Questions tagged [experimental-chemistry]

This tag should be applied to questions relating to the theory, design, techniques or performance of chemical experiments. This includes but is not limited to theoretical structures, expected products, thermal calculations, and empirical analysis. Additional tags should be applied to narrow down the field of research.

243 questions with no upvoted or accepted answers
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12
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225 views

Why is Diiron nonacarbonyl so exceptional?

My textbooks says: With exception of $\ce{Fe2(CO)9}$, all other metal carbonyls are soluble in hydrocarbon solvents. Weller, M.; Overton, T.; Rourke, J.; Armstrong, F. Inorganic Chemistry, 6th ed. ...
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81 views

Is there a structured data source containing information on the World Health Organisation's Stability Testing Policies?

Hoping to automate some product testing guidance software, I've been attempting to find a (hopefully live, up-to-date) Database, Web-service, or other structured data source containing the ...
10
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1answer
2k views

Calculation of Atomic weight percentage in AAS

I am currently doing doping studies in a system similar to this ($\ce{A_{x}B_{1-x}}$) and I have to find atomic weight percentage of $\ce{B}$ element using atomic absorption spectroscopy(AAS). I have ...
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97 views

Triplet oxygen ene reaction with enols

It is observed that whereas singlet oxygen is required for an ene reaction with an alkene to give an allyic hydroperoxide, triplet oxygen will react similarly with an enol to give an alpha-hydroperoxy ...
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715 views

Can I make Ferrofluid without evaporating Ammonium?

I want to make ferrofluid, which is ferromagnetic particles suspended in a carrier fluid. Three methods I have seen involve using magnetic ink (for MICR codes), cassette tapes, or ferric chloride as ...
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175 views

How to get defect-energy level diagram from PL data

I am reading this article Phys. Chem. Chem. Phys. , 2011, 13, 14902-14905 and seen that the authors have drawn a image of defect level using PL data Can you explain me how this diagram can be drawn ...
8
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48 views

Quantitative Transfer of Volatile Standards

(Edited w/ updates) Okay, long story short I work in a lab which has been working on cannabinoid analysis (in the licensed Canadian market) and have had a lot of issues surrounding the standards/...
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307 views

How are polarizabilities measured experimentally?

Most common spectroscopies that produce either a full spectrum, a tensor, or a scalar value have a specific instrument associated with them that is relatively self-contained and not custom. For ...
8
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1answer
2k views

Role of methanol in NaBH4 reduction

In reduction of carbonyls (aldehyde and ketones) to alcohols using NaBH4/Methanol, alkoxides are formed with the Boron which usually gets protonated on addition of water/acid. My question is what is ...
8
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1answer
98 views

Will the sulfur-iodine cycle and Haber Method work at lower pressures and temperatures?

I have a year-long research project next year in my senior year of high school, in which we have to make some product or prototype to solve some issue. My interest was in the Liquid Fluoride ...
7
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51 views

Linear PEI Solution Making

I'm making a solution with linear poly(ethyleneimine) $\ce{[CH2CH2NH]_{n}}$. The bottle indicates that the substance is hygroscopic and must be dealt with under inert gas. Is this really necessary? ...
7
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1answer
449 views

Does phosphoric acid remove stainless steel electropolished layer?

Electropolished stainless steel has a high corrosion resistance due to the oxide film that is created during electropolishing. The film mainly consist of chromium(III) oxide. Phosphoric acid is ...
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217 views

Role of pH in azo C-coupling reaction, continued

In the question, "What is the role of pH in azo coupling reaction of diazonium with phenol and aniline?" asked by @DhrubaBanerjee and answered by @Klaus-DieterWarzecha, I find several ends untied. I ...
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420 views

What is the fabric in heating mantles made of?

An ordinary lab heating mantle often has a white fabric coating for the flask compartment, which looks like an inorganic fiber: Image source I'm pretty sure that for some time in the past ...
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759 views

Finding theoretical mechanism of sodium thiosulphate and hydrochloric acid

In class we conducted an experiment where we timed reactions between sodium thiosulphate and hydrochloric acid. We kept the concentration of the $\ce{HCl}$ constant, while changing the concentrations ...
6
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1answer
322 views

How would you measure the rate of this SN1 reaction?

I am performing the following $\mathrm{S_N1}$ reaction: $$\ce{t-BuOH + HCl -> t-BuCl + H2O}$$ I would also like to measure the rate of this reaction, but I cannot seem to find a way. I initially ...
6
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660 views

Mixing naphthalene, formaldehyde and sulfuric acid (Marquis reagent + naphthalene)

Excuse me if this a dumb question but it has haunted me for years. Back in my old school days I mixed naphthalene, formaldehyde and sulfuric acid in a mad attempt to make $\mbox{2-Methoxynaphthalene}$...
6
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894 views

Tables/database/literature of specific or optical rotation

I'm looking for a comprehensive reference of experimental specific rotation or optical rotation data. It can be a published literature review, a free web database with API access or one that permits ...
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254 views

Reduction of vanadyl ion

I want to reduce vanadyl to vanadium (III), can somebody please suggest some appropriate methods for it? I am trying to make a redox flow battery for a project but I have only vanadyl sulfate.
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63 views

An unknown glassware piece from our cupboard

We have multiple of these. It is a small glass funnel with splits into 3 spouts from it. Now, we are thinking it might be similar to a cow receiver, however, I have never seen one this small or ...
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32 views

Unknown possibly handmade glassware- description in information below

Okay, Another random item from the cupboard (unknown users or discipline of life sciences unknown) could be anything up to 40 years old.... This appears to be a 2 neck quickfit adapter (B19 and B14) ...
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106 views

What is a good solvent for pentacene?

I am doing an experiment with pentacene molecule ($\ce{C22H14}$). I want to clean my sample reservoir after using it. But I show in some literature that it is slightly soluble in organic solvent. ...
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111 views

Waterproofing and recycling paper

I've recently begun studying about waterproofing paper. Through what I learned is that the reason why paper absorbs water so easily is mainly because of it's material composition. Paper is generally ...
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65 views

Should I add more of a trihydrate chemical to a solution if recipe calls for hemihydrate?

I am running phosphate by the ascorbic acid method (SM 4500-PE, PDF), and making the antimony potassium tartrate reagent. Standard methods uses $\pu{1.3715 g}$ of $\ce{K(SbO)C4H4O6 * 1/2 H2O}$ per $\...
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457 views

Why does the open circuit voltage of a battery decrease with increase in pH of electrolyte, but the voltage across a load increase?

I tested a cell which had aluminum sulfate as its anode electrolyte (12 grams aluminum in 50 mL water and a pH of 3.2), and potassium hydroxide as the cathode electrolyte (5 grams of KOH in 200 g of ...
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113 views

Expedient phosponium synthesis (for Wittig)

I have been making ethyltriphenylphosphonium bromide (somewhat of a time crunch, would have used iodoethane instead of bromoethane if we didn't have to wait for it). All the syntheses I see of Wittig ...
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777 views

Why are NBr3 and NI3 unstable, but NF3 is stable?

Why are NBr3 and NI3 unstable, but NF3 is stable? Is there any reasoning behind the stability? I found that one nitrogen can accommodate fluorine easily, but not the others. Also, I don't understand ...
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553 views

Oxidation of dihydropyridine

This is a step in a experiment I have carried out. Usually DDQ (dichlorodicyanoquinone) would be used here to oxidise the dihydropyridine. However in this case Nitric Acid is being used as the ...
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97 views

Why do people consider caffeine ineffective after its half-life?

Assuming you take $\pu{200mg}$ of caffeine, it's half life is roughly 6 hours. So after 6 hours there should still be $\pu{100mg}$ of caffeine in your body. Then why is it generally said that after ...
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540 views

Experimentally proving the mechanism and rate laws of SN1 & SN2 reactions

I have been given the task of experimentally proving the rate laws and mechanisms of $\mathrm{S_N1}$ and $\mathrm{S_N2}$ reactions. Unfortunately, the only equipment I can use is limited to analytical ...
4
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618 views

An alternate purification process for sugar separation form bee honey?

Bee honey contains 75% sugars (Fructose, Glucose, Maltose, Sucrose and others), some water and low amount of different compounds (up to 5%) Wiki. Basic purification is done by addition of phosphoric ...
4
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271 views

What causes the yellowing of the linear alkylbenzene (LAB) cocktail?

In our lab, we use the liquid linear alkylbenzene (LAB) cocktail mixed with 2g/L 2,5 diphe-nyloxazole (PPO) as the organic scintillator for radiation detection. The new LAB cocktails are stored in the ...
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99 views

Synthesizing monodisperse PbS quantum dots

For a research project, I am trying to synthesize lead (II) sulfide quantum dots using the method of Li et al.. I am injecting sulfur dissolved in 1-octadecene into a mixture of $\ce{PbO}$, oleic ...
3
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1answer
63 views

Is it more precise to measure a substance as a solid or as a liquid?

If I have a substance and want to obtain an exact quantity of it, is it better to measure it as a solid or as a liquid? In other words, if I have, for example, NaCl crystals I can weigh the crystals ...
3
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1answer
75 views

Experimental measurment of thiosulphuric acid decomposition kinetics

Problem I am trying to do a kinetics analysis on the following reaction: $$\ce{Na2S2O3 {(aq)} + 2 HCl {(aq)} -> S {(s)} + 2 NaCl {(aq)} + SO2 {(g)} + H2O {(l)}}$$ Suggested Method However, most ...
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42 views

Why is this scintillator component turning into a milky-white emulsion?

I am a chemistry and physics double major doing some chemistry work in a nuclear physics lab. My mentor is a physicist, so his area of expertise is occasionally mismatched with what I need for my ...
3
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143 views

Is this a viable method for graphene production?

In a cup of warm water add sugar until it no longer dissolves then add a few spoonfuls more of sugar. Drop in a small amount of graphite powder into the sugar water mixture. Stir it up well. There ...
3
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0answers
524 views

Why is the silver nitrate chemical test more favorable than that of sodium iodide?

Two tests to determine the presence of alkyl chlorides are the silver nitrate in 1% ethanol and sodium iodide in 15% acetone tests. These two tests both produce a precipitate when added to chloride ...
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70 views

How can I test fruits and vegetables for certain insecticides?

I live in Turkey and I don't feel safe eating the fruits and vegetables that I enjoy that are plentiful here. After reading this article, I have been washing all fruits and vegetables with water and ...
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0answers
75 views

Separation of Regioselectively Alkylated Ionic Solid

How would one go about separating a solid mixture of regioselectively alkylated solids. I'll give a specific example. Take the hypothetical alkylation of methylpentazole with MeI. There are three (...
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0answers
104 views

Chemistry Behind TMOS Aerogel

I have found out how to make silica aerogel. Currently, the solution that I need to create to make the gel requires tetramethyl orthosilicate or TMOS. Furthermore, the procedure requires me to make ...
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0answers
161 views

How does the rate determining step determine the overall speed of the reaction if it is the first step in the reaction?

I can imagine it determining the rate of the whole reaction if it is the last step since that means that we will have lots of the reactants needed for the rate determining step, synthesized in earlier ...
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0answers
63 views

What is the mechanism of hydroperoxide reduction by bisulfite?

I am using bisulfite to quench allylic hydroperoxide products from a singlet oxygen ene reaction, to the corresponding alcohols. What is known about the mechanism of this reaction, and in particular ...
3
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0answers
384 views

What substances in ash may create a green colour and are also soluble in water?

I have an ash that is high in $\ce{K2O}$ ($ \gt 30 \text{%}$), $\ce{SiO2}$ ($ \gt 10 \text{%}$) and $\ce{CaO}$ ($ \gt 10 \text{%}$), with $\ce{P2O5}$ ($5 \text{%}$) and $\ce{MgO}$ ($3 \text{%}$) also ...
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29 views

Most nucleophilic oxygen base

What is the most nucleophilic known monoanionic oxygen base? I am thinking hydroperoxide ion or perhaps an alkylperoxy anion. But perhaps there is something I am missing.
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457 views

Why is my Cu2O Cuprous Oxide Not Red

A thin film sample of polycrystalline Copper(I) Oxide (Cuprous Oxide, $\ce{Cu2O}$) on quartz looks reddish in the center but bluish/grayish at the sides where the film is thicker. The same thin film ...
3
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0answers
396 views

What does the number mean in Sylgard 170, Sylgard 184, etc?

My lab uses a lot of PDMS, a silicon-based organic polymer, to make microfluidic devices. PDMS is available in many different formulations, and we usually use Dow Corning's Sylgard 184. Recently we ...
3
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0answers
376 views

Selectivity of Zinin Reduction

What is it, that makes the Zinin Reduction a selective reduction, and not a complete reduction, in the case of dinitrobenzenes? Also, is the reaction a selective one even when it is done for aliphatic ...
3
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0answers
1k views

Lassaigne's test for sulfur

The sodium fusion extract is acidified with acetic acid and lead acetate is added to it. A black precipitate of lead sulphide indicates the presence of sulphur. What is the need for acidification of ...
3
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0answers
1k views

Should I round an experimentally determined reaction order to an integer?

For a lab experiment I did, I'm calculating the reaction order for one of the reactants using data from two trials, both rates and the concentration of that reactant during each. $$ \frac{\text{Rate}...