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A thiol is a chemical compound of the form , with an organic group attached to sulfur. The conjugate base is ; cysteine and mercaptoethanol supply examples of thiol groups. Two thiol groups can undergo oxidation to form a disulfide bond. [ref]
Choline is a positively charged organic ion containing a trimethylammonium group and a two-carbon chain ending in a hydroxyl group. Its permanent positive charge distinguishes it from an amine that is neutral until protonated.
Choline is part of phosphatidylcholine and a precursor of acetylcholine. These roles connect one small molecular headgroup with both cell membrane structure and chemical communication.
Methanol is the one-carbon alcohol . Its hydroxyl group can donate and accept hydrogen bonds, making its behavior different from that of the similarly small methane molecule.
It mixes readily with water and participates in reactions characteristic of alcohols, including formation of methyl esters. The methyl group and hydroxyl group together determine its polarity and chemical reactivity; an alcohol is not simply a hydrocarbon dissolved in water.
The carboxylic acid-derived ester linkages in a triglyceride or typical glycerophospholipid have the form . Here the acyl group is attached through oxygen to the glycerol-derived part. See IUPAC Blue Book, P-65.6: esters.
A hydrocarbon contains only carbon and hydrogen. A fatty acid also contains oxygen; calling its long chain a hydrocarbon region does not make the whole fatty acid a hydrocarbon. See IUPAC Gold Book: hydrocarbons.
Glycerol has three carbon chemical atoms and three groups. It supplies the scaffold of triglycerides and glycerophospholipids, but is not itself a long hydrocarbon chain. See Biology 2e: glycerol.
Sodium chloride contains sodium cations and chlorine anions in a ratio; its formula unit has zero net electric charge.
Phenol is benzene with one ring hydrogen replaced by a hydroxy group. That O–H group supplies the hydrogen bond donor in the experiment under hydrogen bond acceptor. [ref]
https://openstax.org/books/organic-chemistry/pages/17-1-naming-alcohols-and-phenols. McMurry: phenol naming and structures
Benzene has a planar ring of six carbon chemical atoms, each bearing one hydrogen. Its electron density is distributed over the ring; the alternating covalent bonds in one resonance structure do not describe alternating actual bond lengths. [ref]
The chemical compound used in the conductometric determination of activation energy. Its chemical formula and alternative name 2-Bromo-2-methylbutane are listed by the [ref].
Sodium hydroxide is the ionic compound . Dissolution in water supplies sodium and hydroxide ions, giving a strongly basic solution.
It illustrates the distinction between formal salt concentration and the equilibrium activities used in accurate pH calculations. Neutralization consumes hydroxide, while the sodium ion can remain a spectator in the net acid-base equation.
Tetradecyltrimethylammonium bromide is a cationic surfactant with a fourteen-carbon hydrophobic chain and a positively charged trimethylammonium headgroup; bromide supplies the counterion.
In water, aggregation into micelles depends on concentration and solution conditions. Comparing related surfactants with different chain lengths helps separate the influence of hydrophobic chain size from that of the charged headgroup.[ref]
https://www.ebi.ac.uk/chebi/CHEBI:3565. ChEBI: cetrimide, chemical identity and structure
Fluorescein is an organic dye whose electronic structure supports strong visible fluorescence under suitable conditions. Its protonation state affects both absorption and emission, making pH part of the measurement conditions.
Attaching a fluorescein-derived label to a biological molecule can make its location observable by fluorescence microscopy. The label is a reporter: interpreting the image requires distinguishing label brightness from the amount of the target molecule.
Manganese dioxide is the oxide conventionally written . Assigning each oxygen oxidation state −2 gives manganese formal oxidation state +4.
Different crystal forms and defect populations can change its electrochemical and catalytic behaviour. An oxidation-state calculation establishes formal electron bookkeeping, rather than uniquely specifying the material's structure or reaction rate.
[ref]
Chemistry 2e by Paul Flowers and others. Chemical equations, oxidation-state conventions and solution equilibria; chapters4,14–17
Sulfuric acid is , with two acidic protons and successive hydrogen-sulfate and sulfate conjugate-base forms. The two dissociation steps need not have the same equilibrium behaviour.
In a permanganate-iron titration, sulfuric acid supplies the acidic medium needed for the intended redox stoichiometry. Choosing an acid involves its counterion as well as its proton contribution, because other ions can participate in competing reactions.
[ref]
Chemistry 2e by Paul Flowers and others. Chapter14, Acid-Base Equilibria: sulfuric acid and successive dissociation
An ionic compound of sodium cations and hydrogen anions. Its oxidation state assignments are for sodium and for hydrogen.
Pinned article: Introduction to the OurBigBook Project
Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
Intro to OurBigBook
. Source. We have two killer features:
- topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculusArticles of different users are sorted by upvote within each article page. This feature is a bit like:
- a Wikipedia where each user can have their own version of each article
- a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
Figure 1. Screenshot of the "Derivative" topic page. View it live at: ourbigbook.com/go/topic/derivativeVideo 2. OurBigBook Web topics demo. Source. - local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
- to OurBigBook.com to get awesome multi-user features like topics and likes
- as HTML files to a static website, which you can host yourself for free on many external providers like GitHub Pages, and remain in full control
Figure 2. You can publish local OurBigBook lightweight markup files to either OurBigBook.com or as a static website.
Figure 3. Visual Studio Code extension installation.
Figure 5. . You can also edit articles on the Web editor without installing anything locally. Video 3. Edit locally and publish demo. Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension. 
- Infinitely deep tables of contents:
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact