Questions tagged [terminology]

For questions regarding how something is referred to.

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What is the term for passing an eluate back through an adsorption column?

In my experiment I am passing a solution through an adsorption column, collecting the eluate, then passing the eluate back through the same column. Is there a concise term which describes this ...
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3answers
115 views

Is there a difference between dipole and dipole moment?

I’m confused as to whether both terms “dipole” and “dipole moment” are the same or different, does the moment have something to do with the molecular geometry? I know the vectors of the charges cancel ...
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What is a molecule’s smallest set of smallest rings?

It is been a while since I've studied chemistry. Now, I am reading the documentation of RDKit, where they mention the expression "smallest set of smallest rings" (SSSRs). I understand that a ring is a ...
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Learning chemistry in a new language [closed]

I'm from Slovakia, 16 and like chemistry a lot. I want to pursue it in the future but there aren't any good universities here where you can get a Ph.D. in chemistry so I want to go abroad, preferably ...
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Can a protein complex be a machine? [closed]

Discussing an article with friends we began discussing whether a protein complex that punches holes in cells (membrane attack complex) would be considered a machine. Now, my friends are biochemistry ...
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846 views

“Estrontium” on poster

I was looking at a poster for an international chemistry olympiad. Its background contains some random elements as periodic table tiles. One of them said "Estrontium." A google search returned ...
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Atomic number ranges in “integral units”?

My textbook says the following: For an electrically neutral or complete atom, the atomic number also equals the number of electrons. This atomic number ranges in integral units from 1 for hydrogen ...
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What, if any, are the differences between radical scavenging and radical quenching?

Hindered amine light stabilizers (HALS), introduced in the 1970s, function mainly as free radical scavengers, although they also may act as quenchers or peroxide decomposers. (Polypropylene: The ...
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Jacobi coordinates - definition

I became quite confused about Jacobi coordinates. Until now I've been used to them as the coordinate system, where coordinates are vectors pointing to the center of mass of previous "subsystem", as we ...
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IUPAC Recommendations for Concentration Units (ppb, ppm)

In a recent interesting post, (Is 1 ppb equal to 1 μg/kg?) it was pointed out that IUPAC advises to abandon parts per million, parts per billion quantities and instead it suggests to employ micromole/ ...
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32 views

What is meant by the term composition in chemistry [closed]

This may seem trivial at first glance, but It is used a lot in introduction to chemistry chapters and so I need to understand what they mean by composition. Yes, I have seen the google definitions, I ...
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39 views

What is the name of “cis/trans” isomerism when all four groups are different?

How would you call a pair of isomers on the picture below? They look a lot like regular cis/trans isomers, except all four groups are different. I can tell they are spacial isomers (stereoisomers) ...
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What are “O-hydrocarbons”? A pharma translator's question (Russian to English, “О-углеводороды”)

A translator colleague is translating from Russian a plan for study of a number of leachable and extractable substances (pharmacology). This Russian text mentions one particular class of chemicals ...
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Standard abbreviations for polycyclic aromatic hydrocarbons, similar to those for nucleic and amino acids?

The Nature paper Characterizing particulate polycyclic aromatic hydrocarbon emissions from diesel vehicles using a portable emissions measurement system addresses polycyclic aromatic hydrocarbons (p-...
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1answer
295 views

Do all polymers contain either carbon or silicon?

Is either carbon or silicon present in every known polymer? If not, is there a small group of elements that, between them, are present in every known polymer, or can polymers be based on a lot of ...
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571 views

Is there a name for this algorithm to calculate the concentration of a mixture of two solutions containing the same solute?

There is an algorithm called "Mischungskreuz" (German for "x of mixing") that is sometimes taught as a shortcut to figure out the following problem: You have two solutions that contain a solute at ...
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How do amphoteric compounds act as acids? [closed]

According to my chemistry textbook, an acid is a compound that gives hydronium ion on dissolving in water but amphoteric compounds like ZnO do not yeild hydronium ion on dissolving in water . I ...
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Is there a difference between equilibrium and steady state?

The term equilibrium is used in the context of reversible reactions that reach a point where concentrations no longer change. The term steady-state is used in enzyme kinetics when the concentration of ...
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I am not able to get the exact definition of a solution [duplicate]

A substance which is in larger proportion by mass is called solvent and which is in lesser proportion is called solute. What if the volume of the substance with lesser mass is more. Will it still ...
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Is there a particular name for a Hill formula or sum formula omitting hydrogen?

Often, single-crystal X-ray diffraction analysis determines the non-H atoms first, and eventually puts hydrogen atoms "as riding" on idealized positions in respect to heavier atoms (e.g., C, O, N), ...
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Meaning of red heat

I have two reactions below. What is the difference between red heat and normal heat? Is it related to iron as a catalyst when it is red hot?
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Apparent contradiction in the name of group 2 elements

From my understanding (I might be very wrong), the "earth" in alkaline earth metals means non-metallic, insolube in water and resistant to heating, therefore the oxides and hydroxides of group 2 ...
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2answers
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What is meant by forward reaction?

While reading my chemistry textbook I came across the phrase: forward reaction is favoured by decrease in temperature in exothermic reactions. I was tripped off by the term 'forward reaction', can ...
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310 views

What exactly is a reducing equivalent and what does it do?

I've encountered this term in the context of cellular metabolism, but I can't seem to find an explanation of what a reducing equivalent is or why it is named this way. Wikipedia was not really helpful,...
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What is chemical decomposition in the context of a crystal or amorphous solid?

The IUPAC Gold Book definition of chemical decomposition is: The breakdown of a single entity (normal molecule, reaction intermediate, etc.) into two or more fragments. That is a very general ...
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What's the difference between “extent of reaction” and “position of equilibrium”?

My chemistry textbook defines the terms in question as follows: Extent of reaction: the relative amounts of products compared with reactants. The extent of reaction is indicated by the value of the ...
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Is the water in an aqueous solution undergoing a reaction considered part of the system or surroundings?

System: In chemistry, a system is a chemical reaction. A system operates within its surroundings. Energy can move between the two. Surroundings: The environment around a particular chemical reaction....
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Sugar: A molecule or crystal [closed]

Is sugar a molecule or a large crystalline structure composed of many molecules? What do we mean when we say sugar?
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10k views

Why do we call O2 oxygen? [closed]

I have been taught that oxygen is a chemical element, in other words a certain type of atom that has 8 protons in its nucleus. So why is O2 called oxygen? It is not a type of atom but rather a ...
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4answers
2k views

Is an isobar the same as an isotope?

I am a little bit confused about what an isobar is. Its online definition is that it's an element with the same number of neutrons but a different number of protons from an element $\ce{X}$. To me, ...
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How do you call the opposite of an ion?

According to IUPAC, an ion is defined as: An atomic or molecular particle having a net electric charge. (source) But how do you call an atomic or molecular particle that does not have a net ...
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Is there a single word antonym for dissociate? [closed]

Teaching ionic and covalent compounds, and one of the differences is that some ionic compounds will dissociate when dissolved but covalent compounds usually do not (salt water vs. sugar water, just ...
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33 views

How to quantify the adsorption affinity of gases?

Is there a term/quantity which shows how 'sticky/adsorptive' a molecule is? I am interested in gas adsorption on steel surfaces in our mass spectrometer and would like to estimate which gases have a ...
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1answer
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Can two atoms with the same amount of electrons but differing electronic configurations be considered isoelectronic?

Can two atoms with the same amount of electrons but differing electronic configurations be considered isoelectronic? For example, would we consider yttrium(I) $(\ce{Y+})$ with configuration: $\ce{[Kr]...
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506 views

What is “mechanistic duality”?

I am doing a general overview of different kinds of dualities present in science. I am quite well versed with the dualities in physics and mathematics. I was searching for dualities in chemistry, ...
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What makes Citrate or Citric Acid an acid?

As far as I know, an acid is something that gives off a proton or hydrogen ion $H^{+}$. But when I look at Citric Acid, There are three $COO^{-}$, which I think is a carboxyl group, that lacks $H^{+...
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Redox and acid-base reactions in planetary atmospheres

I'm a chemistry layperson looking for chemistry expertise regarding atmosphere composition. Earth's atmosphere is oxidizing, but it was somewhat reducing in the distant past before photosynthetic ...
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1answer
323 views

What is 'power law' kinetics?

I've come across a lot of instances where 'power law' description of the kinetics was mentioned, but I cannot think of any integrated rate law that follows something like: $$A(t)=bt^n+c$$ I'm pretty ...
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Understanding Equivalent Wyckoff positions

I'm somewhat confused by the concept of Wyckoff positions in crystal structures. From Quantum Chemistry of Solids by Robert Evarestov, the definition of a Wyckoff position is "all the crystallographic ...
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87 views

Amount concentration versus number concentration

The IUPAC Gold Book defines Amount concentration Amount of a constituent divided by the volume of the mixture. Also called amount-of-substance concentration, substance concentration (in ...
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405 views

What does “intensity of light” mean? [closed]

In this lecture from MIT, the professor defines the intensity of a wave as the square of the amplitude of the wave. But, at the same time, the professor defines the intensity of light as the number of ...
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71 views

Terminology for describing nuclei participating in metallic bonds

I've read many times that in metals (for example sodium metal), what constitutes the crystal lattice is an arrange of atoms, since no electron is given or lost, they are just shared between all the ...
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654 views

Why is Rf called Retardation Factor?

I understand that $$R_\mathrm{f} = \frac{\text{distance traveled by center of analyte spot } (b)}{\text{ distance travelled by solvent front } (a)}$$ What I do not understand is why this is called ...
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Is there a blanket term for all variants (both nuclides and ions) of a chemical element?

I'm hoping to catalogue the various nuclides and oxidation states of an element but can't find a single term that describes them all, save for "chemical element variations". Is there a specific term ...
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What is the difference between “adding a liquid” and “diluting to a liquid”?

Place $\pu{20.0 g}$ $\ce{NaOH(s)}$ in a flask and dilute to $\pu{1.00 L}$ with water. Place $\pu{20.0 g}$ $\ce{NaOH(s)}$ in a flask and add $\pu{1.00 L}$ of water. How exactly do these two ...
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54 views

Photodegradation vs photooxidation

I have been writing a paper about polymers being "aged" by light. Most of this aging happens because light hits atmospheric oxygen and either excites it to its singlet state or causes atmospheric ...
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1answer
440 views

Term for compound of carbon, hydrogen, and oxygen

Is there a term for a compound of carbon, hydrogen, and oxygen? There is hydrocarbon for a compound of carbon and hydrogen. There is also carbohydrate but that requires the ratio of hydrogen to ...
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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?
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What is an alloy called when it melts at the same temperature as something else?

What is an alloy called when it melts at the same temperature as something else? For example, if there is an alloy that melts at the same temperature as glass then it will be susceptible to enameling ...
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Meaning of Molecular Oxygen

Does molecular oxygen just mean the oxygen molecule? Or could it refer to a certain state of the molecule (eg. gas or aqueous)?