Spoiler warning: Be aware that this page contains a lot of MathJax, so it will probably need quite a while to load completely.

Sandbox II has become as clogged as Sandbox I was (and is), especially for users with 10,000 reputation or above. So, here is a new new post...

Before you delete a post here, please reduce it to one line without MathJax.

Old formatting sandboxes:

  • $\begingroup$ Why do we have to reduce it to one line without MathJax? $\endgroup$
    – Micelle
    Jun 19 '20 at 14:53
  • 7
    $\begingroup$ @Micelle deleted posts are viewable by users with >10,000 reputation, so it's just a courtesy thing. Long mathjax posts make the page load slowly. $\endgroup$
    – orthocresol Mod
    Jun 19 '20 at 14:55

Anything I post here in Sandbox III is strictly temporary and will be deleted in a few days, maximum.

The Dielectric interface block from my LightStone free optical calculus software that adds on to ExtendSim CP 10.0.8 (a commercial simulation program, from Imagine That, Inc., for Windows-based PCs). I have no financial relationship with Imagine That, Inc. I am simply a user of their simulation software since 1989.

Dielectric interface block

Jones to Mueller converter

Matrices from Jensen et al.


Common misspellings

This table is indexed alphabetically in the first column. Please feel free to add to it.

The second column contains a link to the appropriate Wikipedia page.

Wrong Correct Remarks
Breddts Bredt’s [rule] Julius Bredt.
carbonation carbocation Carbonation is what you do to make fizzy drinks.
Clemenson Clemmensen [reduction] Erik Christian Clemmensen.
die dye “Die” is only for “die Farbstoffe”.
Diel's Adler Diels–Alder [reaction] Otto Paul Hermann Diels; Kurt Alder.
fajan's Fajans’ [rules] Kazimierz Fajans
flourine fluorine
Friedel–Craft's Friedel–Crafts The guy's name was James Crafts, not James Craft.
gasses gases One outgasses gases.
Gibb's Gibbs [energy] Josiah Willard Gibbs.
Henderson–Hasselbach Henderson–Hasselbalch [equation] Lawrence Joseph Henderson; Karl Albert Hasselbalch.
iconic ionic [bond]
morality molarity The moral of this story is that only people can be moral or amoral.
Nerst Nernst [equation] Walther Hermann Nernst.
phosphorous phosphorus This refers to the element. See also next entry.
phosphorus acid phosphorous acid This refers to the acid $\ce{H3PO3}$. See also previous entry.
pie pi/π [bond] Pie bonding is for SeasonedAdvice.SE.
seperation separation [process] “Seperate” is not even an English word.
stigma sigma/σ [bond] Stigma bonding is for Christianity.SE or MedicalSciences.SE.
Tollen's Tollens’ [reagent] Bernhard Tollens.
Vander-Wal's, Van der walls van der Waals [force] Johannes Diderik van der Waals. Note it's lowercase “v”.
Vant-hoff van 't Hoff [equation] Jacobus Henricus van 't Hoff.

Somebody complained that the reaction I asked about doesn't exist. Why is this a problem?

Chemistry is an experimental science first and foremost, and this is especially true of synthetic chemistry, whether organic or inorganic.

What this means is that: we don't come up with theories from first principles, then use them to predict reactions. [We're getting better at doing this using quantum mechanics, but it's still very early days.] Instead, we find out that a reaction happens, and then we work backwards to come up with a model that explains it.

The ultimate source of "truth" in chemistry is not defined by our theories, but rather by our experimental observations. The theories only exist because they can explain experimental evidence.

[Incidentally, that's why there are so many exceptions to the theories. Many of them have a limited range of validity, in that they can only explain a certain subset of the experimental observations we have. A simple example is the octet rule. It works for quite a lot of organic molecules, but can completely fall apart in other contexts.]

So, asking "why does this reaction occur?" is only sensible if that reaction has actually occurred!

If nobody has done it before in real life, then we have no way of knowing whether it would actually occur. And secondly, if it doesn't actually occur and we come up with a theory to explain it, then there is no guarantee that that theory would be correct.


$h=\frac{I_{\text{const}}\cdot R_{\text{ref}}(1+\alpha\Delta T)}{A_{\text{filament}}(T-T_{\text{flow}})}$


$\require{begingroup}\begingroup$ $\def\pi{\neq 3.14}$

$\require{begingroup}\begingroup$ $\def\pi{\neq 3.14}$

The ratio of a circle's circumference to its diameter is $\pi$.

The ratio of a circle's circumference to its diameter is $\pi$.



  • 1
    $\begingroup$ $\pi here doesn't leak through: $\pi$ $\endgroup$
    – orthocresol Mod
    Jan 30 at 15:15

enter image description here


The following are the definitions of 'mole' represented in the form of equations:

(1) Number of moles of molecules $=\frac{\text { weight in } g}{\text { molecular weight }}$

(2) Number of moles of atoms $=\frac{\text { weight in } \mathrm{g}}{\text { atomic weight }}$

(3) Number of moles of gases $=\frac{\text { volume at NTP }}{\text { standard molar volume }}$ (Standard molar volume is the volume occupied by 1 mole of any gas at NTP, which is equal to $22.4$ litres.)

(4) Number of moles of atoms / molecules / ions / electrons $=\frac{\text { no. of atoms } / \text { molecules } / \text { ions } / \text { electrons }}{\text { Avogadro constant }}$

(5) Number of moles of solute $=$ molarity $\times$ volume of solution in litres or no. of millimoles = molarity $\times$ volume in $\mathrm{mL}$.

$\frac{\text { Millimoles }}{1000}=$ moles

(6) For a compound $\mathrm{M}_{\mathrm{x}} \mathrm{N}_{\mathrm{y}}, x$ moles of $\mathrm{N}=y$ moles of $\mathrm{M}$


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