Week 1: The Henderson-Hasselbalch Equation

Acidity and basicity are ways of measuring the concentration of protons in a solution--protons are acidic, so an acidic solution is characterized by having a high [H⁺]. One equation that is commonly used in biology and chemistry is the Henderson-Hasselbalch equation (which I primarily chose to write on because of its cool name). This equation relates the pH of a solution (the negative log of [H⁺]) with the chemical's acidity (pK_a--an inherent property of the chemical) and its concentrations in both its acidic ([HA]) and basic ([A^-]) forms: $$pH=pK_a+log(\frac{[A^-]}{[HA]})$$ If we imagine a solution of a chemical with a defined pK_a and a known ratio of $\frac{[A^-]}{[HA]}$, we can easily calculate the pH of that solution using this equation. This equation is especially useful in buffers--solutions whose pH's change very little even when strong acids or strong bases are added.


Sources:
https://en.wikipedia.org/wiki/Henderson%E2%80%93Hasselbalch_equation
https://en.wikipedia.org/wiki/Buffer_solution

Week 1: Introduction

Hi! My name is Kaelyn, and I'm a junior concentrating in Molecular and Cellular Biology (aka the best concentration). On top of that, I'm interested in pursuing Astrophysics as a secondary, which is why I'll be taking Astro 16. I had a great time in Astro 17 last semester, but am even more excited for this semester. As I have much more experience with the life sciences than I do physics, I'm especially excited to learn a bit more about astrochemistry and astrobiology. My ultimate goal is to go to medical school and become a surgeon, but after that I wouldn't turn down an astronaut job!