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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Scalability of laboratory made Li-S batteries

I was reading this recent research paper: Stabilization of gamma sulfur at room temperature to enable the use of carbonate electrolyte in Li-S batteries and had a question about the scalability of the ...
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Photosynthesis with Algae

Why is the answer to the following question B? What are these other uncontrollable variables?
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3 votes
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What is the standard method for activating molecular sieves with microwave radiation?

Typically, molecular sieves are dried under vacuum at elevated temperatures (about 200 to 300 °C depending on pore size) for several hours. Alternatively, microwave heating has been used for ...
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Well I know ions have same bond order but does it also mean there bond length is same too? [closed]

This is question regarding that if bond order is same then is it necessary to have bond lengths same and if not what is true order of bond lengths
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Preventing solvent evaporation for small scale synthesis

I have been conducting an organic synthesis with quite expensive starting material, so whenever I setup the reaction I only use 0.1 g of starting material. I use 4 mL of toluene to adjust the ...
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Recrystallization of dibenzalacetone [closed]

Why does dibenzalacetone dissolve in hot ethanol?
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4 votes
1 answer
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How do I filter a solution of very fine manganese dioxide?

My synthesis requires potassium permanganate $\ce{KMnO4}$ to oxidize a side alkyl group on benzene ring. The issue is that the brown manganese dioxide $\ce{MnO2}$ is very fine so it is passing through ...
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1 vote
1 answer
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How to achieve desired response of a non Newtonian fluid prepared from silica nanoparticles and polyethylene glycol (PEG 400)?

I am working on non-newtonian fluid project. I have experimented with cornstarch and water and achieved the consistency desired with 55% cornstarch and 45% water. Now I want to create similar outcome ...
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Should sample masses of various samples undergoing Thermogravimetric analysis (TGA) be same?

I want to analyze the thermal degradation phenomena for 3 different samples using TGA. One of these samples comprises Polymer only, while the other two are loaded with two different percentages of ...
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6 votes
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Is there a material that ions can pass through but water can’t?

I was wondering whether there is a material that can pass ions (such as the ions existing in seawater) but not water. I am aware that water molecules are smaller, so they can pass through some ...
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-1 votes
1 answer
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Why is desalination waste usually disposed back into the sea instead of converting it into chemical products?

I was reading about the desalination processes such as reverse osmosis and capacitive deionization and their alternatives. They all work on removing ions from water and disposing them back to sea/...
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-2 votes
1 answer
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Aqua Regia 0.1M solution [closed]

I was reading a method for total digestion, and the method uses 0.1 M aqua regia. I know that aqua regia has 3 parts Hcl and 1 part HNO3, by volume. How would I make a 0.1 M aqua regia solution, is ...
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Evaporation of sample solvent and redissolving

When I conduct a synthesis, after some workups, I usually evaporate large amount of solvent using rotovap, recover compounds sticked to the wall of the flask to the glass vial using small amount of ...
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How much analyte should I use for paper chromatography?

I am looking into using paper chromatography to distinguish between standard drugs and counterfeit drugs for my high school research project. I have decided on using aspirin as the "standard"...
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-1 votes
1 answer
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Chemistry: The Central Science 14th edition, chapter 3, Design an experiment problem

I am new to chemistry as well as StackExchange network, so any advice is appreciated. I tried to answer it myself, but I am sure it is not completely correct and there are certainly alternative ...
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-5 votes
1 answer
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Can I increase the melting point of paraffin wax over 100 degrees celsius [closed]

Can I increase the melting point of paraffin wax over 100 degrees celsius at room temperature and pressure.
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2 answers
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In qualitative analysis for basic radicals, why are group 2 cations not precipitated along with group 4?

To ensure that group 4 cations are not precipitated with group 2, we add dil. $\ce{HCl}$ to ensure only group 2 sulfides of lower $K_\mathrm{sp}$ are precipitated. For group 4, we add $\ce{NH4OH}$ ...
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Buchwald-Hartwig coupling troubleshooting

I am conducting a synthesis using below scheme. And Below is some information about my reaction history. The basic condition is 1 eq of 1-aza-18-crown-6, 1.4 eq of 3-bromothiophene, 1 mol% of ...
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How to synthesize anhydrous zinc(II) nitrate?

I'm interested in making anhydrous zinc nitrate. I know it decomposes fairly rapidly if you heat it. It is also soluble in ethanol. Would another desiccant or a molecular sieve do the trick? Or maybe ...
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How useful is thymol blue (acid) as an indicator?

The pH range of thymol blue (acid) is 1.2-2.8.. This pH range seems pretty useless. Generally, the sudden change in pH for SA-SB titration occurs in the range of 4-10; the sudden change in pH for SA-...
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1 vote
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I need to test fabric for arsenic, and I've found 141-year-old guidance. Is it legit?

I'm a book and paper conservator, and a few years ago had four books to restore. Their endpapers were this gorgeous green silk, but they were badly dry rotted, and needed to be removed. I suspected ...
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1 vote
0 answers
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Does 3-hydroxy-penta-2-one give positive Tollen's test? [duplicate]

I know that alpha hydroxy ketones that can tautomerise to an aldehyde give positive Tollen's test because an aldehyde gives a positive Tollen's test. This molecule however doesn't tautomerise (or ...
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1 answer
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Blue copper acetate solution turning brown

I used white vinegar,hydrogen peroxide and some coins coated in copper and some copper wire. My solution started to have a blue color at the bottom but there were some white particles floating around. ...
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1 vote
0 answers
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Is LCP working well in real experiments? or is it more of an oversimplified principle?

I have a question for people who have applied Le Chatelier's principle (LCP) to their experiment or have knowledge about people who have done that to increase the yield. Essentially, I am curious &...
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-1 votes
2 answers
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What test should be conducted to test for the presence of Aromatic Functional Groups?

To give some background on the different tests I have went over: The Iron (III) Chlorine Test tests for the presence of phenols. However, phenols contain both the alcohol group and the aromatic group ...
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-2 votes
1 answer
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Can Bromophenol Blue Sodium Salt, and Pentane be safely mixed/in contact with each other?

I'm trying to determine if powdered Bromophenol blue is safe to mix with Pentane. I would only need a tiny amount of dye, just enough to tint the pentane. I need to use pentane for it's specific ...
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Liquid water barrier and water vapor permeable membrane sheets

I am running an experiment where I am trying to maintain the relative humidity of a thermally insulated chamber. I am successfully able to hold the humidity using different salt solutions (NACL-75% RH,...
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3 votes
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TLC monitoring of Buchwald-Hartwig coupling reaction using ninhydrin stain

I am conducting a synthesis involving Buchwald-Hartwig coupling reaction. The reagents are 2,3,5-tribromothiophene, 1-aza-18-crown-6, NaOtBu as base, $\ce{Pd_2(dba)_3}$ as palladium source, DavePhos ...
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How to find the standard deviations of lattice parameters after Rietveld refinement with GSASII?

I am trying to learn how to use GSASII. It is different from GSAS/EXPGUI, so I feel hard to find some information from GSASII interface. I want to find what are the values for the standard deviations ...
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3 votes
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Products formed on the reduction of KMnO4 in aqueous solution

The Latimer diagram for $\ce{MnO^-_4}$ is given below: $$ \ce{MnO^{-}_4 ->[0.56V] MnO^{2-}_4 ->[2.26V] MnO_2 ->[0.95V] Mn^{3+} ->[1.51V] Mn^{2+} ->[-1.18V] Mn}$$ Then I have calculated ...
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How to make a thin layer of crystalline barium titanate on copper substrate?

Is it possible to create a thin $\ce{BaTiO3}$ crystal layer on a copper plate by putting the plate in a beaker, pouring in heated hydrofluoric acid that has been saturated with $\ce{BaTiO3}$ powder ...
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1 vote
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Separation of very nonpolar mixtures using column chromatography

I am conducting a synthesis using Buchwald-Hartwig coupling. Below is the TLC result after nearly all consumption of limiting starting material. Th is 2,3,5-tribromothiophene, which is the limiting ...
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Ecell value for non spontaneous reaction

I've done my electroplating experiment but got stuck to calculate my E cell value. So my equations are like these coz I used copper stripes and copper sulphate solution. Some website says E cell can'...
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2 votes
0 answers
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Dissolving NaOtBu in toluene

I am conducting a synthesis using Buchwald-Hartwig coupling, and many reaction conditions use NaOtBu and toluene. Also the internet says that the solubility of NaOtBu in toluene is 130 g/L at 20 ℃. I ...
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2 votes
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Preparation of tertiary Grignard reagents

Has anyone a good and detailed experimental procedure to prepare tertiary Grignard reagents from tertiary alkyl halides on the lab scale (1-5 mmol)? The actual procedures in the literature are very ...
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3 votes
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Experimental Verification of Van der Waals parameters?

I am currently trying to find an academic paper that experimentally verifies the a and b values of Van der Waals forces for carbon dioxide. I can't seem to find this, and am wondering if I am missing ...
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2 votes
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Stability of Mercaptoundecanoic acid and thiol-PEG stored as solids

I am planning to use Mercaptoundecanoic acid (MUA, 98%) and thiol-PEG (O-[2-(3-Mercaptopropionylamino)ethyl]-O′-methylpolyethylene glycol) for functionalisation of gold nanoparticles. The SDS ...
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0 votes
1 answer
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What happens when we react a sulfate salt solution with barium chloride and the formed precipitate with conc. hydrochloric acid?

When I performed this experiment in my school, I could not observe any sort of remarkable change (I must have performed it incorrectly or something). I wanted to know what should have been the correct ...
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How to prepare standard sample of benzene for gas sampling bag?

I need to make a 1 ppm gaseous standard of benzene in nitrogen gas within a Tedlar® gas sampling bag. Is this as simple as injecting 1 μL of neat benzene liquid into 1 L of nitrogen gas within the bag?...
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1 vote
0 answers
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Reaction Workup and Quenching

In the supporting information of synthetic paper by Buchwald's group, They use 2-MeTHF as solvent (See B. General Procedures for Amination part, page 8). After the reaction ends and cools the mixture ...
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What is the product of the following reaction(different sources give different answers) [closed]

$$\ce{FeS +dil HNO3}$$ $$\ce{FeS +conc HNO3}$$ I got different answers to these reactions in different sources Source1 Jd lee: Source 2 Op Tandon: Can anyone please explain which is the correct one ...
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1 vote
0 answers
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How does the temperature of HCl affect the reaction rate of HCl & Mg reaction?

I'm Olivia. I'm experimenting with HCl and Mg. My purpose is to find the change of the reaction rate while I increase the temperature of HCi. According to the study, when I increase the temperature of ...
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3 votes
1 answer
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Interpretation of permanganate-stained TLC spots

When I stain TLC spots with $\ce{KMnO4}$, I found that some spots appear differently as time goes by. Here is the example: The leftmost one is the plate right after staining, and the others are ...
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Using NaCl to change the relative humidity in the humidity chamber [duplicate]

The saturated NaCl will give around 75% RH in various temperature. Is there a way to use different concentration of NaCl in the water to generate different values of RH, i.e., 10% to 90% in the ...
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How are the energies of, e.g. the 4p orbitals of the first transition series, determined?

Take a first row transition metal, say manganese. The 4s and 3d orbitals are occupied in Mn; each orbital's energy can can be definitely determined by ionising that orbital, obtaining the resulting Mn+...
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1 vote
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Mass spectra interpretation for monitoring Buchwald–Hartwig coupling

I am conducting a synthesis involving Buchwald-Hartwig coupling. The starting materials are 2,3,5-tribromothiophene (MW=320.83) and 1-aza-18-crown-6 (MW=263.33). I used $\ce{Pd_2(dba)_3}$ (MW=915.7) ...
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What would happen to the cell potential if two half cells of a galvanic cell were at different temperatures?

I'm doing an experiment where I'm investigating the effect of temperature of the galvanic cell on the cell potential. But during the experiment, I noticed that the two half cells were at different ...
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For Radiochemistry why is a recovery range of 30-110% acceptable for isotopic tracers used for alpha spectrometry analysis of radionuclides?

Just like the title says. I am right now isolating and concentrating several radionuclides from environmental samples using micro-coprecipitation to be able to analyze it on an a alpha spectrometer. ...
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1 vote
1 answer
65 views

In electrolysis, can conductivity be used to predict current?

Since conductivity is the reciprocal of resistivity, it can be used to calculate resistance in the following equation: $$R=\frac{\rho l}{A}$$ $$R=\frac{l}{\kappa A}$$ Could this, along with Ohm's Law ...
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1 vote
1 answer
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Water vapor permeation to the reaction flask

I am conducting a synthesis involving Buchwald-Hartwig coupling. The scale is $\approx10^{-4}$ mols of reagents. After running the reaction at 80 ℃ during 24 hours I found that sealing between the 3-...
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