic erosion?

Answer 5

Erosion of teeth from stomach acids

Question 6

What is extrinsic erosion?

Answer 6

Erosion of the teeth from acids originating outside the mouth

Question 7

Other than citric acid, what agents do acidic fruit juices contain, that contribute to the erosion of the teeth?

Answer 7

Chelating agents

Question 8

At what point would a buffer be at its optimal capacity (3 things)?

Answer 8

• [acid] = [base]
• buffer is 50% dissociation
• pKa = pH

Question 9

What is the optimal buffering capacity for bicarbonate?

Answer 9

pKa = 6.37

Question 10

Why is bicarbonate the optimal buffer for saliva?

Answer 10

Because its optimal buffering capacity is 6.37pKa which is very similar to the pH of saliva so it works to resist changes in pH at this pH (6.7)

Question 11

Why is phosphate a very good buffer?

Answer 11

It has 3 optimal pKa values. It also works +or- 1 pKa, so encompasses the whole pH scale

Question 12

What buffer enhances the buffering capacity of bicarbonate?

Answer 12

Phosphate

Question 13

How many equivalence points does phosphate have?

Answer 13

3 (three points of inflexion)