Acids Bases & Buffers

Question 1

What is the law of mass action?

Answer 1

A + B C + D

The rate (Vf) of the forward reaction is proportional to the product of  [A] and [B]
Vf = Kf[A][B]

The rate (Vr) of the reverse eaction is proportional to the product of [C] and [D]
Vr = Kr[C][D]

Question 2

Define pH

Answer 2

measure of acidity/ basicity

log[H+] + log[OH] = -14
pH + pOH = 14

solution is neutral if pH =pOH = 7

Question 3

Deinfe pKa

Answer 3

log { ([H+][A-])/[HA] }

measure of the strength of an acid or base

lower pKa = stronger acid
higher pKa = stronger base

Question 4

Whats is the Henderson-Hasselbalch equation for any given weak acid or base?

Answer 4

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

Question 5

What is normal blood pH?

Answer 5

arterial: 7.34-7.44
venous: 7.28-7.42

Question 6

What is normal blood pCO2?

Answer 6

40

Question 7

How do weak acids and bases work to buffer pH?

Answer 7

By resisting change in pH

• max capacity at 1:1
• speed bump

Question 8

What is the pH range of maximal buffering capacity?

Answer 8

[A-]/[HA] = 0.1-10

Question 9

What is the H-H equation for the bicarbonate system?

Answer 9

pH = 6.1 + log[HCO3-]/0.3pCO2

Question 10

What are the clinical presentations of a change in CO2 levels?

Answer 10

respiratory alkalosis (decrease in CO2)
respiratory acidosis (increase in CO2)

Question 11

What is the clinical presentation of a change in HCO3- levels?

Answer 11

metabolic alkakosis (increase bicarb)
metabolic acidosis (decreased bicarb)