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In the original 1771 experiment, Scheele used a very simple setup consisting of a glass retort with a glass receiver (round-bottom flask). Yes, the glass was etched to some degree by the fumes, but it was not drastic enough to destroy the apparatus. From Anders Lennartson's The Chemical Works of Carl Wilhelm Scheele [1, p. 22]: 3.1 Publication 1. ...


34

Why was Avogadro's number chosen to be the value that it is? Your question implies that you already know that it was a choice rather than something derived from first principle. There are some numbers that are derived from first principles. In math, $\pi$ and $e$ are not a choice, but can be derived from their properties. In physics, the fine structure ...


27

Tryptophan For instance, is there a reason 'W' specifically was chosen for tryptophan (other than the fact that 'T' was taken)? Once you have assigned the other 19 amino acids, there are only 7 letters of the alphabet left: B, J, O, U, W, X, and Z. (Certainly not a nice Scrabble hand to have!) If one wants to use a letter found within the name of the amino ...


21

Neptunium (93) and plutonium (94) were so named because they followed uranium (92) on the periodic table. Uranium was named after Uranus. German chemist Martin Heinrich Klaproth discovered uranium in 1789, eight years after William Herschel discovered Uranus. At the time, uranium was the densest element known and Uranus was the farthest planet from the sun ...


21

The example that comes to mind is didymium, which turned out to be a mixture of praesodymium and neodymium. The term is still used, as far as I know, to refer to glass doped with a mixture of these lanthanides. This is discussed in one of the 'Chemistry in its element' podcast episodes. As it turns out, wikipedia has a category called 'Misidentified ...


20

The links provided below are to the website "Elementymology & Elements Multidict". It is a fascinating site with information on the discovery, naming and various other facts for each element. As the author (Peter van der Krogt) says, "I am not a chemist, but a (map) historian much interested in the origin of names". Enjoy! A nice piece on the ...


19

Sometimes it was a lucky accident, sometimes there was a lot of math and logic going in the designing experiments. The organic chemistry of that era, though, was a lot more applied and empirical than the physics of today. They usually weren't setting out to find the absolute laws-of-nature governing chemistry, they were just trying to make better dyes, ...


16

Asked and answered, but this is a good place to include other astronomically named elements: cerium named after the asteroid Ceres (or the Roman goddess of agriculture) helium from the Greek helios or "Sun" mercury OK, named after the Roman god, but so was the planet palladium named after the asteroid Pallas, discovered the year that Pd was first isolated ...


16

Some single letter codes that aren’t the amino acid’s starting letter actually make sense when viewed from certain angles. Here’s the list starting with the bloomin’ obvious: G — Glycine A — Alanine V — Valine L — Leucine I — Isoleucine P — Proline S — Serine T — Threonine C — Cysteine H — Histidine M — Methionine Some amino acids have a letter that ...


16

Please do not underestimate the scientists of 19th century. They were as creative, intelligent and perhaps more genuinely dedicated to science than the scientists of the 21st century. Spectroscopy was the tool of the trade to identify and verify that a given substance is not a mixture. The original reference which established that Didymium was a mixture is ...


15

(Will do more research into ammines come February.) Premise Ammonia is spelled with two 'm's. The more natural derivative of the word in a linguistic sense would also have the same number 'm's. Thus whichever predates the other, ammine complexes or amines, would claim the throne. In a structural sense, when awknowledgement of the first ammine complex came ...


14

Imagine a time when magnetic stirrers were unknown. You, or your lab assistant, would mix solutions in suitable glassware, shake manually, put it aside and then observe a change. An Erlenmeyer flask is much more suitable than a simple beaker the flat bottom gives it a stable stand on the bench the narrrow neck allows to hold and shake a large flask with ...


14

Based on research inspired by andselisk's answer, chemists stored it in glass vessels coated in wax (similar to the receiver setup Scheele used to prove the silicon dioxide precipitate was from the glassware itself. The fourth paragraph down in this blog post on The Chronicle Flask touches on it (emphasis mine): Where do you put something that eats ...


13

From the practical historical perspective chemists and physicists needed a number to use as a conversion factor from Daltons to grams to perform stoichiometric reactions. In the beginning, Dalton proposed to use the mass of the Hydrogen and assign it to a value of 1 Dalton without knowing how many grams correspond to 1 Dalton. Scales use grams, not daltons ...


12

The Periodic Table arranges elements in blocks as each type of orbital fills with electrons - $s,p,d,f,g,h$. Alkali metals and alkaline earths are $s$-block filling (but could be one $s$-block slot). $p$-block six electrons to fill are trelides, tetralides, pnticides, chalcogenides, halides, inert gases (but could be one $p$-block slot). Transition metal $...


12

(with thanks to @NilayGhosh, who provided the key source for much of this answer) Short answer: Potassium was called Potassium (and Sodium Sodium) by Humphry Davy, who first isolated both; it was then renamed Kalium in Germanic countries because of a previous naming proposal by Klaproth, who was the first to show that potassium carbonate and sodium ...


12

Modern day scientists rely on technology and advanced nuclear physics. But in absence of these advances, how were ancient scientists able to discover them? In many cases, they weren't - the ancient... maybe we can't call them scientists. Let's call them "natural philosophers." The ancient natural philosophers (up until about 1700) only knew about a handful ...


12

Structure elucidation via degradative studies and decomposition chemistry has sadly all but passed from the chemists' toolbox, but this was the method once used to determine molecular structures up until about half a century ago. One of my very favourite examples that I use to teach structure determination by NMR is the story of strychnine. Strychnine (below)...


12

Nitrogen was originally called 'azote' by Lavoisier. This name persists in many nitrogen containing species such as azide, hydrazine, diazonium etc. The '-ide' ending is the standard ending for anions of a single element such as carbide, oxide, sulfide etc.


12

First came the Arrhenius theory. It defines an acid as a species that dissociates to produce $\ce{H+}$ in solution, and a base as a species that dissociates to produce $\ce{OH-}$ in solution. (Examples: $\ce{HCl}$, $\ce{NaOH}$) Next came the Brønsted-Lowry theory, which expands the notion of acid and base. It defines an acid as a species that loses $\ce{H+}$...


11

This seems like a bit of a rhetorical question, so this isn't a terribly formal or authoritative answer, but anyhow - a lot of chemical nomenclature is like lava flow. It solidified and people just worked around it. The halogens are so named because they have a rich chemistry of ionic compounds (fluorine through iodine, anyhow). However, both the halogens ...


11

Created in FORTRAN by Carroll K. Johnson, of the Oak Ridge National Laboratory (ORNL), and first released in 1965, ORTEP (Oak Ridge Thermal-Ellipsoid Plot Program) rapidly became a favorite of crystallographers and protein crystallographers to produce illustrations of structures for conference presentations and publications. A key strength of ORTEP was its ...


11

One thing that was well known, even in the early days, was elemental analysis. It is Justus von Liebig’s contribution to have worked out the sum formulae of hundreds of natural compounds. This generally worked by combusting a given sample of a compound, capturing the vapours, absorbing the water with desiccants such as calcium chloride, absorbing carbon ...


11

See IUPAC-IUB Commission on Biochemical Nomenclature A One-Letter Notation for Amino Acid Sequences The Journal of Biological Chemistry Vol. 243, No. 13, pp. 3557-3559, 10 July 1968. : The possibility of using one-letter symbols was mentioned by Gamow and Ycas (2) in 1958. The idea was systematized by Šorm et al. (3) in 1961. It was used by this group ...


11

In 1978, the IUPAC Commission on the Nomenclature of Inorganic Chemistry decided that it would be necessary to have a systematic naming for the elements with atomic number greater than 100, even for those which had not been discovered. The recommendations are as follows: The name is derived directly from the atomic number of the element using the ...


10

First thing, they couldn't tell elements and compounds apart. See Dalton's list of elements with their symbols. Lime is right there--and it's not actually an element. Neither is Baryte(s). Soda and Potash probably refer to the oxides of Sodium and potassium, though terminology may have been different back then. In those days, elements were things that ...


10

Found a source here with some of the history and explanation, Named after Ytterby, a village in Sweden near Vauxholm. Yttria – earth containing yttrium – was discovered by Gadolin in 1794. Ytterby is the site of a quarry which yielded many unusual minerals containing rare earths and other elements. This small town, near Stockholm, bears the honor of giving ...


10

Please note that I haven't seen the sample myself! However, the Royal Institution claims that a bottle with the collidal gold solution is on display at Michael Faraday's Magnetic Laboratory (see bottle at the bottom of the image) in the museum of the Royal Institution. Update This might be nitpicking and English isn't my native language, but David ...


10

In pharmaceutical industries, $56\%$ of the drugs currently in use are chiral molecules and $88\%$ of the last ones are marketed as racemates (or racemic mixtures), consisting of an equimolar mixture of two enantiomers. More recently, drugs originally marketed as racemic mixtures are reintroduced using the active isomer. Examples include racemic citalopram (...


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