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.

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11
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0answers
85 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
3k 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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806 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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185 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 ...
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161 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/...
8
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1answer
102 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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856 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 ...
7
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1answer
689 views

The open circuit voltage of a battery: Does it decrease with increase in pH of electrolyte while the voltage across a load increase?

Why does the open circuit voltage of a battery decrease with increase in $\mathrm{pH}$ of electrolyte, but the voltage across a load increase? I tested a cell which had aluminum sulfate as its anode ...
7
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1answer
549 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 ...
7
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1k 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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492 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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55 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? ...
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868 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 ...
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1k 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 ...
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133 views

Distilling milligram quantities of oil like it's late 1970s

In a currently retracted* manuscript by Tomas Hudlicky [1, Retraction Watch] the following has been noted: Fifty years ago professors took an active part in all laboratory instructions and they ...
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74 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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1k 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 ...
5
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280 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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45 views

Why is the Suzuki coupling done under inert atmosphere?

There are plenty of sources saying that the Suzuki coupling is air-sensitive (even though there are some versions that require oxygen). However I'd like to know why a typical Suzuki coupling is air-...
4
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76 views

Why does my drierite turn bright bright blue, instead of pink?

Drierite a brand name of a commonly-used, calcium sulfate-based dessicant in many chemistry labs. The lab I work in has a dessicator box we use to store hygroscopic materials. It isn't a a true dry ...
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95 views

Why is the experimental pH of vinegar (acetic acid) so much higher than expected?

I bought some sodium hydroxide on Amazon and went about titrating solutions I make with it. As I'm an amateur chemist at home, I have limited tools. A pad of paper, some 5% acetic acid vinegar, and ...
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40 views

membrane for a reverse osmosis desalination experiment

We are second year cram schoolers , we are currently working on a project tackling water desalination by reverse osmosis and are required to do an experience. During the process, we encountered some ...
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38 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) ...
4
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1answer
382 views

Extrapolating from a calorimetry lab to find a new delta T with different volumes and grams of substance

So, we just finished an AP chem lab where the question was basically: Given the results of the lab were that $\pu{5 grams}$ of $\ce{CaCl2}$ and $\pu{45ml}$ of water produced a $\pu{13.33 ^\circ C}$ ...
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195 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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222 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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98 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
73 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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159 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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590 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 ...
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714 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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650 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 ...
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1k 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 ...
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343 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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103 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 ...
4
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1answer
65 views

Does pH gets affected by pressure?

My attempt- I thought that pH is h+ ion concentration and change in volume will change its equilibrium according to le chatelier's principle . But I want to know is it correct or it needs some ...
3
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0answers
34 views

Why neglecting Bradford Solution Volume in the assay?

I would like to know why do we not need to take account of Bradford agent solution in dilution calculation? For example, $\pu{2.5 \mu g mL-1}$ BSA will calculate from $\pu{0.4 \mu L}$ of $\pu{1 mg mL-...
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0answers
41 views

Can color-changing leuco dyes be used to indicate when a certain molecule binds to another in a textile fabric?

Thermochromic leuco dyes change color when the temperature changes. I want to use leuco dyes to make a color-changing fabric. However, instead of using temperature to induce color changes, I want the ...
3
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0answers
22 views

Extract seaweed iodine from petroleum ether and cyclohexane

I'm working on iodine extraction from seaweed by using petroleum ether and cyclohexane. I have already observe the presence of iodine in the solution but I don't know how to extract the iodine in a ...
3
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0answers
15 views

Safety concerns (Cyanide): Dicyandiamide + Polyamine condensation reaction

I am attempting to synthesize a poly-amine polymer by condensation between dicyandiamide (also known as cyanoguanidine and dicyandiamine) and diethyltriamine. The polymer is a kind of dye fixative ...
3
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0answers
83 views

Which acetate salt is blue and turns yellow when dissolved in water?

***Update Some questions I am considering to try to answer this question; When dissolving the powder in acetic acid, which ions are present? From what I've read, I haven't found any acetate salts ...
3
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1answer
94 views

Removing Iron Oxide from a Floppy Disk?

Don't ask me why, but I did an experiment where I tried to remove the magnetic iron oxide layer from a floppy disk by soaking it in HCl for a week. I put pieces of floppy disk in 0 - 1 M HCl, then ...
3
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0answers
59 views

Molar ratios not leading to complete reaction in Schweizer's reagent production

In my home lab, I've reacted $\ce{Cu(OH)2}$ with aqueous ammonia to produce Schweizer's reagent. However, I'm surprised by the amount of ammonia required to react with this amount of $\ce{Cu(OH)2}$. ...
3
votes
1answer
176 views

Pipette pumps durability

According to your experience, in terms of durability and longevity of the tools, which one of these types of pipette pumps is better and why? Tri-valve pipette bulb Syringe pipette pump Electronic ...
3
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0answers
54 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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0answers
180 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
815 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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0answers
77 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 (...
3
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0answers
123 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 ...
3
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0answers
177 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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