pH and Buffers Flashcards
What is the hendersen Hasselbalch equation used to calculate?
PH
what is the Henderson hasselbalch equation?
pH=pKA+log (Conjugate base/acid)
What is an acid?
a substance that acts as a proton donor
What is a conjugate base?
a substance that acts as a proton acceptor
What is a reversible reaction
A reaction that works in both directions but favours one side more than the other
Explain acid-base reactions
when acid base reactions occur in an aqueous state the strongest acid will be revealed
What does KA represent?
The equilibrium constant
What is the midpoint?
when half of the bases have accepted a proton
Why is the pKA important at the midpoint?
The pKA at this point is the same as the pH
What is the endpoint?
When all the bases have accepted a proton
What is normally the intracellular pH?
7.4
What are the 3 main buffers?
- phosphate
- Histadine
- Bicarbonate
Why is histadine an important buffer?
- It is the only amino acid with a pKA value near 7.4
What is a buffer?
- A molecule that resists changes in pH
What is Cariogenesis?
The process of producing caries
What is the chemical formula for bicarbonate?
HCO3
What is the enamel pellicle?
The tooth biofilm
What happens in the buffering system that doesn’t happen during buffering in other parts of the body?
in saliva the protons are eliminated not just buffered
- this occurs as they are released into the environment through CO2 in exhalation
What is Le Chatelier’s Principle?
When the position of the equilibrium changes to minimise the effect of any imposed change in conditions
What is the common ion effect?
- By adding a common ion the weak acid or base is prevented from ionising as much
What is a common ion?
An ion present on both sides of an equilibrium reaction
