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Questions tagged [terminology]

For questions relating to terminology and naming conventions in chemistry.

This tag should be applied to questions regarding how chemists refer to a specific notion. Often it's about what the technical word for a concept or technical application is, or how one should technically use a scientific term.

For questions about the naming of compounds and elements use instead.

Canonical Answers

542 questions
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What is the definition of of 'compound', 'mixture', 'element' and 'molecule'?

I am looking for the precise definitions, as I am very confused as to what they are exactly because although I mostly understand what they mean, I have encountered some conflicting definitions that confused me. As it stands, this is what I…
Sophia
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What is parachemistry? What does a parachemist do?

I was reading the Washington Post article An atomic town revels in its nuclear past as tunnel collapse raises contamination concerns and came across a quote from someone who was said to have been a "parachemist" at the Hanford nuclear facility in…
uhoh
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What kind of chemical used in a chromatography run could be denoted with the letters D.H.?

A fellow translator is having trouble translating (into Russian) the mysterious D.H. abbreviation in the following passage: Slight variations of the ratio of the mobile phase constituents or adjustments of the mobile phase flow-rate can be made…
CowperKettle
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Quick and simple explanation of molar mass, molecular mass and atomic mass

As a physics student, I hardly deal with such quantities and when I do, I blunder through. I think it’s a good time to be given a good explanation for these since I’m in a class of Nuclear physics. I have tried googling but it seems that some…
physkid
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Should one pronounce “periodic” the same in “periodic acid” and “periodic table”?

In “periodic table”, the adjective is related to the noun period, and comes from Ancient Greek περίοδος through French périodique. In “periodic acid”, it is formed from the prefix per- and iodic (like peroxide and permanganate). Wiktionary lists…
F'x
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Is there a name for the opposite reaction to the dissolution?

When atmospheric $\ce{CO2}$ reacts with water to form $\ce{H2CO3}$, this is called dissolution, isn't it? What term would you use for the opposite reaction when it occurs at atmospheric pressure (e.g. due to temperature change)? For a solid it would…
radouxju
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What is a "formal" dimer?

I was researching for this question and I noticed the term "formal dimer": Hyponitrous acid is a chemical compound with formula $\ce{H2N2O2}$ or $\ce{HON=NOH}$. It is an isomer of nitramide, $\ce{H2N−NO2}$; and a formal dimer of azanone,…
Nilay Ghosh
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How to pronounce G°?

To denote standard state like enthalpy of formation in standard state, or change in Gibbs free energy in standard state, we use a degree-like symbol above the $G$ as in $\Delta G^0$. How should I refer to this superscript in spoken language?
thephysicist
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Meaning of the Term "Heavy Metals" in CofA?

I've always wondered, what is the meaning of the following terms on a certificate of analysis: "Heavy Metals" "Heavy Metals (as Pb)" What exactly is comprised in "heavy metals", "heavy metals (as Pb)" and what is excluded from each? What is the…
Hans
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Why is introductory chemistry so non-rigorous?

In introductory chemistry books, courses, ... Many "definitions" contain words like: typically, most, often, likely, generally. I read since questions on this site mentioning different definitions of same concept in different books. I just read…
foobar
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What does it mean when "a gas is dilute in CO₂"?

I'm reading an article about carbon sequestration, and I came across a strange phrase: "The flue gas is dilute in $\ce{CO2}$". I can't quite ascertain its meaning from the context. I think it means that the $\ce{CO2}$ is in low concentration in…
Paul
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What is "ölsaurem Alkali"

I read a technical German book that refers to "ölsaurem Alkali" which apparently means "oleic acid alkali". How could it be both an acid and an alkali?
Shaka Boom
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What is the adverb for a "hydrogen bond"?

I am looking for some opinions concerning the terminology around hydrogen bonds. Other types of bonds can be expressed as an adjective: "The atoms are bonded covalently." or (though less common) "(...) are bonded ionically.". Sometimes the sentence…
Yoda
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What is a "lower organic acid"?

From the "Technical guide for the elaboration of monographs" by EDQM, edition 7, 2015, page 25: Where the counter-ion of an active substance is formed from a lower organic acid, a test for related substances of the organic moiety is usually not…
CowperKettle
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What is the name for a reaction with a solid product rising from its container?

The reaction between sugar and sulfuric acid is well known to produce a solid column of rising carbon which may leave its container. A very similar rising column may also be produced from high temperature pyrolysis of certain organic substrates.…
Agriculturist
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