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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14 views

How is pre-consumer cellulose paper distinguishable from post-consumer cellulose distinguishable paper

Looking to write a research proposal for an electron microscopy experiment. Would appreciate any feedback I tried searching a database of journals. I didn’t know which articles would be useful, and I ...
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99 views

Safe chemical reactions to start a campfire

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 ...
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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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9 views

What is the relationship between nonpolar molecules and water? [closed]

What is the relationship between nonpolar molecules and water? help me understand this please
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Temperature relation with concentration and volume [closed]

Q. Standard enthaply change for the reaction of calcium hydroxide with hydrocloric acid was found by reacting $\pu{0.0100 mol}$ of solid calicum hydroxide with $\pu{50 cm^3}$ of a $\pu{1.00 mol/dm^3}$ ...
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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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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
34 views

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

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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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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Bond dissociation energy between phosphate group and deoxyribose in a nucleotide

I need to know the bond dissociation energy between C and O (phosphoester bond) between sugar and phosphate group in a single nucleotide in DNA. I will be really happy if anyone can guide me to any ...
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2answers
58 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
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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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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). ...
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Calculating volume of KI and Ionic strength

A 40.0 ML solution of 0.400 M Hg2(NO3)2 was titrated with 60.0 mL of 0.100 M KI to precipitate Hg2I2 (a) What volume of kI is needed to reach the equivalence point ? (b) Calculate the Ionic strength ...
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What is the concentration of Fe (II) ion in water?

In a redox reaction, 100ml groundwater with 150ml sulfuric acid was titrated with 6.5 x 10-6 mol l-1 concentrated potassium permanganate (IIV). The volume of KMnO4- used is 26.5ml. What is the ...
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1answer
39 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
57 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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Using Gas Chromatography for the Bulk Separation of Gaseous Molecules (Gas Filtration)

I want to modify the typical Gas Chromatography process to focus on bulk separation of gas molecules, without attempting to perform any measurements or data collection. I only have a one-semester ...
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25 views

Homemade alternatives to Benedict's sugar test

I wanted to test some homeopathic medicine (for eczema) for the presence of sugars. I know that they (the meds) are mostly placebos and the actual chemical (I think $As_2O_3$ is in some tablets for ...
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38 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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49 views

Mistakes in an organic chemistry practical [closed]

I'm currently doing an organic chemistry practical. The reactions are pretty basic, material from organic chemistry 1, but it's my first time doing reactions for an organic chemistry lab. What are ...
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1answer
30 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
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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 ...
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34 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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31 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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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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34 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
31 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 ...
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1answer
84 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
163 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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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
74 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 ...
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3answers
301 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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40 views

Why does dissolved oxygen concentration decrease with increasing atomic number of metals?

I am looking at how metal ions ($\ce{Fe^2+}$, $\ce{Ni^2+}$, $\ce{Cu^2+}$, $\ce{Zn^2+}$, and $\ce{Ag+}$) affect the biochemical oxygen demand in water and used the Winkler's method to find out the ...
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26 views

steam distillation vs fractional distillation

I am a high school student and I am a little confused in the techniques used to purify organic compounds, for e.g we study in steam distillation we reduce the external pressure on the compound to be ...
2
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1answer
34 views

Copolymer purity, what does AN / MA / MS mean?

I would like to buy some polyacrylonitrile (PAN) powder from GoodFellow and I have the choice between these two products: AN316010, quality : Copolymer (99.5% AN / 0.5% MA) AN316020, quality : ...
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1answer
36 views

Aluminum electrodes for NaCl [duplicate]

Upon using aluminium Electrodes for a concentrated solution of NaCl, i conducted electrolysis on the solution for nearly 4-5 hours. There was definitely a gas possibly hydrogen being evolved at the ...
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1answer
169 views

NaCl electrolysis with copper electrodes

Considering the aqueous $\ce{NaCl}$ is already concentrated. If we were to use copper electrodes instead of inert graphite electrodes: Would copper react with the evolved chlorine gas to give $\ce{...
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3answers
111 views

How do I prepare citric acid solution (from anhydrous powder) of accurate concentration, given that the solution volume expands when water is added?

I attempted to prepare saturated citric acid solution from anhydrous powder. According to online data, the solubility limit was 59.2 w/w at 20 °C, i.e. 59.2 g citric acid in 100 mL water. To ensure ...
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1answer
69 views

Electrolysis of Nacl with aluminium Electrodes

I conducted an experiment to find out the difference in products/ the final solution whilst using different electrodes. On using copper I obtained a teal blue soluble salt I believe to be $\ce{CuCl2}$ ...
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1answer
49 views

What are the benefits of using zero capillary voltage for discarding fractions in LC–ESI–MS/MS?

In the second episode of The Association for Mass Spectrometry & Advances in the Clinical Lab (MSACL) podcast, namely Getting going with mass spectrometry : Josh learns chromatography (aired 2021-...
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1answer
34 views

Purging submersible with nitrogen

I do a lot of short term ocean field deployments where system electronics are self contained in a submersible enclosure. A new project I'm working on requires a long term deployment in the deep ocean. ...
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0answers
29 views

Free on-line dissociation constants

Is there a decent on-line source for dissociation constants for acids and bases as CRC alternative? This chemistry stackexchange old answer no longer has valid links: Is there an online database of ...
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0answers
31 views

Titanium Dioxide and plastic

How would you recommend attaching a film of anatase to a flat polycarbonate surface without compromising its photocatalytic characteristics? The self cleaning paints that I have seen are generally ...
3
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0answers
52 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 ...
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35 views

Stirring bar cleaning

I have a small question concerning the stirring bars cleaning. I use mine in BOD test wastewater for 5 days and I want to clean them so my question is can I soak them overnight with sodium ...

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