Acids And Bases 3

Question 1

Acids

Answer 1

Substances that can donate a proton

Question 2

Bases

Answer 2

Substances that can accept an electron

Question 3

ionization of water

Answer 3

-water can partially ionize into H+ and OH- (which exists as H30+)
-ionization can be expressed as an equilibrium; H2- is always ~55.5M
Keq can be converted to the ionization constant of water Kw=10^-14
-pure water is neutral [H+]=[OH-]=10^-7

• if [H+]>[OH-] solution is acidic
• if [H+]

Question 4

pH scale

Answer 4

-pH = -log[H+]

Question 5

Weak acids and ionization

Answer 5

-proton dissociation from a weak acid produces its conjugate base
-Ka is the acid dissociation constant
Ka=[A-][H+]/[HA]

pKa=-log(Ka)

• lower pK value the stronger the acid
• higher pK value the weaker the acid

pH = pK + log[A-]/[HA]

Question 6

Henderson-Hasselbalch Eq

Answer 6

pH = pK + log[A-]/[HA]

• when pH=pK, [HA]=[A-]
• buffer region: resists pH change upon acid or base addition
• phosphate is an important cellular buffer due to its physiological

Question 7

Bicarbonate buffer system

Answer 7

• maintains blood and extracellular pH at 7.4

- works because dissolved CO2 is maintained low relative to HCO3- by equilibrium with gaseous CO2 in the lungs