pH, acids and bases Flashcards
week 2
define pH
-log10[H+]
define acidosis
pH is less than 7.35
define alkalosis
pH is more than 7.45
what is the normal range for physiological pH in the body?
7.35 - 7.45
define acid
molecules that tend to release protons
define base
molecules that accept protons
an acid is a proton …
donor
a base is a proton …
acceptor
define conjugate base
chemical formed upon ionisation of an acid
define conjugate acid
acid formed when a base and proton binds
the larger Ka is, the … the acid
stronger
the smaller pKa is, the … the acid
stronger
define pKa
the pH at which the acid is half dissociated into H+ and A-
define buffer
a substance that resists pH change on addition of acid or base
when do acids or bases act as buffers?
when the pH is close to their pKa (+/- 1 pH unit)
define buffering region
when there is roughly equal amounts of acid and base
what are the requirements of a buffer?
their pKa value must be close to the pH needed
must be biologically and chemically inert
what ions buffer blood?
phosphate (HPO42-) and bicarbonate (HCO3-)
define compensatory respiratory alkalosis
excess CO2 exhaled at the lungs to increase pH/reduce acidity
explain the importance of physiological buffers
examples
prevent large changes in the pH of bodily fluid
eg. phosphate and bicarbonate
define dissociation
loss of H+ ions
