Chemistry - Science topic

Presumably this is an aqueous solution. You do not mention pH of the solution, nor do you mention concentrations. Ferric iron can be an oxidizing agent. These types of reactions are best seen with a Pourbaix (Eh-pH) diagram. These diagrams are calculated using a form of the Nernst equation. They are also called phase stability diagrams. In aqueous solutions, they indicate the predominant chemical species for a given pH, oxidation-reduction potential and concentration. Online, look for:

Wikipedia - Pourbaix diagram

Iron or Iron-Sulfur Pourbaix

Gold or Gold-Sulfur Pourbaix

Sulfur Pourbaix

Biology of Wastewater Treatment by N.F. Gray

Thank you both!

Hi Gregoire,

Thanks a lot for the information and the links! Really helpful!

Cheers,

R

Dear P. Contreras

Interesting! Thanks.

First I would like to ask you a question. I have doubt on the composition of your ink, how uniform?. If your ink preparation is not uniformly dispersed, your loading on GCE may not be uniform. Thus I recommend the following. Amount of catalyst to solvent ration (e.g. m/v), choice of solvent and binding reagents, cleaning GCE strategy and drying systems must be carefully manipulated. For example, if the catalyst added to the solvent system is too large, the distribution/solubility of your catalyst may not be good (try to tune this too e.g. catalyst/solvent ratio 1/1, 1.5/1 and so on). As recommended by other researchers please try ethanol as a solvent and Nafion as a binding agent, here the amount of Nafion also matters, to my understanding should not be higher than 30 μL to obtain uniformly coated GCE. Moreover, if you keep your electrode for long time on air for drying (after loading your ink), your electrode may not be uniformly coated too. Alternatively, you can use 40 or 60 oC oven for short time to dry your electrode with required amount of your catalyst (e.g. 5 μL on 3 mm diameter GCE). Hope this will help you a little.

Because there is a ton of labs out there, that can work with sars cov-2 proteins, but only very few labs that have the clearance to work with sars cov-2 full viruses. You need S3 maybe even S4 to work with sars cov-2.

Dear Asfak Patel thank you for your interesting technical question. It is known that the contact of metallic copper with sodium chloride solutions in the presence of oxygen (air) can lead to corrosion of the metallic copper. Did you check the composition of the precipitate?

For some general information about copper corrosion in NaCl solutions please have a look at the following useful articles:

1. Investigation of copper corrosion in sodium chloride solution by using a new coating of polystyrene/g-C3N4

This paper is freely available as public full text on ResearchGate.

2. Influence of pH and Chloride Concentration on the Corrosion Behavior of Unalloyed Copper in NaCl Solution: A Comparative Study Between the Micro and Macro Scales

(see attached pdf file)

To ensure understandability, reproducibility, and replicability, the research methodology must be clearly spelled out and expatiated upon. In other words, all procedures carried out in a study must be explained in detail in the methods section, leaving no room for whats or whys. The following could render more insights.

PLOS. (2021, February 26). How to write your methods. https://plos.org/resource/how-to-write-your-methods/

USC Libraries. (2021, March 18). Research guides: Organizing your social sciences research paper: 6. The methodology. Research Guides at University of Southern California. https://libguides.usc.edu/writingguide/methodology

Thank you for sharing idea Madhukar Baburao Deshmukh

Good afternoon Mrs / Ms.

What kind of the specific information you probably need ?

Jason Wilt, Because no one knows the degradation products have higher or lower boiling points than the mother amine, I recommend that you use at least two receiver flasks to eliminate both lower and higher bp materials together. Imagine you distill 25 mL, I usually take the first 3 mL and last 1-2 mL each in a same small flask together. Collect the first, low bp portion till the gas temperature becomes constant. Then, you will have a main fraction in a big flask. The gas temperature tends to decrease during the last half of your distillation, heat to keep the gas temp. It's time to stop collecting the main fraction and to change the flask to the drain receiver, if the gas temp. goes down even if the mother liquor is heated. After cooling the whole system to rt, introduce argon or nitrogen to the system, to break the vacuum. Do not dry up the mother flask. Stop the distillation before the mother, heated flask loses all the liquid, because there may be peroxides there. (Dried peroxides are said to be explosive sometimes when they meet oxygen, at high temp. That's why you should cool the system before stopping the pump. You also use argon not air. All of these avoid the danger.) Put a septum cap with an argon balloon to the main fraction, and by a syringe or a cannula, transfer the freshly distilled amine to ampules which are already dry and have argon inside. Close the ampules immediately by flame, and keep them in a dark fridge till you use them, after you warm up to rt. Refluxing with CaH2 for 1 h will usually be done before the distillation. Good luck!

Usually the elements are selected. Those, elements assembled in a group should not have very different parameters (for example, operating voltage, internal resistance). If, for example, during series connection one of the elements has a relatively high internal resistance, then it will limit the entire series, and so on. If you have access to a large number of same elements (for example, in manufarture), then it is not difficult to collect the required quantity for assembly, but with a limited quantity, this can be a problem. In the "professional case", the elements are connected in a circuit using active components to neutralize their differences, both initial and arising during the discharge process.

Dear M. Mozammel Hoque,

I think that Book Organic Chemistry Morrison & Boyd is good for you.

Kind regards

Dear Ahmed Lotfy

Thanks for the response. However, after considering all of the criteria you mentioned, we have to choose a proper journal for our paper.

Let me put the question in this way, what makes a journal better than others!?

In the main question, I gave three examples; could you please choose one of them?

I agree with you Mr. Naimish Kumar Verma.

Dear Lokesh Murali thank you for this interesting technical question. I only found a references in which the combination of nickel selenide with Ti3C2Tx has been reported:

This paper is freely available as public full text on ResearchGate.

Something that has to do with study involving production of nanocomposites for the production of fire resistant parts or shear resistant parts of mechanical equipments.

Production of Biodiesel from non-edible composition of biomaterials by transesterification

Dear Gabris Mahamid thank you for this interesting technical question. As an inorganic chemist I'm not really familiar with this topic, but I can try to suggest to you a few potentially useful articles. Please have a look e.g. at the following papers:

1. Can a single molecule trap the electron?

This article can be freely downloaded as pdf file from the general internet.

2. Functional group dependent dissociative electron attachment to simple organic molecules

This article is freely available as public full text on ResearchGate.

bioinorganic chemistry and applications

I think these attachments can be useful for you

Maybe that helps you: https://typeset.io/formats/elsevier/analytica-chimica-acta/b2233832fb58f1aaa72b712a67a0cc69

I am guessing some kind of click chemistry so some kind of amide or alkyl group that would then be complementary to group on what you attach to.

A safety data sheet (SDS) from one manufacturer attached. This material is very high risk and requires special handling and storage. It does not say on the SDS that it is incompatible with organic peroxides, but in contact, it will release hydrogen gas. I would recommend looking for a safer substitute if possible.

The University of Jena, Germany, and the New York State College of Ceramics at Alfred University, in the USA, are among the most specialized and traditional centers in glass science.

The Federal University of Sao Carlos, in Brazil, also offers very equipped facilities, if you prefer a tropical country.

Of course, there are a lot of other good institutions... it depends on the subject you are interested in within the topic of glass chemistry. For example, if you want to research Bioactive Glasses, the Imperial College London has nice researches in this field.

The best way is to measure X-ray or electron diffraction accomplished with photoluminescence. It will give both insights into the nature and the quality of surface improvements.

Nobody forbids anyone to look for and use other relationships of rate constants on temperature than the Arrhenius equation. In design, it does not matter whether the equation/function used has a physical meaning or is merely an empirical equation. In science, however, one should not assign physical meaning to equations and thier parameters that they do not have. Unfortunately, this is a common procedure.

PBEsol stands for "PBE functional revised for solids", it is an evidently better choice for calculating lattice constants of solid. PBE is preferred over PBEsol for general-purpose calculations.

Dear Daniyal Ahmed just in case that this question is still of interest to you: The article cited below contains a detailed description of how to make oleum in the laboratory:

Personally I would suggest to buy oleum from commercial sources as it is an industrial product manufactured on a large scale.

Dear Talal Ashraf there are two potentially useful article on this topic available as public full texts right here on RG:

1. Predicting Feasible Organic Reaction Pathways Using Heuristically Aided Quantum Chemistry

2. Neural networks for the prediction organic chemistry reactions

Also, see the following RG links.

Follow

Hi Leonard, I would suggest you search review articles on your topic first, journals like the Review of Educational Research could be a good start to find the foundation studies for your proposal. Good Luck with your research proposal!

-Tingting

Dear Ethan,

There is a similar question which were posted in the research gate forum. This could answer your question. Please see the following link

Best wishes

Xuhua

Since the pKa's of acid and base are far apart, you probably start with a near neutral solution before you add the extra weak base. Then you pH goes up into the alkaline area.

Normally you prepare a buffer by either using a weak acid and adding about half of its concentration of a strong base or vica versa. I do not understand that you call a mix of a weak acid and a weak base a buffer.

What is the purpose of your 'buffer' ?

Sodium metabisulfite (Na₂S₂O₅) dissolves in water as sodium bisulfite: Na₂S₂O₅ + H₂O → 2NaHSO₃. Sodium bisulfite is converted to sodium sulfite (Na₂SO₃) by

NaOH. The solubility of sodium sulfite (Na₂SO₃) in the alkaline solution may have been exceeded due to the common-ion effect, as Na⁺ is also contributed by the NaOH aq. sol.

Ok sir !

Thank you and will update you too..

Dear Dr. Shafeek Buhlak ,

I suggest you:

-Advances in Nanotechnology and Its Applications

Ahmad Tariq Jameel and Abu Zahrim Yaser Editors

Publisher: Springer Verlag, Singapore

Publication year: 2020

ISBN 10: 9811547416

EAN: 9789811547416

-Nanotechnology

Paresh Chandra Ray Editor

Publisher: Nova Science Publishers Inc

Publication year: 2018

ISBN 10: 1536138894

EAN: 9781536138894

My best regards, Pierluigi Traverso.

Thanks for the multiple replies.

The probability of pick-off annihilation in positronium (Ps) is primarily due to electron density, as Rüdiger Mitdank has pointed out. It is described by the overlap of the positron and electron wave functions. However, in practical terms, it is not determined by that alone, but is also affected by various environmental factors. In this discussion, I would like to get into these factors.

For example, water and many other liquids expand as their temperature rises. Since expansion decreases the molecular density (electron density), it is assumed that the higher the temperature, the longer the Ps lifetime. However, this assumption is not true. In fact, the lifetime of Ps is shorter in warm water than in cold water.

Similarly, the relationship between Ps lifetime and pH is not easy to estimate. Therefore, we should base our decisions on experimental data.

Most of the basic Ps chemistry was done in the 1960s and 1970s. In those days, the resolution and stability of measuring instruments were not as good as they are today, and the use of computers was limited. Straight lines were drawn with a ruler on hand-drawn one-log graphs. Therefore, the environmental factors that were reported to be "independent" at that time may or may not be due to the lack of measurement accuracy. As the application of positron science to medicine has progressed, motivation to revisit some of the issues has arisen.

I hope somebody will continue to let us know if you have any information on the relationship between pH and the lifetime of Ps. Thank you very much for your time.

Try to reduce pH of the solution. May be it will help.

Kafia Oulmi Thank you for the recommendations.

Thanks, Jukka. I've gone with ethanol to be safe.

Timothy Braun I am using MFiX for several months and I saw a Barracuda VR. But some reasons (like a budget :) ) I couldn't use a Barracuda.

Each software have different pros and cons for MPIC schemes. Firstly, MFiX is open-source and you can change everything that you want (like a user-defined-function). Also, MFiX has some different discretization schemes, solver types, etc.

Btw, Turbulent solvers are different. I'm working on turbulent case and chemical solvers these days. It seems Barracuda is beginner user friendly, but need to time for learning advanced things for MFiX.

Thanks a lot, it was interesting to read it, but it still did not answer my question about OH-. I feel more and more that nobody knows. One option could be that the OH- goes into the tissues but it is silent about it because it is very difficult to measure. I cannot really see any other solution.

If you want to solve your problem as it appears in the image, I recommend using an equation of state for the enthalpy departure.

I also recommend the following articles:

-A computationally effective formulation of the thermodynamic properties of LiBr-H2O solutions from 273 to 500 K over full composition range

- Exergy calculation of lithium bromide-water solution and its application in the exergetic evaluation of absorption refrigeration systems LiBr-H2O

-Thermodynamic Evaluation of LiCl-H2O and LiBr-H2O Absorption Refrigeration Systems Based on a Novel Model and Algorithm

-Mathematical Model of a Lithium-Bromide/Water Absorption Refrigeration System Equipped with an Adiabatic Absorber

Dear Huyen Tran Dang to my knowledge the formation of difluorosilane, SiF₂H₂, cannot be explained by the reaction of SiF₄ with HF. The latter two compounds will react under formation of H₂SiF₆ (see e.g. the link cited below). I think that the formation of SiF₂H₂ can only be explained by the presence of elemental hydrogen, H₂.

https://brainly.in/question/1115388

Hello Mr. Hajipour

"N" refers to a molecular nitrogen presents in a defined concentration of a molecule or ion. You can find it out by multiplying the molecular weight ratios.

In your example if N in the form of nitrate (NO3^-) is 10 mg, then the concentration of nitrate molecule will be 10 mg N*(62 mgNO3/mmolN)/(14 mgN/mmolN), i.e. 44.28 mg NO3^-.

Same concept is valid for any other atoms and molecules.

Regards

In all metabolic processes in nature, electron transfer takes place at the molecular level. Two fundamental atoms in all living entities are oxygen (O) and nitrogen (N). In direct combination, they form NO, which is one of the most crucial biomolecules because it has a free electron ("free radical"). It is part of a universal communication system in biologicals cells.

If we go one level of abstraction higher, we find the amino (NH2) and the carboxyl (COOH) groups. In the carboxyl function, the electrons can migrate from one O to the other via the C atom (mesomerism). Thus, the H atom can easily migrate to the "partner" NH2 - the electrons are "free" and can participate in biological processes.

It is also why phenols, especially polyphenols (green tea EGCG, resveratrol, quercetin), are biologically very active. If both functional groups occur within one molecule, we have one of nature's most essential building blocks, amino acids.

With more atoms and larger molecules, the electron transfer becomes more complicated, but it can explain almost any drug's mechanism of action. It is perhaps interesting to note that electron transfer within biomolecules is sometimes completely different from what we know from the chemical laboratory.

That is why "free radicals" in the body are not generally harmful but vital.

SUMMARY

In summary, it is one of the most important functional groups in nature. That is the reason why it occurs as a functional group in so many drugs.

Attached you will find a link to a paper describing the effect of some functional groups in drugs.

But ICP-OES is a costly instrument and therefore available in a few research laboratories of third world countries.

Hi Simon, I have used many cleavage cocktails and scavangers for peptide cleavage. My opinion: The cocktails aren't that stable, especially the TIPS and thioanisol. Maybe one week is fine if you keep it in the freezer. I would recommend to start with a fresh cocktail each day for best results.

Dear Prof James

thanks for sharing your nice answer

Heating is to be done

I only want to get rid of the trapped gas and bubbles first

Thanks for your answer !

5%Ti 1%B add as a master alloy of Aluminum in wieght ratio 100:1 Kg

I think the main established routes employ biochemical catalysts. I've been working in this area for more than 7 years and I haven't heard of any new developments in solids catalysts for the saccharification of lignocellulosic biomass. Enzymes are very specific and productive towards breaking glycosidic bonds. Enzymatic reactions also require mild reaction conditions such as low temperature and mildly acidic pH.

Nice question

Good question

Dear Sweety Rani, to a very low extent because of the hindrance of two bulky neighborhood benzene rings. Chain stiffness and compactness reflected by high Tg limit (almost excluded) diffusion at ambiant conditions. These are the main reasons behind PES chemical modification. My Regards

لم استطيع التحميل

Mr. Solis,

What you shall synthesis in your home-lab? Something for the market in United States?

Have you decided to compete with Colombian home laboratories; and reagents in Mexico are freely available in stores?

we have ZnO powder, how can i coat on glass or ITO substrate

The experience of the development of science shows that the quality and significance of a scientific discovery and its usefulness or harm for human civilization are inversely dependent on any expectation, be it the expectations of the entire scientific community, and even more so the expectations of a "non-professional" society. For example, it is known that the great Rutherford, who discovered the atomic nucleus, believed that his discovery would have no practical application.

I think you mean to say the amount of emission by pharma sector. There is no study available but pharma industry is one of the major contributor of pollution. Pharma market is 28 per cent smaller yet 13 per cent more polluting than the automotive sector

The answer to this can be very subjective. It is like saying how much of polution comes from airplane pilots. I have no data to support this but let's try common sense: most human waste comes from factories, mining, transport, institutions and households. There has to be a line between processed and unprocessed waste. If your question meant chemists in academia then I would say it is negligible (<<1%). But if you want to highlight it based on potency, that number can increase if you take subcategories of chemicals only produced in lab.

I may need more information to answer your question. However, you may read my paper to get an idea of how molecular motors and switches work.

1. Proton‐Gated Photoisomerization of Amino‐Substituted Dibenzofulvene Rotors

2. Synthesis and Photoisomerization of Substituted Dibenzofulvene Molecular Rotors

We discuss this aspect in detail.

We have used this technique for one drug and confirmed stability for 12 months at 20C but it is impossible to generalise. Stability will have to be established for every individual drug and set of conditions I;m afraid

.

Teaching and research jointly

Dear Eric Täuscher here is another interesting paper by the famous henry Gilman entitled "Color Tests for Some Organolithium Compounds"

this depends on which type of ligand used

Dear Gang Zhu

The applications of chemo-mechanical coupling discipline are going on for the time being into two directions that covering by materials research and development activity:

Designing and manufacturing a multifunctional components that characteristics in a variety of applications e.g. artificial organs.

Highlight the mechanism of material degradation and failure case study e.g. high temperature oxidation process.

Now, in the case of high temperature oxidation the mechanical coupling with the oxidation chemical reaction results in stress generation in the oxide scale formed which in turn affects the chemical reaction rate and the diffusion process of the reactants and therefore, the process become a complex chemo-mechanical as the stress is diffusion dependent during the oxidation and the oxide growth is stress induced.

In other hand, the story may be different with the hydrogel coupling behavior as external mechanical load can induce redistribution of ionic concentration, while a chemical stimulus lead to swelling or shrinking of the hydrogel.

So for this multi-field coupling behavior in a medium, there are many approaches that have been proposed by many researchers leading to a bundle of knowledge for the same coupling behavior .Thus, I think that makes the topic appears as foggy to understand by many of the followers.

I hope the above contribution is helpful.

Best regards

Thanks to all

Since the emergence of digitalization, we are moving more and more towards “a machine for every process or problem” This is good for achieving efficiency and effectiveness and for large unimaginative technology companies that follow a marketing strategy as ”convenience suppliers”. However, in school pupils should learn fundamentals of processes. In micro chemistry there is basically no difference between traditional chemistry except scale. So, if you can’t see particles you may be able to precipitate, to concentrate, to color, to separate in order to make them visible. Under Corona condition you don’t have to do that in a lab – you could ask kids to do that at home in their kitchen with household equipment.

I am also amazed that in high-school environments pupils are not taught about the most important purification-separation technologies. They grow up without understanding that today we separate any mixture into its individual particles or molecular components. And so, they do not understand that we should not cheat or lie because we can trace any evidence say in biology, forensics, analytical chemistry etc. The excuse of “too expansive” we are currently addressing by creating a low-cost chromatography instrument for schools. (see https://www.chromatographyshop.com/product/scholar-lc-system/ ) We are preparing easy to handle instructions and experiments that are relevant in our time and exciting. The idea is to get the pupils to do the experiments. Environmental education is best done by involving scholars to change the world.

Dear T.J. Samojedny ,

Indeed, a good point. I see papers like:

Cole, J. C., Smith, M. W., Penn, C. J., Cheary, B. S., & Conaghan, K. J. (2016). Nitrogen, phosphorus, calcium, and magnesium applied individually or as a slow release or controlled release fertilizer increase growth and yield and affect macronutrient and micronutrient concentration and content of field-grown tomato plants. Scientia Horticulturae, 211, 420-430.

https://www.sciencedirect.com/science/article/pii/S0304423816304691

were the ‘formal’ notation is ‘loosely’ used. I think everybody understands that when talking about Mg content in these type of studies is actually Mg2+.

Personally, I would use Mg2+ as much as possible or talk about Mg ions, but I can imagine that in other disciplines other notations are tolerated or simply more costume.

Best regards.

1. C1*V1 = C2*V2

200 mg/ml * V1 = 40 ug/ml * 300 ml, or V1 = 0.06 ml (of ampiciline)

2. If you mean 75 ml is the total volume of final medium, then:

C1 * V1 = 75 ml * C1/50

V1 = 75/50 = 1.5 ml (of bacteria)

I totally agree with you

INNATE Pharma (Marseille, France)

It varies from school district to school district but typically qualified Chemistry, Physics and other sciece teachers are hard to find. When they get somebody they try to keep him/her and if they can't find anyone the teacher and students learn the subject together.

Dear, did you characterized the product? This reaction requires a rigourous anhydrous conditions. May be the solvent is not dry enough. If this is the case, the NCO formed will immediately converts to an amine. My Regards

You can use Soxhlet or Soxtherm to separate oil by solvent extraction process and Hexane/ Methanol/ Acetone as a solvent.

Hello,

Teaching of chemistry in Argentina is almost similar to other part of the world.

Thank you

What exactly you need? Frame a valid querry.

I think the public perception about chemistry and chemicals is negative due to environmental education. Nevertheless, drugs, plastics, textiles, dyes, fertilizers, pesticides etc. are still purchased and used on large scale.

Dear Philipp Selenschik, the best way is to get experimentaly the average MW via viscometry, GPC, or any other available technique at your place. My Regards

Yunus Shukor thank you very much for your help! We will try to find some mechanism to separate plastic from sea life :)

Also check https://blog.v-hr.com/blog/how-autonomous-cleaning-drones-could-save-the-ocean?hs_amp=true

From my long experience of teaching, the researchers who have rich researching CV usually have poor teaching records and vice versa. That is especially true for the universities that haven't a sufficient researching budget. The reason behind that is that researching needs more time at the expense of teaching.

Rob Keller Wolfgang Schechinger Thank you both for your help! It clears it up so much. The general chemistry of it was indeed straightforward, but I had trouble with what will happen to the hydrate once dissolved in water.

I guess that the hydroxyl-terminated polymer will have a strong bond with the plasma treated PDMS. Because after the treament with oxygen plasma, PDMS surface will be covered by a lot of hydroxyl group.

Specific Gravity is calculated based on the weight of a substance dissolved in particular volume divided by weight of an equal volume of water. You can try this method to calculate the specific gravity of a substance.

The ETL must satisfy specific requirement to function properly:

- The electron concentration must be as high as possible.

- The mobility of electrons must be also as high as possible.

- The energy levels must must match those of perovskite.

The lumolevel of the ETL must be lower than the conduction band of the active layer.

What is the effect of the molecular weight on these parameters must be known to judge which material alternative will be more suitable.

I would propose that you pragmatic on the issue and make planned experiments with the materials to evaluate it. Or you can measure the electronic properties of the material to assess its properness.

Best wishes

Nor Maisurah so what is your question?

regards,

GB