Lecture 2 pH and Buffers Flashcards
What is the Henderson-Hasselbalch equation?
pH = pKa + log([A⁻]/[HA])
What is the Henderson-Hasselbalch equation used for?
to calculate pH or concentration of buffering species.
what does pH represent?
measures how acidic or basic a solution is.
what is the formula for pH including H+?
pH = -log[H⁺]
what does a lower pH mean in terms of protons?
there are more protons
what does pKa represent?
pKa measures the strength of an acid.
what does a low pKa mean?
strong acid
what is the formula to find the pKa including ka?
pKa = -log(Ka)
What is a buffer?
a mixture of weak acids and bases that resist pH changes
when do buffers work best?
+/- 1 pH unit around its pKa.
What are common pH environments in the body? (4)
Blood pH: 7.4
Stomach pH: 1.5-3.5
Cytoplasm: 7.2-7.8
Mitochondria: 7.8
How does the bicarbonate buffer system work in blood? (2)
neutralizes excess H⁺ to keep blood pH at 7.4.
CO₂ is exhaled to remove H⁺ and regulate pH.
What are tips to choose a buffer for an experiment? (2)
Pick a buffer with a pKa close to your desired pH.
Ensure the buffer is chemically stable and doesn’t interfere with your experiment.
how does pH affect proteins?
pH affects the ionization of functional groups, impacting protein structure and function.
