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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21 views

If i dry the starch in oven at 65°C, can it be possible to be set at that temperature? [closed]

I am skeptical as to why most of journals i saw was 50°C for drying starch after isolation of starch from a fruit. But can i set it at 65°C instead?
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10 views

Protocol on gel shrinkage (water loss)

Would like to ask if you can hit me up with some sources or link or suggestion for a protocol that would evaluate gel shrinkage. This is a gel that decreases irrigation flow and after the test, we ...
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1answer
32 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 ...
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48 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 ...
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39 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.
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37 views

Separating gin and tonic after mixing [closed]

Seems unlikely, but is it possible to separate a gin and a tonic water after having been mixed in a glass, without burning off the gin (so in their original forms)?
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32 views

Can the viscosity of a liquid change from day to day? [closed]

If temperature is the same, same meter is used and all other things be the same, can the viscosity change from one sample to another? Thank you Shaun
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16 views

How to switch concentration of 30/70 water/ethanol through dialysis? [closed]

I mistakenly dialysed a preparation in ethanol such that it is now 30% water and 70% ethanol. How do i make switch the water/ethanol concentrations (70% water and 30% ethanol) via dialysis again? The ...
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13 views

About the reaction of Nafamostat [closed]

In this case, doesn't it imine react? I think that only ester part is hydrated though..
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20 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 ...
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1answer
45 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(...
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1answer
84 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 ...
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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 ...
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1answer
25 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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24 views

concentration affect on cell potential

I conducted a galvanic cell experiment and increased the concentration of the anode (Mg) and the cathode was kept at standard conditions. I am unsure about why the cell potential decreased as the ...
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26 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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27 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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43 views

Can I please have some help on an extraction project?

I have a very important senior project due on May 13 and what I am trying to do is extract formaldehyde from DMDM hydantoin in 3 different brands of conditioner and find out which conditioner has the ...
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22 views

Water anomolous behavior [duplicate]

Why water shows decrease in volume when heat from 0 celsius to 4 celsius List item
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2answers
56 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 ...
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1answer
46 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
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1answer
26 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 ...
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3answers
123 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
20 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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13 views

How reliable would commercially available starch be as a standard for an experiment?

I am conducting a student experiment of finding the amylose to amylopectin ratio of certain samples using an iodine colorimetry method. In order to calculate the actual ratios, I need a standard to ...
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17 views

Are there any tests which distinguish between triglycerides and polar lipids/impurities that can be conducted in a high school setting?

I am currently writing a research essay about using a mixed polar (methanol) and non-polar (heptane) solvent system to extract oil from mango seed kernels. One of the difficulties of using polar ...
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1answer
44 views

Usually petroleum ether solvent can be separated from the extract via water bath. Can i use water bath for hexane too? [closed]

Usually petroleum ether solvent can be separated from the extract via water bath. Also usually hexane as a solvent is separated from the extract via rotary evaporator. I don't have rotary evaporator ...
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58 views

The things you wish you would have done before doing a PhD in Organic Chemistry? [closed]

Hello there fellow chemists. I am really interested in doing a PhD in Organic chemistry. I haven't really thought which field I would like to specialize in, but it's definitely on my mind ever since ...
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2answers
65 views

Triple Point of a compound and critical point

Is it necessary for all compounds to have a triple point? Also, how is the triple point determined? Suppose a substance does not have a triple point, so how do researchers agree on the impossibility ...
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1answer
140 views

How do you distinguish ferrocene, acetylferrocene and diacetylferrocene in a NMR spectra? [closed]

I made an experiment where I made a Friedel-Crafts acetylation of ferrocene. Now I would like to know if/how I can distinguish ferrocene, acetylferrocene and diacetylferrocene in a NMR spectra? For my ...
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0answers
45 views

What does Molecular Orbital Theory allow you to predict?

Molecular Orbital theory reveals the outcome when two atomic orbitals overlap. Almost all of the time we draw a Y axis with the notation of energy that can be described using electron volt units (eV). ...
2
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1answer
42 views

How to Test Auto-Ionization of Ammonia

I was wondering how we could test that the auto-ionization of liquid ammonia actually occurs experimentally. The chemical equation is described below: $\ce{NH_3 <=> NH_4^+ + NH_2^-}$ I was ...
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1answer
59 views

How do I calculate weight percent of BaCl2

A $\pu{0.1036 g}$ sample containing only $\ce{BaCl2}$ and $\ce{NaCl}$ is dissolved in $\pu{50 mL}$ of distilled water. Titrating with $\pu{0.07916 M}$ $\ce{AgNO3}$ requires $\pu{19.46 mL}$ to reach ...
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45 views

Could you use All-Purpose Flour as a model rocket fuel?

I'm building a model rocket, and I'm trying to find a good fuel. I've done a lot of research and I know about r-candy and the aluminum-ammonium fuel, but I was wondering, before I made any of these, ...
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1answer
36 views

Best solvent for recrystallization of acetanilide? [closed]

How would you recrystallize acetanilide using ethanol and hexanes? I know this compound is not soluble with the hexanes solvent. But, where would I include ethanol in the procedure? Would I heat up ...
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1answer
43 views

I have contradictory results in a research paper, how do I proceed with my analysis?

I am performing a simple acid-base titration investigating the efficency of different pure antacid compounds, and in my results, I found out that NaHCO3 neutralized the fastest (using a pH by time ...
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0answers
9 views

What are the additional chemicals required to make polyurethane foam more viscoelastic? [closed]

I am currently experimenting with polyurethane forms for a science and research project I am working on. I need to make the polyurethane foam more viscoelastic, almost like memory foam. I am unable to ...
4
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0answers
38 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-...
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0answers
32 views

Will changing the salt in the salt bridge change the voltage produced in a galvanic cell?

I have used zinc sulfate and copper sulfate as the solutions, and used zinc and copper electrodes. For salt bridge I took lithium, potassium, calcium, sodium and zinc nitrates. The results are as ...
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0answers
34 views

Betaine HCl solution at neutral pH

I was trying to make a $2\text{M}$ solution at $\text{pH}\, 7.5$ of Betaine $\ce {HCl}$. I started by weighing out the appropriate amount of Betaine $\ce {HCl}$, added some water and started stirring. ...
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1answer
39 views

How can I find out how much caffeine is in my decaf tea and coffee?

I know that the decaffeination process is not perfect and that it leaves some caffeine. I've looked online and there was a company in 2009 that offered caffeine test strips but they seem to be no ...
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0answers
37 views

Calcium chloride as a drying agent for solutions

I'm aware of the reaction Calcium chloride has with water vapour and how it can therefore be used as a good and inexpensive drying agent but could that be applicable for solutions? For example if ...
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1answer
25 views

Hazard and precautionary statements

Is there a scientific database where one can find all the H and P statements for all chemicals? I would like to avoid using wikipedia but I can't find a database from a trusted source.
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1answer
32 views

Helium container [closed]

Imagine a vacuum flask-like container. If we filled the main compartment with helium and the vacuum compartment with high-pressure gas would helium still escape? Let's ignore the leakage from the ...
2
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1answer
93 views

Reagent notation: meaning of dash(-) and line(|) or slash(\) in reagents

I've seen a lot of reagents which have a slash between two compounds, such as Lindlar's catalyst which is $\ce{H2}$ along with $\ce{Pd|BaSO4}$. I know that the sulphur is a poison here but in general, ...
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1answer
30 views

What happens if you do not allow time for an exothermic reaction to cool down?

I realise I did not give some time for the chemicals (which are releasing heat during an exothermic reaction) to cool down first and instead, I added another chemical substance to the reaction mixture ...
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3answers
165 views

Removing denatured Crystalbond?

I have some water-soluble crystalbond that is attached to silicon and, because of some overheating (to about 150 Celcius) during a final processing step, the crystalbond seems to have charred (white/...
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0answers
55 views

Is there a reusable and safe exothermic reaction

I am looking for an alternative to the sodium acetate reaction used in e.g. heat packs. I need something similiar but that generates more heat, so that I could for instance warm 200ml of water to a ...
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2answers
85 views

pH probe reading greater than 14

Today I was using my pH meter on wastewater samples but the meter was reading values near 14 and sometimes greater, I changed the probe with the spare one and it read well (sure I calibrated before ...
5
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3answers
311 views

Does partially/completely removing solid shift the equilibrium?

For the reaction: $$\ce{P4(s) + 5O2(g) <=> P4O10(s)}$$ Let's say the reaction is at equilibrium, and SOME $\ce{P4O10(s)}$ is removed from the reaction. Will that affect equilibrium? My ...

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