Questions tagged [notation]

A system of written symbols used to represent qualities or quantities, elements or molecules, or formulas in general. Usually a notation follows a convention or a guideline, often published by IUPAC-IUPAP. This tag should be used for questions regarding the proper use of a notation or misleading or uncommon notation in the scientific literature. Do not confuse this tag with the [nomenclature] or [terminology] tags.

Filter by
Sorted by
Tagged with
0
votes
1answer
3k views

What is the correct net ionic equation for the neutralization of phosphoric acid? [duplicate]

What is the net ionic equation for the reaction between phosphoric acid and sodium hydroxide? I came up with \begin{align} \tag1 \ce{H+ + H2PO4- + OH- &-> PO4^3- + H2O},\\ \tag2 \ce{H+ + OH- &...
5
votes
1answer
2k views

Significant figures used to imply stated error?

The question reads, " express each of the following quantities using significant figures to imply the stated error". a)$2.3 \pm 0.001$ b)$1.989 \pm 0.0003$ I think the first one is 2.300 because ...
2
votes
1answer
125 views

About the way chemicals and molecules are represented

The standard way of representing molecules with letters like $\ce{C}$ for Carbon, $\ce{O}$ for Oxygen etc.; and a lot of lines and double lines like a graph from Graph theory where each letter is a '...
22
votes
1answer
573 views

Structure that breaks InChI

I am currently testing a piece of software that generates the InChI for a given structure. I also want to test error situations as end users will also deliver the mol files that will be used as input ...
1
vote
1answer
134 views

Empirical and Molecular Formulae

I'm not a chemist, and nor do I study chemistry so please try to be gentle. Glucose has the molecular formula $\mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6$ and the empirical formula $\mathrm{C}\mathrm{H}...
2
votes
1answer
243 views

Which ions are accounted for in total and net ionic equations?

There are a number of things I don't understand about ionic equations. First off, when you do net ionic equations, is it correct that you're only focusing on precipitates? The way I understood it, ...
8
votes
2answers
949 views

Should the 'a' in the acid dissociation constant (Ka or pKa) be capitalised?

In science, the negative logarithm of the acid dissociation constant is denoted $\mathrm{p}K_\mathrm{a}$ or $\mathrm{p}K_\mathrm{A}$ depending on the source (lowercase "a" or uppercase "A"). Since it ...
0
votes
1answer
5k views

What does “Anal. Calcd.” stand for written out?

I'm wondering what the abbreviation "Anal. Calcd. stands for exactly. It is put in front of calculated (expected) values for elemental analyses. "Analytically calculated" makes no sense for me, but ...
4
votes
1answer
991 views

What's the convention for the symbols of enthalpies of formation, reaction, etc.?

I frequently encounter two ways of writing enthalpies of some process, e.g. for the enthalpy of formation: $\Delta_{r} G$ (or $\Delta_{R} G$) $\Delta G_{r}$ (or $\Delta G_{R}$) On the IUPAC Gold ...
1
vote
1answer
134 views

What does “/2” in the structure of calcium benzoate mean?

Please see the following figure. This is from the high school chemistry book of my son. He wants to know what does that /2 after $\ce{-COOCa}$ mean. The book is a non English one. And I have changed ...
5
votes
3answers
4k views

How do we represent a molecule in text form?

How do we represent a molecule in text form? A molecule, as a computer scientist I see it as a connected graph of atoms. A connected graph means that beginning at any atom, there is a path to any ...
3
votes
1answer
2k views

Notation “5% solution”

What does 5% aqueous solution of glucose mean? Note that it's just 5% and not 5%w/w. Do we assume it to be w/w? The question is If the osmotic pressure of 5% aqueous soultion of glucose is $\pi_1$ ...
7
votes
2answers
24k views

Why is ethanol written as C2H5OH not C2H6O?

This is balanced equation of fermentation of glucose: $$\ce{C6H12O6(aq) -> 2C2H5OH(aq) + 2CO2(g)}$$ I know that the result of glucose fermentation is ethanol ($\ce{C2H6O}$). What represented in ...
0
votes
1answer
50 views

What does $\mathrm{A}_r(\mathrm{H})$ represent when calculating the average natural weight of an elemental atom?

I have a question that explains the weights and abundances of various hydrogen isotopes, and the question concludes by asking to: Calculate the atomic mass of hydrogen $\mathrm{A}_r(\mathrm{H})$ (...
4
votes
1answer
220 views

Surface Functional Groups/Notation

I'm reasonably unfamiliar with chemical notation, and recently I've come across something I'm not sure how to interpret. In this article, the authors refer to the "surface groups" denoted by $\ce{#Ti-...
1
vote
2answers
3k views

Chemical formula of ethanol and other carbon compounds

Should chemical formula of ethanol be written as $\ce{CH3CH2OH}$ or $\ce{C2H5OH}$? And whats the logic behind it? I have seen the former being used more often, so why is ethane represented by $\ce{...
23
votes
4answers
222k views

How do I type a simple chemical equation in Microsoft Word?

How do I type a simple chemical equation in Microsoft Word? I can do subscripts, but long arrows are more difficult. I can't get them to align with the text. Also, I can't figure out how to put a ...
41
votes
1answer
4k views

Why is methane's molecular formula conventionally “CH₄”, while water is “H₂O” (among others)?

While revisiting some of my old notes about the Miller-Urey experiment, I stumbled across the "equation"... Electricity + $\ce{CH4~/~ NH3~/~H2O~/~CO}$ = Amino Acids This got me thinking. ...
26
votes
2answers
1k views

What does this lambda–sigma notation mean?

I am currently reading the CRC Handbook of Phosphorus-31 Nuclear Magnetic Resonance Data by John C. Tebby (CRC Press, 1991) and on several figures (ex. pages 9 to 14) there is a caption that reads ...

1 2 3 4
5