How can the sudden disappearance of a blue color become a precise chemical measurement? Sodium thiosulfate turns one of chemistry's most dramatic color changes into a quantitative endpoint.
What connects a chemistry titration, a rusty surface, a spinach leaf, and a kidney stone? The answer is a tiny two-carbon unit: oxalate.
How can a molecule with only two carbon atoms help take a giant protein apart? The secret is one sulfur atom—and its ability to open disulfide bonds.
BaCl2 and BaCl2·2H2O differ by only two water molecules. Why, then, do they have different CAS numbers—and when does that little bit of water actually matter?
Why would chemists intentionally make a pharmaceutical impurity? Because sometimes the molecule you don't want is exactly what you need to understand—and improve—the manufacturing process.
How do chemists install an acetyl group without actually starting with an acetyl group?
In chemistry, stronger isn't always better. Sodium cyanoborohydride became famous precisely because it is a milder reducing agent than sodium borohydride.
Some chemical reagents are building blocks. Others are tools.