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21 votes

Is nitroglycerin synthesis within human digestive system from eating soap possible?

According to the metabocard at HMDB — Nitroglycerin, nitroglycerin is only found in individuals that have used or taken this drug. No known metabolic pathways for glycerin lead to nitroglycerin either....
andselisk's user avatar
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13 votes

How to distinguish silver chloride, bromide and iodide?

Nilay Ghosh's method is excellent, but it does not work if the original deposit is a mixture of the three precipitates $\ce{AgCl, AgBr, AgI}$. In this case, it is first necessary to get rid of the ...
Maurice's user avatar
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12 votes
Accepted

What is laboratory air?

Laboratory air is not a designated or special term. All it conveys to the experimentalist is that literally "laboratory" air was used for oxidation. This is perhaps a handwaving way of ...
AChem's user avatar
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12 votes
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Does the side of filter paper matter?

It depends on the reason for the different textures. Some filter papers contain reagents, such as polyaniline-coated filter papers, used for detecting dyes and explosives. In that case, one likely ...
DrMoishe Pippik's user avatar
11 votes
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How to distinguish silver chloride, bromide and iodide?

Aqueous ammonia should do the trick. Silver chloride is soluble in dilute ammonia solution. Silver bromide is sparingly soluble in dilute ammonia solution. Silver iodide is very slightly soluble in ...
Nilay Ghosh's user avatar
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11 votes

Is nitroglycerin synthesis within human digestive system from eating soap possible?

First of all, you don't need to eat soap to get glycerin in your system. Fats are broken down by digestion into glycerin and fatty acids. Glycerin is also available commercially as a cough syrup and ...
Level River St's user avatar
10 votes

Rutherford's gold foil experiment thin sheets

The sheets were thin to maximize the amount of forward scattered signal. As AChem explains, even air would provide a barrier to subatomic particles (thanks @MattBlack for pointing out the glaring ...
Buck Thorn's user avatar
  • 22.5k
9 votes

Rutherford's gold foil experiment thin sheets

The main reason is that Rutherford and Geiger were both interested in exploring the interactions of alpha particles with thin sheets of matter. Mainly, they were rather fascinated by the causes of ...
AChem's user avatar
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9 votes

Question about the differences of white and grey NaH properties

Sodium hydride on mineral oil is grey. When it reacts with water, for example from air humidity it reacts to NaOH which leads to discolouration which is white. One can wash NaH with hexane or THF to ...
raptorlane's user avatar
8 votes

How can I avoid magnesium smoke during melting?

First off, let us assume you are using argon as the inert gas. Nitrogen is not inert to magnesium. You may want to look at the Mg-Ni phase diagram from Ref. 1. The horizontal axis is atomic percent ...
Oscar Lanzi's user avatar
8 votes

What does the blue square on a volumetric flask mean?

The etch mark truly could be blue (or in an other color). But (arguably) it is more common to find such an etch mark in plain white on glass ware, for instance beakers, or flasks, or bottles, or ...
Buttonwood's user avatar
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7 votes
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What does the blue square on a volumetric flask mean?

One of the ASTM International requirements, formerly known as American Society for Testing and Materials, is: ASTM E288 - 10 Standard Specification for Laboratory Glass Volumetric Flasks. 4.5.3 ...
AChem's user avatar
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7 votes
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What role does CaCl2 play in a gelation medium?

Likely, the $\ce{CaCl2}$ induces precipitation, or gelation, in this case. This is called salting out. Another example is using salting out to gel poly(N-isopropylacrylamide) for 3D-printing. Simply ...
DrMoishe Pippik's user avatar
6 votes
Accepted

How can I read an Anschütz/Bennert manometer and how can I make sense of it?

All operations should be gentle: open the valve to the system evacuated if the vacuum applied is good enough, the level of mercury in the right hand (open) leg rises, the level in the left hand (...
Buttonwood's user avatar
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6 votes
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Using potassium dichromate and sulfuric acid to clean test tubes after Tollens’ test

This mixture, often called "chromic acid," is a common way to clean glassware. It is a strongly oxidizing acid which reacts with most organic material, so it is able to remove most types of ...
anon's user avatar
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6 votes

Synthesizing Cyclotetrazane from Hydrazine and Diazene?

What might formally be considered a magnesium salt, $\ce{Mg2[N4]}$, has been formed from the elements at 50 GPa pressure[1]. The salt is recovered as a metastable compound at atmospheric pressure. The ...
Oscar Lanzi's user avatar
5 votes

What meaning does Gibbs energy acquire when applied to solutions?

Gibbs energy (also called free enthalpy) and it's change in context of isothermal and isobaric processes have two major meanings: It is the hard limit for maximum non-expansion work the system (or it ...
Poutnik's user avatar
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5 votes
Accepted

In JJ thomson's cathode ray experiment why is the effect of gravity on the electron not considered?

Various versions of Thomson's original article (Philosophical Magazine, 44, 293-316 (1897)) can be accessed freely online, for instance at Google books, or here (link liable to rot). But you can work ...
Buck Thorn's user avatar
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5 votes

Question about the differences of white and grey NaH properties

Washing in dry pentane was my first thought, too (already visible from the freely available abstract of eEROS). Regarding the determination of the concentration of the active reagent: in the chapter ...
Buttonwood's user avatar
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5 votes
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About whitish layer that formed on chocolate bar

It is solid cocoa butter, that may get "sweated" to the surface and solidified later. It can be caused by long term temperature fluctuations, or just effect if time. So it is mainly the ...
Poutnik's user avatar
  • 42.3k
5 votes
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Percentage Yield

Let: A = $\ce{CaC2}$ B = $\ce{C2H2}$ $$\mathrm{yield}=\frac{m_\mathrm{B}}{m_\mathrm{B}^*}=\frac{m_\mathrm{B}}{n_\mathrm{B}^*\;M_\mathrm{B}}=\frac{m_\mathrm{B}}{n_\mathrm{A}\;M_\mathrm{B}}=\frac{m_\...
Sam202's user avatar
  • 1,654
4 votes

What kind of adhesive could I use as a binding agent for calcium chloride?

Sorry, but this is unlikely to work if exposed to ambient air, except perhaps atop an arid mountain. $\ce{CaCl2}$ is sufficiently hygroscopic that it dissolves in the water absorbed, i.e., deliquesces....
DrMoishe Pippik's user avatar
4 votes
Accepted

pKa and pKb in solvents other than water

Bruckenstein and Kolthoff give some values in the abstract, which is available in the free preview. Notable among acids: perchloric acid, $pK_a=4.87$; hydrogen chloride, $pK_a=8.55$. Also given is an ...
Oscar Lanzi's user avatar
4 votes

Can pure hydronium exist?

$\ce{H3O+}$ is a ion – a charged particle. As an isolated ion, "naked" in vacuum or gas, or hydrated in water, it is a common thing. But with macroscopic quantities, it is more complicated. ...
Poutnik's user avatar
  • 42.3k
4 votes

What could be used to thicken Ferric Chloride solution?

Not an answer, but suggestions for you to test the thickeners (and surfactants) added to: Phosphoric acid-based Naval Jelly® Rust Dissolver (thixotropic polysaccharide, silicon dioxide) and This HCl-...
DrMoishe Pippik's user avatar
3 votes

Would having a greater H-bond donor count make a substance more readily enter a twig?

All else being constant, more H bond donors/acceptors will correlate with lower hydrophobicity. Greater hydrophobicity is expected to lower aqueous solubility. This is a well known principle within ...
Buck Thorn's user avatar
  • 22.5k
3 votes

Term for one chromatography sample affecting the next?

Yes, it is termed "carryover". Carryover is recognized as the presence of a small analyte peak that appears when a blank is injected following the injection of a sample that produces a ...
Galen's user avatar
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3 votes
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Reduction of La(NO3)3 to La(NO2)3

Zinc powder can reduce nitrate to nitrite, see Morita and Nakamura[1]. Lanthanum is much higher than zinc in the EMF series, so a side reaction of reducing the lanthanum ions will not occur. However, ...
Oscar Lanzi's user avatar
3 votes

betamechaptoethanol smell

Some sulfur organic compounds have rather a strong odor. For your delectation, may I suggest reading Derek Lowe on the not dissimilar compound, thioacetone. For further documentation, see Grayson Van ...
DrMoishe Pippik's user avatar
3 votes

Can pure hydronium exist?

Absolutely, and it's not even difficult. Sure, in the dilute gas phase naked $\ce{H3O+}$ is commonly found simply due to the relative ease of formation and abundance of $\ce{H+}$ and $\ce{H2O}$, in ...
Nicolau Saker Neto's user avatar

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