Dear Students, I hope you all had fun learning about chromatography this week! It was great to see everyone successfully separate spinach pigments using column chromatography. Some of you had trouble achieving good separation on the TLC plates. Please don't worry: we will not be grading based on your Rf values or how well your pigments separated. Instead, I want you to focus on understanding the theory behind chromatography: What are intermolecular interactions? How does solv

Acid base chemistry is the quiet engine behind organic reactions. Before a nucleophile attacks, before a leaving group leaves, before a carbon-carbon bond forms, a proton often moves first. If that proton transfer is favorable, the rest of the mechanism may work. If it is not, the reaction may stall. The best shortcut for predicting these moves is pKa. A pKa value tells how strongly a compound wants to give up a proton. Low pKa means a strong acid. High pKa means a weak acid.

A solid can look clean and still carry impurities trapped between its crystals. Recrystallization fixes that by dissolving the material under the right conditions, then letting it form cleaner crystals as it returns to solid form. It is one of the most common purification techniques in chemistry because it uses a simple idea: a compound and its impurities often dissolve differently at different temperatures or in different solvents. If you choose the solvent well, the target

Distillation is one of the oldest separation methods, but it is still at the center of modern fuel production, chemical manufacturing, food processing, water treatment, and laboratory work. The basic idea is simple: heat a mixture, let the more volatile component turn into vapor first, then cool that vapor back into liquid. The method works because different substances boil at different temperatures. Yet not every mixture behaves the same way. Some liquids have very close boi