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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What is the density of solid methane at atmospheric pressure?
I'm curious about the density of solid methane since it might be slightly more energy dense than liquid natural gas. The materials project computes the density to be 0.433 g/cm3 which is higher than ...
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Why is the Molar mass of CO2 different than the weight of the sum of its particles?
The Molar mass of CO2 is stated to be 44.009 grams per mol
But in a calculation of the weight of each atom's particles((Electrons,Protons,Neutrons) times Avogadro's constant
I get 44.36 grams per mol
...
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Is it safe to use borosilicate lab glass as an autoclave?
I'm attempting to do a one-pot synthesis that requires autoclaving the chemical mixture. I thought this process would be greatly simplified by using the lab glass itself as the autoclave in situ ...
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NMR pulse sequence for precise measurements of coupling constants?
The usual procedure for measuring $J$ coupling constants in NMR is to record a 1D spectrum and estimate the constant from the differences of peak frequencies. Fitting the spectrum to a lineshape ...
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Cooling a 100°C beaker in cold water
In my nanoparticle synthesis, I need to cool a beaker with boiling solution (50mL beaker) rapidly to arrest a reaction at a specific size of nanoparticle. Letting the hot beaker cool passively is too ...
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How to avoid side reactions when making boronic esters (Homocoupling, Hydrogen specie)?
I have been working with suzuki couplings using substituted naphtalenes (typically 2-bromo-7-R-naphtalene) for a while now, and making the boronic specie is always a pain.
I can't make the boronic ...
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Will a nitro aryl resist an halogen exchange using nBuLi?
I would like to boronate 2-bromo-6-nitro-naphtalene using nBuLi and quenching with 2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane. Since there is no alpha proton to the nitro, and that the nitro ...
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After adding the electrophile (BOMe3) in an halogen exchange (nBuLi) reaction, why do we leave the reaction stir overnight?
Very basic question.
In all the procedures for halogen exchange reactions reported using boronic compounds, the reaction is left to run ON at room temperature after addition of the boronic specie.
In ...
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How to quantify the concentration of sodium nitrate leftover from eutrophication through titration?
In my experiment, I am trying to quantify the nitrate absorption by duckweed. I need a titration method to measure the left over nitrate levels in the solution. However, this is to be done in a school ...
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Brilliant fluorescent properties of Na2S(x) obtained from Na2SO3 or Na2S2O3
When $\ce{K2SO3}$ or $\ce{Na2SO3}$ is heated strongly by any method (in a flame, in an electric arc, on a metal plate in an induction heater), the resulting residue should be a mixture of $\ce{Na2SO4/...
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Fundamental reasons for using vapors for ALD rather than solutions
Atomic layer deposition (ALD) has been developed for many materials, as can be seen from this overview: https://atomiclimits.com/alddatabase/
However, a search for liquid phase ALD gives less results.
...
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What role does CaCl2 play in a gelation medium?
To produce sodium alginate beads coated with chitosan, following procedure was undertaken:
Sodium alginate was dissolved in distilled water at a concentration of 4% (...) The gelation medium was ...
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Comparing calculated DOS with experimental valence band spectra for oxidized platinum nanoparticles
I've been studying the electronic structure of platinum nanoparticles using DFT and have a question about comparing my calculated density of states (DOS) with experimental valence band spectra.
I ...
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Standardizing alkaline ferricyanide solution [closed]
The ferricyanide method of determining reducing sugars is simple but I need clarity on time of addition of potassium iodide solution. I am unable to observe change in color from yellow to blue. I even ...
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What does the blue square on a volumetric flask mean?
What does this blue square on my volumetric flask mean? I see such squares/rectangles on a numerous other flask brands as well. What is its purpose?
user146152
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Percentage Yield
For the above MCQ question, I took the equation to be
$$\ce{CaC2 + 2H2O -> C2H2 + Ca(OH)2}$$
I then calculated the moles of $\ce{CaC2}$ as 0.7273 moles, which has a 1:1 molar ratio to $\ce{C2H2}$, ...
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How does a conc. electrolyte solution extract water from a organic phase like diethyl ether or ethyl acetate?
In organic chemistry, often, during the last steps of a workup we use concentrated brine solution (NaCl) to "extract" the water from the organic layer, especially when we have an organic ...
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Is nitroglycerin synthesis within human digestive system from eating soap possible?
Could you make nitroglycerin by eating large quantities of pure glycerine soap? A quick google search told me flatus are 59% nitrogen, but I couldn't find anyone else with my exact question (which ...
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Measuring Variables within the Hypothesis
I am performing an investigation on extraction of organic solutes, for example caffeine. With this extraction method, I want to find out whether the organic solvents used actually have an effect, or ...
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If bromomethyl cyclopentane reacts with Alcoholic KOH with Heat. Can this produce some very minor products through E1 mechanism also?
I know that alcoholic KOH with heat will majorly give E2 mechanism products but I want to know if it is possible to get minor products through E1 mechanism here also.
The carbocation generated here ...
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Is it possible to create your own flask/glassware? Has anyone done it recently?
There are alot of flasks/glassware out there, which serve different purposes. Whether thats the Erlenmeyer flask used in titration, invented by Emil Erlenmeyer; or the Schlenk flask used in air-...
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Does a steel pestle corrode while pressing soot?
While experimenting with a few different powders, I noticed the resulting small flakes were ferromagnetic. Then I decided to find out what was the cause: after repeating the experiment with only soot, ...
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Atomization and excitation in AES
AES (atomic emission spectroscopy) is often mentioned as both quantitative and qualitative analyzing method. From this site Atomic Emission Spectroscopy the sources such as flame and ICP are used. ...
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TLC experiment interprentation
I am having difficulty interpreting the results of an identification test involving six different standards (dyes) in an unknown mixture of dyes, using silica gel TLC plates and acetone as the mobile ...
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Synthesizing Cyclotetrazane from Hydrazine and Diazene?
Could cyclotetrazane — a compound with nitrogen atoms arranged in a square configuration — be synthesized? A hydrogen atom would be bonded to each vertex (nitrogen atom):
Could cyclotetrazane be made ...
user145192
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Minimum volume of benzene with percentage yield
The overall yield for the synthesis of N-phenylethanamide from benzene was found to be $35.2\%$.
Calculate the minimum volume of benzene, in $\mathrm{cm}^3$, required to make $10.0\, \mathrm{g}$ of N-...
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Can uncertainty be higher after averaging?
I remember my chemistry teacher said something about how the uncertainty for the average value shouldn't exceed the uncertainty of the uncertainty for the individual values because the reason why we ...
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Need help with synthesis of iron (II,III) oxide (Fe₃O₄) nanoparticles
I am attempting to synthesize iron (II,III) oxide nanoparticles (Fe3O4). I have some iron acetate and have seen some literature where people have synthesized Cu nanoparticles using a polyol process. ...
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Does the side of filter paper matter?
A question has bothered me for quite a long time.
I noticed some filter papers have a smooth side and a rough side. Does it matter (in theory) if I use the smooth side or the rough side for gravity ...
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Effect of particle size on yield of copper acetylide
To avoid pure trial and error, I need some examples of experiments already done with (possibly ammoniacal) aqueous solutions, particles/precipitates of copper (both oxidation states) salts, and ...
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Why cool a reaction down when adding reagents if you're only going to reflux subsequently?
I've seen several procedures using thionyl chloride (SOCl2) to make an ester, where the first step is to add the thionyl chloride to the reagent/solvent on ice or subzero temperature, followed ...
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Trends in pKb for both acetic acid and water
I am trying to rationalise a result that I have recently measured in the lab. I'm measuring the pKb of different compounds in anhydrous acetic acid, using the procedure outlined in this paper (https://...
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About whitish layer that formed on chocolate bar
I noticed a whitish layer on the surface of a chocolate bar that I ate yesterday. I looked at the pack where it was mentioned that,
"Temperature and humidity changes may cause product to develop ...
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What precipitate is formed when a copper coin is dissolved in concentrated nitric acid?
The method being used.
I am currently carrying out a school project where I am determining the copper content of 1p coins. The coins used are British 1 pence coins dated before 1992 as after this year ...
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What could be used to thicken Ferric Chloride solution?
I'm curious if it's possible to thicken Ferric Chloride so I can control it more on a less than horizontal surface ?
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Calculate percent composition from XPS?
I have an XPS graph and was wondering how to calculate percent composition. I do have the percent compositions that were determined from the graph, but I don't know how they were found. For reference, ...
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Testing whether an unknown powder is wheat gluten (at home)?
Last week, I ordered wheat gluten to make seitan. I received some powder and attempted a recipe, which mixes 100g of water with 100g of gluten to form a sticky dough. However in my case, I only got a ...
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Oxidation of Isopropanol by Permanganate in Basic Solution
so I've been designing an experiment where I will explore the effect of isopropanol concentration on the colour change of a solution containing permanganate, isopropanol, and NaOH.
I know that the ...
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How can I refine my method of determining iron content in spinach?
I have begun a chemistry experiment that attempts to determine how iron content in spinach is affected by the length of time it is cooked. Through research, I learned that iron content is often ...
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Question about the differences of white and grey NaH properties
We are having some problems with the next reaction in our lab. As you can see, is the sulfonylation of an indole in which we use NaH (60% dispersion in mineral oil) as a base. This reaction goes with ...
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How to remove hexane from nBuLi
As described in a paper, the authors removed the hexane from the nBuLi solution "under reduced pressure".
I was wondering if anyone had any experience on how to proceed safely with this ...
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Some particles are observed inside the wall of glass vial
Recently, when I use glass vial, some particles are observed inside the wall. These particles are so small and transparent or maybe white-colored, so it is hard to observe during ordinary usage. But ...
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Volumetric flow rate ratio calculation
I'm using two tanks of nitrogen and oxygen and mixing them in different ratios to change the oxygen partial pressure in the system. System is opened to the atmosphere through the venting pipe which ...
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What determines the pressure in the system when the gas tanks are opened?
I have two gas tanks of nitrogen and oxygen. Mixture of gases is created at specified composition and used in the system of interest.
Let's say I want to create an atmospheric conditions in my system, ...
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Could I expect any adverse reactions with this ink mix?
Our newest R&D project for a permanent, outdoor ink includes:
$\pu{25 g}$ of solvent blue 70.
$\pu{25 g}$ of nigrosene.
$\pu{??? g}$ of silver nitrate in a denatured alcohol base.
Several "...
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Is this evidence that solubility of sodium bicarbonate<sodium carbonate?
Someone introduced $\ce{CO2}$ into saturated $\ce{Na2CO3}$ solution, and observed that white precipitate is produced. He therefore claims that $\ce{NaHCO3}$ has less solubility than $\ce{Na2CO3}$.
His ...
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Does manganese dioxide disperse differently in bases than in water?
As part of a project in uni I've been given a task in my chemistry laboratory to synthesise manganese dioxide powders.
I prepared a precipitate of it by reacting manganese chloride with sodium ...
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Surface treatment and current density: electrodeposition of Cd and Ag
I'm currently working on a cadmium and silver electrodeposition project.
Let me explain:
I'm doing electrolytic surface treatment on low-alloy steels as well as stainless steels. At present, we have ...
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Is it possible to create a solid from PVDF solution?
I am working on a project where I am attempting to line an aluminium tube with PVDF. The finished wall thickness is required to be 4mm thick.
I have investigated such processes as injection moulding ...
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The log K value for Cr-EDTA complex is 23, still Cr(III) cannot be titrated directly [closed]
It's related to stability constants.
I don't get the question and where is it taking and wanting to answer.
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