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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3
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0answers
42 views

How to do a capacitively coupled electrode?

I have an AUTOLAB potentiostat: working electrode (WE, Pt wire), counter electrode (CE, Pt wire), reference electrode (RE, Ag/AgCl solid state). I would like to capacitively couple the potentiostat ...
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0answers
29 views

how is glow in the dark phosphorescent made? [closed]

what makes the glow more brighter than ever?
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37 views

Chemistry Equations [closed]

How do I know what the equation of a reaction is without knowing what the products are? Am i meant to do trial and error and just guess? Eg: When 3.4g Pentane was burnt in excess oxygen, 165kJ of heat ...
3
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0answers
46 views

Purification of Buchwald-Hartwig amination

I am conducting a synthesis involving Buchwald-Hartwig amination. I use $\ce{Pd2(dba)3}$, $\ce{P(o-tol)3}$, and $\ce{Et3N}$ as base. In many proposed mechanisms, they often omit the precatalyst. I ...
4
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2answers
60 views

Should I do solvent extraction for Buchwald–Hartwig amination?

I am conducting a synthesis involving Buchwald–Hartwig amination. Catalyst is $\ce{Pd2(dba)3},$ ligand is $\ce{P(o-tol)3},$ base is $\ce{Et3N},$ and solvent is toluene. Image below is the proposed ...
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16 views

Question about Oxygen Managment [duplicate]

I am working on ideas for a more hard Si-Fi, and I am wondering through what processes one could theoretically take the carbon dioxide we breath out and break it down into Carbon and Oxygen. I am ...
0
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1answer
39 views

How to thermally insulate beaker glass on hotplate?

I bought a magnetic stirrer with a hot plate almost identical to this one. I am trying an experiment where I need to heat the beaker/mixture to about 100 degrees C. However the mixture/beaker is ...
1
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0answers
47 views

Is it possible to run column chromatography in reversed phase?

I'm conducting a synthesis involving aza-crown-ether. Whether aza-crown-ether acts as a base or not is unclear, but when I do TLC using dichloromethane/methanol, it hardly goes up. (see image below) ...
2
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0answers
24 views

In cation analysis, can reagents of higher group precipitate lower group cations?

My teacher told me that Al$^{3+}$ and Zn$^{2+}$ hydroxides are frequently precipitated together and that is why we have to be careful about the concentration of base (NH4OH) added. Does this mean that ...
1
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0answers
38 views

Leakage during Celite filtration

I'm conducting a synthesis involving crown ether and Pd catalyst. In many papers, prior to column chromatography, they filter crude mixture through a Celite pad. I tried to, but leakage of Celite ...
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0answers
22 views

Why does iodine to give off so much vapour? [duplicate]

It is reported that when placing iodine in a breaker and letting it sit, over time the iodine will slowly give off a large amount of vapour. The question is why does it give off so much vapour. I was ...
2
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0answers
18 views

Is there a way to experimentally determine if a copolymer has a random monomer distribution or a blocky monomer distribution?

I prepared a styrene-butadiene copolymer with a polar modifier. The expectation is that the copolymer is "random". Is there a way to confirm this using standard characterization techniques?
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1answer
43 views

Using samples in titrations

I've never done an experiment before. So, the methodology provided in this pdf is quite confusing. Link to the pdf: https://www.canterbury.ac.nz/media/documents/science-outreach/vitaminc_iodine.pdf So,...
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0answers
31 views

What's the right way to prep anhydrous potassium ferrocyanide from potassium ferrocyanide trihydrate?

Orgo student here. I've got some potassium ferrocyanide trihydrate I tried dehydrating with no success. I put 20 g of potassium ferrocyanide trihydrate into a 30 mL crucible driven up to 150 C for 2 ...
1
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1answer
59 views

How can I filtrate Pd2(dba)3 and P(o-tol)3? (Celite filtration failed)

I am conducting an organic synthesis involving Stille coupling, using $\ce{Pd2(dba)3}$ and $\ce{P(o-tol)3}$ as catalysts. Reaction solvent is toluene in which the catalysts also dissolve. Many texts ...
2
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0answers
42 views

what does Area(A) in Randles-sevcik equation refer to? geometrical area of electrode or electrochemical active surface area/

In the Randles-Sevcik equation, $$i_p = 0.4463 \ nFAC \left(\frac{nFvD}{RT}\right)^{\frac{1}{2}}$$ we have an area $A$ in the formula. is this the electrochemically active area or geometrical area? ...
5
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42 views

Why is surface tension of water decreasing as sodium chloride concentration increases? [duplicate]

For my IB chemistry IA, I am measuring the impact of salinity concentration on the surface tension of water (i am using distilled water). My hypothesis is: As the concentration of salt increases, ...
1
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1answer
50 views

Why d and s orbitals overlap even when there is considerable difference in their energies?

In my grade 11 chemistry NCERT textbook, its written that hybridization happens when orbitals of almost same energy overlaps. But S orbital and D orbital have significant difference in their energies. ...
4
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1answer
67 views

Does pH gets affected by pressure? [closed]

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 ...
-2
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1answer
66 views

How to make plasma in microwave (without grapes please)?

So, I have my School Science Fair next month. We are working in teams of five with one 7th, 8th, 9th 10th, 11th and 12th grader. We were planning to make plasma in microwave but the grape method just ...
7
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4answers
244 views

What's the purpose of significant figures in measurements?

I have read about significant figures in my chemistry and physics books, but none of them pointed out the significance of the significant figures. Searching the Internet I found two possible answers: ...
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2answers
87 views

What would happen if the alpha particles directly hit the electrons in the gold foil in Rutherford's experiment? [closed]

What would happen if the alpha particles directly hit the electrons in the gold foil in Rutherford's experiment? Would it get ionized or is there no probability of such a thing happening ?
2
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1answer
59 views

Is it possible to filter Stille catalysts using syringe filter?

I'm conducting an organic synthesis involving Stille coupling. Stille coupling uses $\ce{Pd2(dba)3}$ and $\ce{P(o-tol)3}$ as catalysts. Both catalysts dissolves in toluene which is the solvent of my ...
2
votes
1answer
51 views

Can the paper in thin layer chromatography be any type of paper?

I'm doing a chemistry chromatography lab that wants me to recreate anything I want. I decided to measure how far a pigment goes in each color for the same brand, but I'm stuck at the paper part. I ...
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0answers
27 views

Thickness of proton exchange membrane (Nafion)?

I am looking into using a proton exchange membrane for a bio-energy cell experiment. Previous scholars have been using Nafion as a PEM to place between the anode and cathode (air-cathode). the ...
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1answer
65 views

How to heat up a barrel drum? [closed]

I am experimentalist, and I am unsure on how to proceed about a question I have for an experiment. In the experiment, I would like to heat up a drum barrel like: It is made of HDPE, and I would like ...
0
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0answers
16 views

Can ethanol and heat during distillation cause degradation/dissolution of vinyl tubing leading hot vapors of the distillate to the condenser?

I'm a chemist and a qa lab, and we occasionally test herbal remedy products from one of our customers for alcohol content using a distillation, then using the specific gravity of the distillate to ...
0
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1answer
196 views

At which temperature does a concentrated aqueous solution of sodium chloride begin to boil? [closed]

We know, solutes dissolved in water increases the boiling point of water. This question is an MCQ. The options are 96,99,100,104 degree Celsius. The correct answer is 96. Why? If the boiling point ...
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0answers
29 views

Why is Retention factor for Iodide greater than Bromide?

I did a separation of Bromide and Iodide ions using paper chromatography technique for 0.3% solutions of Bromide and Iodide of sodium. I got the Retention factor equal to ~0.71 for Iodide and ~0.47 ...
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-...
3
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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 ...
1
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1answer
32 views

Three Phases in TFM test instead of two

I am currently trying to perform the Total Fatty Matter (TFM) test on soap and for some reason I am getting three phases instead of two. The surfactant used is SLES and other reagents include hot ...
1
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0answers
21 views

Reason for three phases in total fatty matter test on soap [duplicate]

I am currently trying to perform the Total Fatty Matter (TFM) test on soap and for some reason I am getting three phases instead of two. The surfactant used is SLES and other reagents include hot ...
2
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2answers
107 views

How to find the angle of emission of an X-ray during impact of accelerated cathode rays?

X rays are produced when accelerated cathode rays strike a metal target or a metal anode. How can we find the angle at which the X-ray is emitted from the metal anode or the target when the cathode ...
-4
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1answer
64 views

Practices while using a boiling tube

When using a boiling tube to boil a liquid, I am frequently advised to move the boiling tube in and out of the Bunsen flame and when the liquid starts to boil, remove the tube from the flame for a few ...
0
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1answer
46 views

Synthesis of 1-naphthaleneacetic acid: Methods

I am trying to synthesizing 1-naphthaleneacetic acid from naphthalene and monochloroacetic acid. I found some patents and papers, and I have tried to synthesis but the yield is low. I used iron powder ...
0
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0answers
57 views

How can I weigh the compound that melts at room temperature?

I am conducting an organic synthesis experiment involving 2,3,5-tribromothiophene. The melting point of 2,3,5-tribromothiophene is about 25-28 ℃, so it melts easily during weighing. Whenever I weigh ...
1
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0answers
43 views

Procedure for laboratory synthesis of tertiary amines [closed]

I am having difficulty finding a procedure for making tertiary amines in the lab, any is fine but I am specifically interested in tributylamine.
3
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0answers
23 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 ...
0
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1answer
65 views

Detection of sulphide in solution also containing sulphate

Question: The reagent(s) that can selectively precipitate $\ce{S^2-}$ from a mixture of $\ce{S^2-}$ and $\ce{SO4^2-}$ in aqueous solution is(are): (A) $\ce{CuCl2}$ (B) $\ce{BaCl2}$ (C) $\ce{Pb(...
4
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1answer
130 views

Can we use silver nitrate to distinguish between chloride and carbonate salts?

Initially, we are given a solution containing two salts, they can be either carbonate or chloride salts (we do not know their composition initially). Generally, $\ce{AgNO3}$ is used as a confirmatory ...
3
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0answers
18 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 ...
5
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1answer
35 views

Carbon 11 radiolabeled inhaled Beta-2 agonist or corticosteroids, is it possible?

Background Positron emission tomography (PET) is a highly sensitive imaging modality that can provide in vivo quantitative information of biological processes at a biochemical level. PET relies upon ...
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0answers
31 views

Measuring Cylinders — small or big?

My teacher often recommends the usage of a smaller/more narrow measuring cylinder over a larger one while performing experiments but why is that? Does it help in accuracy in any way?
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0answers
42 views

What is the literature value of the activation energy of the reaction between iodate and bisulfite?

I explored the Arrhenius equation using the reaction between potassium iodate (containing the IO3- iodate ion) and sodium metabisulfite (bisulfite ion), however I can't find a literature value to draw ...
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2answers
61 views

Enthalpy vs. delta enthalpy

I haven’t really found a clear answer. Enthalpy is measured as the sum of internal energy (kinetic and potential energy) and pressure times volume. However, I don’t really see the value of measuring ...
0
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1answer
52 views

How to make silicic acid, potassium silicate or calcium silicate?

I am a student of tropical agriculture. I am taking the class of agronomic chemistry and plant nutrition. I want to make use of silicate source I have at home for e.g. zeolite, wood ashes, ...
2
votes
1answer
27 views

Diffusion of multiple gases at once

Graham’s law of diffusion states the rate of diffusion between two gases is inversely proportional to their molar masses. Now, this is helpful when we are focused on two gases. But that is rarely the ...
1
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3answers
135 views

Safe chemical reactions to start a campfire [closed]

I'm looking for a way to start a small fire electronically with widely available chemicals. It would be great if they are safe to use with metals (not necessarily). But the biggest requirement is that ...
2
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0answers
25 views

Is there a known value for the molar extinction (absorption) coefficient for amylose and amylopectin iodine complexes?

I am doing a colorimetry experiment with starch, and have a theoretical model based on Beer's law. To solve it, I need a known value for the molar extinction coefficients of amylose and amylopectin ...

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