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Today is a special holiday—Mole Day. Mole Day is an informal holiday that originated among North American chemists, chemistry students, and chemistry enthusiasts. People celebrate this chemistry-specific festival between 6:02 AM and 6:02 PM on October 23rd. A mole is a common unit in chemistry, and one mole of a substance contains several basic particles equal to Avogadro's number. In the American date format, the celebration time of Mole Day is written as 6:02 10/23, which looks very similar to Avogadro's number 6.02×10²³, hence the birth of this holiday. Moreover, the word "mole" in English also refers to a "mole (animal)", so the mole is used as the mascot of the holiday. Many high schools in the United States, South Africa, Australia, Canada, and other places celebrate Mole Day, where various activities related to chemistry or moles are held to stimulate students' interest in chemistry.

The Julia olefination (also known as the Julia–Lythgoe olefination) is the chemical reaction used in organic chemistry of phenyl sulfones with aldehydes (or ketones ) to give alkenes (olefins) after alcohol functionalization and reductive elimination using sodium amalgam or SmI 2. The reaction is named after the French chemist Marc Julia.

When we touch iron or steel alloy railings and handles, we often smell a "metallic odor." Commonly, people believe this smell comes from the metal itself. In fact, this metallic smell comes from us! The lipid substances on our skin can form "lipid peroxides" through oxidation. When touching iron products, lipid peroxides undergo decomposition and reduction reactions catalyzed by ferrous ions, producing "1-octen-3-one (OEO)," which has a strong metal and mushroom-like odor. This is the main compound causing the "metallic smell." The olfactory threshold of 1-octen-3-one is 0.03-1.12 μg/m3, and it is volatile, so even at very low concentrations, we can clearly smell this odor. Moreover, the smell is more intense when more sweat is on the hands. When we touch coins or metal keys, we can smell the metallic flavor because the copper and zinc ions in these metal products can also trigger this reaction. Aluminum products hardly produce a metallic odor.

It stands for diethyl azodicarboxylate, an orange–red liquid that becomes yellow when diluted in a solvent. DEAD is a strong electron acceptor; it oxidizes iodide to molecular iodine, hydrazine to molecular nitrogen, alcohols to aldehydes, and thiols to disulfides. DEAD’s principal use is as a reagent in the Mitsunobu condensation reaction, and it participates in Michael and Diels–Alder reactions. Because it explodes when heated, it cannot be shipped in pure form. Instead, it is transported in solution or adsorbed onto plastic particles.