Science topics: Chemistry
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Chemistry - Science topic

Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds.
Questions related to Chemistry
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Greetings.
During experiments and reading about MOFs, I found something that is strange to me.
For instance, in MIL-100/101, the secondary building units (SBUs) are [M33-O)(O2CR)6L3]n+/m−, while some reports claim that their as-synthesized MOFs are constructed by [M33-OH)(O2CR)6L3]n+/m−.
Both of these SBUs are 6-connected, topologically they are the same. But from the aspect of chemistry, O-center or OH-center makes a lot differences especially in the valances of related metal ions (for instance, Co2+ or Co3+, Fe2+ or Fe3+, etc.) and in the counter ions in pores/L sites (like dimethylammonium ions, coordinated fluoride ions).
I am wondering, is there any way that we could determine the actual form of this 'center' ?
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Locating a single proton from e density difference maps would be tricky to say the least. Structurally, μ3-O2- will be planar, whereas μ3-OH- will be pyramidal.
There are physical techniques like magnetometry and EPR that may help you assess the spin of the metal ions if they are magnetic.
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Hello fellow chromatography experts. This is a subject for a fruitful discussion that everyone can benefit from. To make it helpful, I appreciate that you provide a reference to support your preference.
The topic is: When to use Linear fit for the calibration curve, and when to use a Quadratic fit? Is it analyte-dependable, which means the quadratic fit is reserved for a group of analytes sharing a specific chemistry for instance? Or is it a technique-dependable, which means if the technique is Gas Chromatography then a linear fit should be used, and so on? Or is it a column-dependable, you know the drill!
The second part of this discussion should be about the proper weighing power when making the fit. Again, is the weighing power is dependable on any factor I mentioned earlier or did not mention at all, or is it just a user preference?
Let me add to these two topics another one. If you calibrate your instrument with a five-point calibration curve, and after a number of injections you decide to inject a control sample to check your instrument's response. What percent deviation from the initial calibration you would accept before recalibrating?
Let's discuss these topics and make our discussion a good reference for beginners in the chromatography field.
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Please read my responses again. No opinion(s) are given except that your question does not address the features available in most research grade chromatography software. Curve fits can not be categorized into just two types, linear and quadratic. You make it sound like we must choose only between these two choices. Are you using a software package that limits you to only 2 types of curve fits? If so, that may pose a problem for some sample types. Why do you limit this to just two curve fit types when in fact, several types may be needed for some sample types (e.g. the n-polynomial fits are useful too)? Some real world samples require far more than 2 (proof can be found from experience using many types of specialized detectors and different compounds. The literature is filled with examples, but the easiest way to see examples would be to search for HPLC-ELSD based methods). To ask 'why' instrument vendors include various curve fit options in their software does not address an actual need, but a perceived one. IN the case of curve fits, the DATA determines which fits are appropriate (not the vendor) and we are fortunate that so many chromatography software vendors have continued to include and offer many different types, similar to what is found in good quality statistical software packages.
I never stated that Linear output should always be used. I stated that you should use the best fit, the best formula that describes the data. This is not an opinion, but the mathematical model used to describe a data set.
Regarding calibration of mixtures. This has nothing to do with them all coming in the same vial. It is about measuring the response obtained from EACH sample or standard (which is not related to them being in the same vial. That is concentration, not response). We calibrate and fit points based on response. Two different proteins with the same concentration in solution can have two different responses (e.g. depending on the detector used), and this is why we measure it, record it and then plot it for each compound.
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Hello Good day i am a undergraduate student, please help me to have a topoc of my research proposal about organic chemisty. Thank you so much.
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I recommend a Research proposal about organic chemistry for you :
1- Synthesis heterocycles compounds
2- Synthesis Nanocatalyst
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according to you what are Hot problems currentlyworld is facing? And what solutions you would suggest to solve them?
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  1. Now, I agree with prof. Madhukar Baburao Deshmukh.
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Much has been said about the differences between physics and mathematics, but less attention has been paid to the differences between physics and chemistry.
The question is, where does physics and chemistry work?
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Thank you.
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chemistry webinar certificates
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The research knowledge shared during the webinar is much more significant .It also extend your CV and during promotion it will be helpful.
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Hello everyone,
I have 5 Samsung 21700 - 50 E (NCM chemistry) cells. I want to do basic charge and discharge by connecting it in series. Does anyone know if there is a cell holder available online for single cells? Or how to connect these cells and make contact?
Thanks in advance
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Also, weld[1,2] two, independent, wires on each battery[2,3], one (1st) wire for i, and one (2nd) wire for V.
1. or even solder, if a(ny) welding technique is not available, in the Lab.
3. Tailoring micro resistance spot welding parameters for joining nickel tab to inner aluminium casing in a cylindrical lithium ion cell and its influence on the electrochemical performance https://www.sciencedirect.com/science/article/pii/S1526612519304347
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Dear Colleagues,
I’m pleased to inform you that open access journal /Catalysts/ (ISSN 2073-4344, Impact Factor: 3.444) is planning to publish a Special Issue on the topic of "Trends in Catalytic Advanced Oxidation Processes". The submission deadline is 30 March 2020.
This Special Issue is dedicated to novel achievements in the field of catalytic advanced oxidation processes. The contributions should be related to the listed topics:
· Catalytic processes in water and wastewater treatment
· Developments in Fenton-like AOPs
· Activation of Persulfates for AOPs
· Formation of sulfate radicals
· Catalytic cavitation-based AOPs (hydrodynamic cavitation and acoustic cavitation)
· Sonocatalysts
· Catalytic ozonation
· Photocatalysts—including visible light and UV applications
· Catalytic wet air oxidation (CWAO)
· Catalytic–electrochemical AOPs
· Carbon catalysts for AOPs
· Nanocatalysts
· Risk of by-product formation during water and wastewater treatment
· Developments in process control of catalytic AOPs (analytical methods, chromatographic, and spectroscopic techniques)
· Methods of catalysts characterization
· Post-process assessment of effluents toxicity
· Application of nanobubbles in AOPs
· Economic analysis of catalytic AOPs application and catalysts life cycle assessment (LCO)
· Industrial catalytic wastewater treatment
· Modelling and optimization of catalytic processes
· Green chemistry aspects in catalytic water and wastewater treatment
Detailed information regarding this issue, please follow the link below to the Special Issue website at: https://www.mdpi.com/journal/catalysts/special_issues/catalytic_aop
By publishing with Catalysts, you will take advantage of the following attributes:
*Fast Publication*:
First decision provided to authors approximately 13.4 days after submission; acceptance to publication is undertaken in 5.5 days (median values for papers published in this journal in the second half of 2018).
The papers will be processed immediately upon receipt. A Special Issue (SI) is not an issue of the journal. It is a collection of articles on a common topic. These articles are published in the regular issues of the journal when they are accepted (no delay) but additionally labelled with the Special Issue name (including a link). A single click on the link will organize all the articles on the Special Issue webpage.
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According to Web of Science data, the impact factor for Catalysts 2018 was 3.444. The five-year impact factor was 3.808. Catalysts now ranks in Q2 of the "Chemical, Physical" category.
According to Scopus data, the CiteScore for Catalysts 2018 was 3.85, which ranks it in Q1 of the “Chemistry, Physical and Theoretical Chemistry” category, and Q2 of the “Chemical Engineering, Catalysis” category.
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If you have helped review for MDPI journals and got a discount voucher, you can use it.
In order to plan for the whole paper project, I appreciate you could inform me within three weeks as to whether you would be willing to contribute. I also encourage you to send a short abstract to me (grzegorz.boczkaj@pg.edu.pl) or to Caroline Zhan (caroline.zhan@mdpi.com) in advance.
Sincerely hope this invitation will receive your favorable consideration.
Best regards,
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Department of Process Engineering and Chemical Technology, Faculty of
Chemistry, Gdansk University of Technology, 80-233 Gdansk, Poland
Caroline Zhan
Assistant Editor
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Thanks for your invitation. We can contribute if publication charges are waived.
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I do not have a laboratory fume hood to extract air, therefore I need to use the EMS only with a gas mask of "3M ™ Half Facepiece Reusable Respirator 6300/07026 (AAD)" in a Waterproof Protective Suit Safety Overall , gloves and protective glasses.
I am not sure if this gas mask is enough to avoid risking my health by breathing the released steam, even working outdoors.
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Ethyl methanesulfonate is a highly dangerous mutagenic and teratogenic organic compound with a melting point at around 25C, as you probably well know . No, you should not use it unless under a laboratory fume hood and GLP conditions, do not risk your health and professional character.
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Polyhalite is a multi-nutrient source, its application assume to be changes the soil biology and nutrients chemistry on long term basis
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The chemistry would help respondents
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Hey scientists,
I am just wondering what functional groups can be added to a hydrophobic molecule to make it water soluble at basic pH?
As a case study, let's just consider ethyl benzene as the scaffold. Not very soluble in water.
How can we make it soluble at basic pH? But extending functional groups to the carbon chain.
I know for instance, that you can have ethyl benzene. It can be made soluble at acidic pH by adding an ammonium chloride group. If you could convert ethyl benzene to phenethylamine by adding an amino group to the carbon chain then you got ethyl benzene. Still not very soluble. But if you react phenethylamine with HCl then you group phenethylamine-HCl or phenethylammonium chloride which is very water soluble at pH less than or equal to 7.
If you had ethyl benzene, what functional group could you add to make it soluble at basic pH?
I think that if ethyl benzene if we added a COOH group to the carbon chain we would have 3-Phenylpropanoic acid . If we reacted NaOH with that we would have 3-Phenylpropanoate Sodium Salt which I predict would be soluble at basic pH.
Is that correct? What other functional groups could I add to ethyl benzene's carbon chain to make the molecule water soluble at basic pH. Are there any functional groups that I could add to the carbon chain of ethylamine to make the molecule water soluble at basic pH and also positively charged? Like for example phenethylamine-HCl is positively charged but only soluble at acidic pH.
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Anything that would have a charge at basic pH, such as phosphate, sulfate, carboxylate, or tetrazole would help with solubility, but these are negative charges, of course. A quaternary ammonium group has a positive charge.
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In experimental, the bond energy per atom rises quadratically with the number of bonds then why in simulations this bond energy per atom rises linearly with the number of bonds per atoms?
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I will get back to you soon.
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dear friends, what is the most suitable iron complex to work with photo-Fenton without needing to stabilize the pH between 2.5 and 3?
I would like to work with the reaction at a pH between 4.5 and 6, would it be possible using some iron complex? like for example ferrioxalate?
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In the paper, "Heterogeneous photo–Fenton treatment for degradation of indigo carmine dye ". Cosme-Torres, et al., MRS Advances © 2019 Materials Research Society DOI: 10.1557/adv.2019.451 . 23 de febrero 2020. https://www.cambridge.org/core/terms,
you can read about this topics
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Could anyone suggest me some good papers which involves the coating or mixing of MXenes with conductive polymers such as PEDOT or PANI or any other conductive polymer for that matter.
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Dear Lokesh Murali, by in-situ polymerization, you can easily solve MXene and aniline in the same solutions, then mix them by ultrasonication, and next initiate polymerization with dropwise addition of APS. the following paper is the same approach for PANI and clay layers:
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How can I get involved in writing an article with someone else?
Does anyone want me to participate in writing a review article?
How?
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I agree with you Mr. Naimish Kumar Verma.
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Suppose you have a mixture mostly comprised of saturated fatty acids of carbon chain length C10-C20. Is there a process to convert them to unsaturated fatty acids?
The opposite process is well known. Margarine is produced via hydrogenation of unsaturated fatty acids to obtain saturated fatty acids. Is there something like a dehydrogenation process for saturated fatty acids?
If this process is feasible, could it be done in a targeted manner to yield mostly Omega-3 and Omega-6 fatty acids?
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If I dissolve 35 g of NaCl in 100 ml, what will be the approximate specific gravity?.
Is it 1.35? or is there some trick?
I read that saturated NaCl soltion has specific gravity of 1.2.
Also I read 35.9 g of NaCl can dissolve in 100 ml of water (which will approximately give 135.9 g/100 ml solution.
it means 1359 g/L, which means 1.359 specific gravity.
I am bit confused. (did I do a mistake?).
please help me.
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I. It is not clear from the enunciate if you are referring to volume of solvent (as it is often the case with solubility data) or to volume of solution (as it is typically the case for concentration given in volumetric basis).
II. I suggest that you check my posts elsewhere at this forum:
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Hi Research Gate,
A little background first: I'm a physicist, and I've done most of my work studying how chemical reactions move when they're pushed around by fluid flows. The trouble with this is I'm very limited because I don't know a lot of chemistry. I understand chemistry when I see it, but need to have a reaction identified before I can start trying to understand it. What this means is I have done most of my research on a single chemical reaction (The Belousov-Zhabotinsky reaction). The interesting phenomena around the BZ reaction, weren't my focus though, it just happened to be a reaction I knew how to make and that I could easily watch with a camera. However, I now want to go a little deeper into what's happening and the complex chemistry of BZ just gets in the way of understanding.
So I am asking you all if anyone has a suggestion for some interesting chemical reactions. For now I'm especially looking for reactions that 1) occur in the aqueous or liquid phase (so they can flow but are easy to contain) 2) Will sit inert until activated (now ideally I'd like the reaction to be completely mixed but need a catalyst to start an autocatalytic reaction, but I'd also take reactions where nothing happens until the second ingredient is added).
I'm also especially interested in reactions where it's easy to visually tell one state of reaction from another (say using an indicator dye). It would also be good if I could make the reaction from pretty standard chemistry supplies. Lastly I'd of course like reactions with practical import, say if the reaction makes something useful.
I know it's quite a list of things, but I'm hoping some helpful chemists (or even high school chemistry teachers really. As I said I'm not an expert on chemistry), are willing to pitch some suggestions.
If it's a reaction you study but don't want to deal with fluid dynamics on, great! I'm plenty willing to talk about what I'm trying to do.
~Thanks for reading, and hope you can help!
Thomas
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Well, if I were you, I wouldn't "mix a chemical reaction", just a reaction mixture. I wouldn't "move a chemical reaction" either. The chemical reaction also cannot be "pushed around by fluid flows" or "flow". Unfortunately, there are more awkward or incorrect phrases in your text. It is clear that you are a physicist and not a chemist.
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I am following this recipe for PBABr synthesis. I added HBr (48 wt % in H2O) to Methanol and PBA solution at 0 degrees celsius. But after 2 hours of stirring I am not able to see precipitates. I have to evaporate the solution at 50 degrees celsius to obtain precpitates, I did that and still did not see any precipitates. Please help me with this. Thanks in advance!
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Dear Jitesh Pandya, please check the attached file and the references therein. My Regards
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I have a 200 mg/ml ampiciline solution, how much should i add to 300 ml of LB medium to get the final concentration of 40 ug/ml?? How much bacteria (in ml) should i add to 75 ml of medium to dilute the culture 50 times??
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I agree with Professor Duried Alwazeer if you meant that the total volume is aliquot + 75 ml.
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Not another chemistry Nobel going to biologists!’ How many times have you heard that complaint? But is there really anything in it?
It’s sometimes said that the number of chemistry prizes awarded to work rooted in the life sciences – at least nine of the prizes since 2000 – simply shows how broad chemistry is: at the molecular scale, biology is chemistry. But does that argument stack up? A historian of chemistry and a mathematical chemist argue in a new paper that, not only have the chemistry Nobels indeed become more biological in recent decades but also the prizes of that nature tend to reward work outside of the chemical mainstream, being much more closely tied to research in the life sciences itself. In effect, they say, the chemistry Nobels are being shared out between genuinely different disciplines.
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Recall that the award goes to someone that made a discovery with significant impact. The MRI for medicine, Black Holes for Physics, past organic chemistry discoveries for Chemistry, etc their is now a bit more a blur between physiology/medicine and chemistry. In the past so much was still being discovered in chemistry but now discovery is being made but the award is not for just discovery but for knowledge and impact. So the lines blur for medicine and chemistry. We find discoveries in chemistry that impact medicine and have real world impact. So the cheap answer is that the lines are blurring and utility and impact are becoming felt in society thus making an argument for the justification.
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There are many research in field of "Transport in Porous Media" which is applicable from CO2 storage to chemistry engineering.
I like to collect more information on
What is going on right now in researching in this field?
And which areas in this field has remained untouched yet?
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Previous studies are mostly using default commercial codes for their modelling, perhaps developing your own code for a specific model could be useful for future studies.
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They've invited me to publish and to become a reviewer/editor.
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Elecia Henry International Journal of Pharmacy and Chemistry is not indexed in Scopus or Web of Science Master Journal List. Please make sure before submitting your paper that the journal is indexed at least one of them.
You can find the list of predatory journals here. https://predatoryjournals.com/publishers/
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I am looking for a fast publication Scopus index journal with more than 1 impact factor, in organic chemistry review paper?
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Although MDPI journals offer a fast publication process, they are highly expensive. So, the choice is totally up to you.
Regards
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I got a silicone substrate and I coat it with a conductive polymer.
But the conductive polymer doenst adhere very well, I did a crosscut test and the conductive polymer fully detached.
Which possibilities do I got to improve the adhesion?
Thank you.
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Try to use processing in HMDS (hexamethyldisilazane). For photoresists it work well.
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I've already checked solubility of sodium chloride (NaCl) in water(20℃).
According to the solubility data, 359 grams of sodium chloride should be dissolved in 1 L water.
so I put 245.2 grams of sodium chloride into 1 L water and let the mixture into the ultrasonic cleanser and shaking plate for minutes, but It doesn't dissolve well. I can even see that the powder is deposited.
I want to make a sodium chloride solution with a concentration of 245.3g/L.
Can you tell me what the problem is?
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Please note that sodium chloride solution with a concentration of 245.3g/L is not to be obtained by dissolving 245.2 grams of sodium chloride into 1 L water. Instaed 245.3g of NaCl should be dissolved in somewhat less water, in a volumetric 1L flask, after that filled up to 1.000 L of solution.
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Good research is based on good relationship between the mentor or supervisor and the scholar. What are the qualities a supervisor or mentor must have to have a healthy and friendly environment in the laboratory?
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1. Patience.
2. Knowledge of field and ability to impart that knowledge to others.
3. Ability to ask questions and define specific aims
4. Writing skills to produce grants and publications.
5. Research support in terms of grants or other types of research funding.
6. Contacts, perhaps a network of researchers with similar interests.
7. Foster attendance a scientific meetings, including presentations by students.
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I'm an intern in a big company which makes flexible polyurehane foam for the automotive sector and I'm working on sound absorption properties of PU foam. I'm not chemist so I'm trying to improve these properties only by modifying process parameters.
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Dear Alvin Kissoondoyal, if it has such a shielding effect it will help and contribute in sound isolation. The main effect is that of PU bulk structure. My Regards
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ANSYS or ABAQUS donot correlate materials chemistry wirh the observed or simulated mechanical properties. Is there a software that can do this structure to property correlation. ?
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Thank you all
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Hello,
I need to impregnate the pores of a MOF with cu(acac)2, which I will then reduce under vacuum to copper nanoparticles. I plan on using the incipient wetness approach to do so. However, my MOF will not be in a powder form, but rather a self supported, fibrous mat form ( ). According to my current research, the solid support catalyst (MOF) is typically stirred as the metal precursor solution in chloroform (or other solvent) is added to it, yielding a paste. However, I cannot stir my fibrous mat. Will simple immersion of my mat in the metal precursor solution be sufficient to impregnate the pores of the MOF with the precursor? Or would a drop-wise method of adding my solution work without stirring the MOF? Is there another way around this issue?
Thank you for any answers!
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I agree with the method suggested by Frank T. Edelmann . You can even have excess liquid/copper solution and, given enough impregnation time, the diffusion of copper acetate should fully impregnate the MOF. You can determine the actual metal loading by measuring the copper concentration of the liquid before and after impregnation and calculate the loading by material balance.
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I'm working on counter electrode for DSSC application, i would like to know if the CoSe can be doped with a MXene like Ti3C2Tx.
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Dear Lokesh Murali please see this useful article entitled MXene supported CoxAy (A = OH, P, Se) electrocatalysts for overall water splitting: unveiling the role of anions in intrinsic activity and stability
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I'm interested in reading about popular research being conducted in the organic chemistry world. Any ideas where to start?
May we design intelligent reactions or intelligent reactant?
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Hottest topics right now in organic chemistry research:
1)Synthesis of nano-materials involving metal catalyst to control COVID-19
2)Isolation of Biologically active compounds of plant products to control COVID-19
3)Develop recombinant DNA Technology to control COVID-19
4)Development of Green technology to produce COVID-19 vaccine
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Hi, everyone.
Our lab is going to use ISO 12966-2 and 12966-4 and there is one moment in sample preparation (rapid transmethylation method under alkali-catalysed conditions) that I can't understand. It is about the addition of saturated sodium chloride solution after transmethylation reaction. Maybe I'm not so good in chemistry to understand the purpose of this action. So, can anyone please help me to get it?
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In the same way of Moosa Faniband, when you add NaCl, to aqueous phase become more polar, changing the partition coefficient. So, the analyte will be push to organic phase, increasing concentration in isooctane.
Hope helps
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Is there a way to dope or combine the FeSe alloy onto a MXene (Ti3C2Tx) which can be used as a electrode for energy applications?
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ball milling (maybe coating) and some solution methods (simple composition) are the easiest way, but not novel.
Some in-situ synthesis method could be tried out, which should be well-designed.
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Considering the context of the COVID-19 pandemic that requires remote teaching activities. In the case of Chemical Education, which requires a high degree of abstraction and the use of visualizations can effectively contribute to the student's learning process, how does the teacher deal with the relationship of macro, micro and symbolic representations, in online teaching?
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I think that the teacher can use some applications that are online intended for learning the nomenclature, elaboration and spatial representation of molecules. There are also reaction simulators and laboratory practices where through color change you can explain and discuss with students the causes of a color change or a gas release. Also the teacher and students can make representations through animation programs that are useful to represent (model) some change or transformation of the matter.
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Is is possible to find out if a material can function as a cathode or anode by just looking at cyclic voltammetry.
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Hi Lokesh,
Can I ask more about your goals with this project? You can in principle get almost any conductive material to act as either a cathode or an anode based on the potential you apply to that material, so long as you have a counter electrode to facilitate the closure of the circuit. The question is how good of an anode or cathode your material is, and that will largely depend on what reaction you want to occur within that material or at its surface.
To give a concrete example - and sorry here if I am using a different sign convention (these things can be tricky, but I come from a U.S. Chemical Engineering background): if I apply a cathodic (negative/reductive) potential to a platinum electrode in a conductive aqueous solution, I'll drive a net cathodic/reductive reaction (such as hydrogen evolution). If I apply an anodic (positive/oxidative) potential to that same platinum electrode in that same aqueous solution, I'll drive a net anodic/oxidative reaction (such as oxygen evolution). And if I have two platinum electrodes in the system at the same time, then one can act as a counter to the other; one will drive hydrogen evolution, and the other, oxygen evolution. There is nothing different about the electrodes or the solutions they are in, except the fact that I am controlling the relative potentials of the electrodes through the input of energy into a potentiostat (or similar device). Note: this is an electrolytic example, but I'm happy to discuss things from a galvanic cell perspective if that is more useful.
Best wishes,
Kindle
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For our research subject in high school, we are required to conduct a research that can be done at the safety of our homes. Does anyone have any suggestions on what kind of topics we can research on? Thank you!
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When I was in high school I did an experiment on 3 different light colours (red, blue and green) and their respective effects on green bean plant growth. You can try this experiment using different light colours or different plants.
Or you can conduct a research on the effects on soil pH on plant growth.
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Dear Chromatographers,
This method was developed on LC MS/MS. The quantifier for both analyte and internal standard have same product ion, will that have an impact on overall analysis. Any supporting article to read more about this would be very helpful.
Thanks
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Hi,
For those having a cross-talk problem, it is better to choose the deuterium or carbon isotope dilution method for internal standard (IS) quantitation. If you cant provide the isotope synthesized molecule or co-elution exist and you cant improve the chromatographic resolution then I strongly suggest switching your IS with an analog molecule, which behaves like your target compound (Extraction yield, ionization suppression effects etc.) but also giving fragmentation product at different MW far away from your target fragments.
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As you know, a time crystal shows oscillations with a period longer than the driving force. Is it possible to use this feature in molecular machine synthesis? Does this provide any advantages to molecular machines?
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Hi
Can anyone help me how can I calculate adiabatic temperature in chemical reactions using software except HSC chemistry?
Thanks in advance
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What you need is the enthalpy of reaction, the average specific heat and the density of the reaction mixture. You seem to need a database of the physico-chemical properties of the ingredients more than a ΔTad calculating software.
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I saw in a lot of scientific article, in chemistry since I am a doctoral student in chemistry, the authors use software to draw their manipulations, I am willing to have some software to train me.
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For Chemical Structure and Graphic
For scientific modeling and graphic design you may use-
3. Adobe Illustrator: https://www.adobe.com/
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I got the idea from using filters and other filtration systems in previous research experiences, and also how recently... someone gave me a bunch of Monster Energy drinks but they aren't sugar free so it got me thinking how it would be possible to extract the sugar from the Energy Drinks mechanically.
Sugar molecules are 1nm in size
salt (NaCl) is .06nm in size and water molecules are .275nm in size.
Would this work as planned or is there something my reasoning has a huge gap in? :)
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Not possible it is in dissolved state. You need to use evaporative crystallizer
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Hello,
Cetyl alcohol is soluble in solvents like acetone and alcohols but not water. Cetyl alcohol is a waxy substance at room temp with a melting temp at around 50 dC.
If I want to dissolve cetyl alcohol in a solvent at room temp, will it dissolve? Or do I need to heat the mixture to CA melting temp?
Originally, I was thinking I would have to heat it. But then I thought there are substances that are solid at room temp but still have the ability to dissolve at room temp...
Thank you.
Kind regards,
Lara.
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Brilliant, thanks for confirming!
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I understand vaguely that the first author is supposed to be the one who "did the most work", but what counts as "work" in this comparison? Does "most" mean "more than all the other coauthors together" or just "more than any other coauthor"? What happens when the comparison is unclear? How often is "did the most work" the actual truth, versus a cover story for a more complex political decision?
I realize that the precise answer is different for every paper. I'm looking for general guidelines for how an outsider (like me) should interpret first authorship in your field. Pointers to guidelines from journals or professional societies would be especially helpful.
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Welcome Frank T. Edelmann
Another important attached concept is:
1. Principal Investigator (PI) usually after the name has ** PI
2. Co-Principal Investigator or Co-Investigator (Co-PI/Co-I)
3. Faculty Participant
Traditionally, the last author position is reserved for the supervisor or principal investigator. As such, this person receives much of the credit when the research goes well and the flak when things go wrong.
Multiple “first” authors. Additional “first” authors can be noted by an asterisk or other symbol accompanied by an explanatory note. This practice is common in interdisciplinary studies; however, as we shall explain further below, the first name listed on a paper will still enjoy more visibility than any other “first” author. https://wordvice.com/journal-article-author-order/
Multiple “last” authors. Similar to recognizing several first authors, multiple last authors can be recognized via typographical symbols and footnotes. This practice arose as some journals wanted to increase accountability by requiring senior lab members to review all data and interpretations produced in their labs.
For details please read attached PDFs
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I bought G4 PAMAM dendrimer from a company but they aggregated. The size of them changed from 5nm to 100nm and I cannot work with them because the NH2 functional groups of dendrimers are not available for a chemical reaction. Please guide me, how can I separate PAMAM dendrimers? Is there any pretreatment?
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Hi,
I totally agree with Pr. BOUAZIZ, you can use ultrasound for the deagglomeration of coarse particles.
With my best regards
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Hello researchers,
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What equation? Do you mean the Michaelis-Menten equation? They can be determined graphically on the basis of the V = f (cS) curve, or can be calculated using, for example, non-linear regression.
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Indeed, I have observed that there is some scientific journals that listed in Scopus sources of not good quality from scientific point of view. At the same time some Universities are depending on Scoups in a similar manner to that of Thomson & Routers or Clarivate analytics.
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LanguagesEnglishAccessProvidersElsevierCostSubscriptionCoverageDisciplinesLife sciences; social sciences; physical sciences; health sciencesTemporal coverage2004–presentGeospatial coverageWorldwideNo. of records69 millionLinks
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I am writing my thesis about metabolomics, and after reading about metabolites and proteins and how these have been measured through time for characterization and kinetics, I think metabolomics could be the one analytical technique that enables universal measurement of all intracellular, and possibly extracellular molecules. Even proteins with intact protein mode, for example. Maybe I'm too naive and inexperienced, and saving for some differences to enable separation (column chemistry), and ionization (ESI v APCI v direct injection), what are your thoughts on this statement?
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Hi Luis, metabolomics studies the metabolome in a top-down, experimental manner. The metabolome comprehends the whole ensemble of small molecules, with grey limits within biological oligomers. Proteins, genes, transcripts, are not part of the metabolome, neither lipids or glycans in my opinion. While MS or NMR can/will 'virtually' be able to obtain information about any molecule, for sure it will not be in a high-throughput manner, measuring everything at the same time. In fact, metabolomics is the least high-throughput omic technique where robust bioinformatic pipelines are still under development when compared to proteomics, genomics, etc. Many analytical techniques are 'the true' technique to answer the problem to which the technique is focused to retrieve data valuable to be evaluated.
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As a requirment in my project, I have to synthesize Formamidinium bromide (FABr). According to the protocols which are mentioned in the articles, I've synthesized this material but I think there is an error in my work?
Does anyone has the experience of this synthesis?
Because in the articles, the authors don't express all the steps, I want to know if there is any critical strategy during the synthesis of FABr and specially in the purification stage of this process.
I would appreciate if you point out a reliable article which has mentioned all the stages of this synthesis with it's details.
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Dear Reads Nima Tabatabaei Rezaei,
Have you tried the way I propose to go ahead for the same? Just try it.Somebody has done and successfully got some very interesting synthesis results.
Because of the good thermal stability and superior carrier transport characteristics of formamidinium lead trihalide perovskite HC(NH2)2PbX3 (FAPbX3) has been considered to be a better optoelectronic material than conventional CH3NH3PbX3 (MAPbX3). The FAPbBr3 photodetector’s responsivity to two-photon absorption with an 800-nm excitation source can reach 0.07 A W−1, which is four orders of magnitude higher than that of its MAPbBr3 counterparts. Materials such as Formamidine acetate, lead bromide (PbBr2, > 98%) and hydrobromic acid (48 wt% in water), Gamma-butyrolactone (GBL) and N,N-dimethylformamide (DMF) may required for synthesis.
Formamidinium iodide (FAI) and formamidinium bromide (FABr) can be synthesised by dissolving formamidinium acetate powder in a 2x molar excess of 57%w/w hydroiodic acid (for FAI) or 48%w/w hydrobromic acid (for FABr). FABr can be synthesized by slowly dropping 10 mL hydrobromic acid into 50 mmol (5.205 g) formamidine acetate in a flask, accompanied by continuous stirring at 0 °C for 2 h under argon atmosphere. The product FABr was formed once the solvent was removed using a rotary evaporator at 70 °C. The crude white powder was dissolved in ethanol and subsequently reprecipitated in diethyl ether. Then, the filtered product was dried at 60 °C in a vacuum oven for 24 h for further use.
Ashish
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How do you obtain particle size distribution from SEM?
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“Automatic” determination of particle size distribution
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Does anyone know of, or use, commercially produced surfaces for contact measurements (control material)? As an example, is there a producer of PTFE discs with highly controlled surface roughness and chemistry that I can purchase? I have not found any....
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Dear Michael Pujari-Palmer, why don't you use directly AFM for contact measurement? My Regards
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Several studies on combustion of bio diesel/petroleum fuel blends in IC engines and other power generation / combustion devices discussed extensively about the influence of fuel unsaturation on NOx emissions. A fundamental question arises on how we quantify fuel unsaturation?
I would like to start a discussion on the topic - How to quantify fuel unsaturation ? what would be an appropriate index to quantify unsaturation irrespective of the family of origin of fuels - like methyl esters, ether, alcohol , alkanes, alkenes, alkynes or aromatics or a weighted combination of aforementioned categories.
Our research group's take on this -
We have established a parameter - Degree of unsaturation that serves as a common platform across different fuel families (esters/alkanes/aromatics) to quantify the effects of fuel unsaturation, particularly with petroleum/bio-diesel blends. DOU can be evaluated based on the average molecular formula of the fuel alone without involving complex and expensive experimental procedures such as those involved in the measurement of iodine number and bromine number.
If interested, please follow the link to access the research work we have conducted at our laboratory to investigate the effect of fuel unsaturation on nitric oxide emissions.
Message me to get a copy of this article.
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Dear Ana
If you intend to determine all double bonds (including aromatic, carbonyl and etc) I recommend using the NMR analysis, although you will need a specific lab, this equipment is usual in chemical departments.
Some articles may help you with this problem.
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I am wondering why some stains do not work by themselves and absolutely need to be paired with a counterstain to work. What is the chemistry behind this process? Is there a nice book that explains this process in depth?
Thank you very much for your answer in advance.
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Hi Alida, this is a really good question. I think that the basis for this is the combination of basic and acidic dyes to stain acidic/basophilic, and basic/acidophilic molecules in tissue, respectively. I realize that your question is really asking why some stains won't work without their counterpart. I know that you must use basic dyes before acidic dyes, and alcohol before aqueous, otherwise staining will not work. I suggest Animal tissue techniques (A Series of books in biology) 3rd ed. by Gretchen L Humason. It was published in 1972, but is still one of the best histology books I've ever seen. You can get it on amazon for about $10, ISBN-10: 9780716706922 .
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I come across many reactions like A + B --> products.
How to consider "products" as a species and solve the kinetics in simulation/modelling, as such the reaction is unbalanced by logic of chemistry.
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That is the weakness of lumping: The mass balance of components requires information on the product composition, which is not accessible after lumping. One might use average values for the products, such as molar mass or density. Those average values, however, depend on the composition, which is not known after lumping. The mass balance consequently contains errors. Therefore it is probably more meaningful to go for molar balances assuming constant density or flow rate (note that appropriate assumptions depend on the specific problem).
In general the applicability of lumping always depends on the accuracy required, which is defined in the problem statement. Therefore it has to be clear, which kind of assumptions are appropriate (e.g. constant density, flow rate, etc.). Furthermore, none of the products should affect the kinetics of the involved reactions.
Please also keep in mind that your question is rather generic and can't be answered in general, as the answer always depends on the specific problem.
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Hello everyone,
I do calculations on compounds with about 25-30 atoms (hydrogen, carbon, oxygen) and about 110 electrons in a water solvent (SMD solvation model). These are optimizations and frequency calculations. I'm searching for the best reference method I could compare results with. These systems are being calculated with B3LYP/6-311**G(d,p), B3LYP/aug-cc-pVDZ and B3LYP/aug-cc-pVTZ.
I was thinking about CIS/6-311++G(d,p) but have found it's not the best pick - it's barely accurate when calculating frequencies. So I came up with an idea to recruit CCSD/cc-pVTZ, though three things are running through my head:
  1. I don't want calculations to run for more than 1 week (I do use 4 processors and 40GB; can try to increase it slightly)
  2. Because of the number of hydrogen bonding I find diffusion function necessary, though adding them to the reference method may demand much more time and computational resources in order to be calculated. How to bypass this problem?
  3. Maybe just use CCD/aug-cc-pVTZ? However, how long will it be calculating?
  4. Or just use optimized geometry from B3LYP/aug-cc-pVTZ level as a starting one, and then perform CCSD(T)/aug-cc-pVTZ with frequency and optimization calculations.
The main problem arises from the technical features of the computer I'm using and time. What's is your opinion? Maybe use something completely different?
Thank you.
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If you were using Gaussian09, you might wanna try b97d3 or wb97xd functional which includes a better dispersion correction.
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Morpholine acetate is one of the ionic liquids I need to know about, but I couldn't find it. Is there anybody who can help me?
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Try Zinc15 or VulcanChem (https://www.vulcanchem.com/) Or a vendor listed on PubChem. They are usually more responsive than others found on the Internet.
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Dear Scholars
I was wondering if anyone can recommend a publication on crude oil chemistry - particularly on SARA (Saturates, Aromatics, Resins, and Asphaltenes) classifications.
Thanks.
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I am working for PEM fuel cell cathode material. I am confused regarding the onset potential determination for my catalyst (CV attached, fig 1 is complete CV while fig 2 is its zoom image for clear understanding of change in reduction curve direction) and also why the reduction starts from 0.8e-4 A instead of 0 A. I performed this CV in calomel electrode under oxygen in 0.5M H2SO4.
i) If I use Argon and overlap both the graphs then probably the curves start to separate at around 0.58V.
ii) I have read in some discussions to consider the onset potential at which current density approaches 0.1mA/cm2 while in other discussion, I have read to consider 20microA/cm2 as onset potential. If I plot LSV curve for current density (instead of current) vs potential , then in first case (0.1mA/cm2), it would be 0.785V while in second case (20microA/cm2), it would be 0.775V
iii) If I only consider the point from where curve starts to change the direction of reduction peak, it would be o.64V or 0.56V
iv) if I draw tangents then this would be around 0.5V.
So please help me in i) analyzing onset potential ii) guide me why there is positive current in the reduction peak iii) i also don't know what does the background correction mean and should I need to do it for my CV? All potentials are measured in SCE.
So please help me to analyse onset potential in the best way and also guide me why there is positive current in the reduction peak. All potentials are measured in SCE.
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@Muhammad Shoaib thanks for asking this question. The answers here my mind to a greater extent.thanks
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In our field of research (chemistry), successful PhD research often requires a lot of experimental work in the laboratory. The completion of a PhD usually takes between 3 and 5 years. What's the duration of a PhD in your area?
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It depends on the topic and process of the university and the cooperation of supervisors as well.
Approximately 3-4.
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So I have some pH = {4, 7, 10} standard buffer solutions from Fisher Scientific. But they must have went bad or I must have contaminated them because when I try to calibrate my pH meter to 4 using the pH 4 standard buffer solution, it calibrates the pH meter to 2 which obviously isn't right because it should be 4 so I can't trust the standard buffer solutions!!!
I need to do some experiments which require that I accurately calibrate the pH meter which means I can't titrate the standard buffers with HCl or NaOH. I have to know the exact quantities. Might seem a little over-the-top, but I want to be really certain about the math.
I intend to prepare my own calibration standards using exact quantities of chemicals. Total concentration should be 0.1 M, volume needs to be 100 mL. I think 0.1 M is a good choice because that should have low ionic strength and not much crazy debye-huckel variations in pH.
I am pretty certain that I know how to prepare a pH = 4 standard buffer solution using acetic acid and sodium acetate. But I am not quite sure how to prepare a pH 7 standard.
First of all, is this exactly how I should prepare a 0.1 M acetate buffer in 100 mL?
According to pubchem the pKa of acetic acid is 4.76. I have a chem textbook which tells me that the pKa is 4.74. Not much difference so I will assume pubchem is right.
HA + H2O --> A- + H3O+
Acetic Acid + H2O --> Acetate + H3O+
Henderson-Hasselbalch Equation: pH = pKa + log([A-] / [HA])
pH = pKa + log([Acetate] / [Acetic Acid])
= 4.76 + log([Acetate] / [Acetic Acid])
For the total concentration:
[Acetic Acid] + [Acetate] = 0.1 M
The simultaneous solution to these equations is about:
[Acetic Acid] = 0.0852 M
[Acetate] = 0.0148 M
pH = 4.76 + log(0.0148 / 0.0852) = 3.9998 etc ... Pretty much exactly 4!
I have glacial acetic acid and sodium acetate.
Glacial Acetic acid is a pure liquid so its concentration is its density / (Formula Weight)
[Glacial Acetic Acid] = [(1.05 g/mL) / (60.05 g/mole)] * (1000 mL / 1 L) = 17.5 M
Basic Dilution Equation:
Initial Volume = (0.0852 M / 17.5 M) * 100 mL = 0.487 mL glacial acetic acid in 100 mL total volume.
Sodium Acetate --> Na+ (aq) + Acetate- (aq)
grams sodium acetate = (0.0148 moles sodium acetate / L) * (82.03 grams sodium acetate / 1 mole sodium acetate) * (1L / 1000 mL) * 100 mL = 0.121 grams sodium acetate
So I can exactly prepare a pH = 4 is 0.1 M acetate solution by adding 487 microliters of glacial acetic acid & 0.121 grams sodium acetate to 100 mL volumetric flask, and bring the volume up to 100 mL with ultrapure deionized water? Swirl to mix.
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I am confused about how to prepare an exactly pH = 7 phosphate buffer solution.
I know the step wise dissociation of Phosphoric Acid. But the problem is that I am not certain about the second dissociation constant.
H3PO4 --> H2PO4- (aq) + H+ (aq)
H2PO4- (aq) --> HPO42- (aq) + H+ (aq)
If I know the second dissociation constant of phosphoric acid I could figure out exactly how to make a pH = 7 standard 0.1 M phosphate buffer solution using phosphate salts.
My undergrad general chem text book is telling me the second Ka is 6.2 * 10^(-8) or the pKa is 7.208 and pubchem is telling me the second the second pKa is 7.09.
Thus I could use the Henderson-Hasselbalch Equation again with the total concentration to figure out the exact quantities. But I am not certain about what the second pKa of phosphoric acid is! Are undergrad chem textbooks just wrong? That's too much of a margin of error.
pH = pKa + log[(K2HPO4) / (KH2PO4)]
Also I was wondering if a 0.1 M solution of NaCl would have a pH of EXACTLY 7? Would it be more or less accurate than making the phosphate buffer?
NaCl is formed by the titration of a strong acid HCl with a strong base NaOH. Therefore the equivalence point of the titration of a strong acid and strong base should yield a pH 7 of neutrality forming NaCl.
So if I dissolved NaCl in water to yield a 0.1 M concentration would the pH be just as good as making that phosphate buffer solution?
I also need to figure out how to make a pH = 10 standard buffer solution.
Any advice? Can you make my life easier?
Thanks so much!
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There must be some problem with the pH meter then.. U should show it to a technician so that it can be fixed.
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We are planning to extract phosphorus from biochar by organic acids. If anyone has some procedure (concentration of organic acids & steps) please inform.
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@ Chandra, please have a look of the attached file.
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#COVID-19
Coronavirus Covid-19: Current Research. Open Access Publications Chemistry in Coronavirus Research: A Free to Read Collection from the American Chemical Society
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Can have a look - on the attached manuscripts
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I have extracted Manganese dioxide from zinc-carbon battery in order to prepare Manganese fertilizer . but it never dissolve , Why ??
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Please check the following link, I hope this can help:
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A biosafety level is the level of the biocontainment precautions required to isolate dangerous biological agents in an enclosed facility. The levels of containment range from the lowest biosafety level 1 to the highest at level 4. In the United States, the Centers for Disease Control and Prevention (CDC) have specified these levels. In the European Union, the same biosafety levels are defined in a directive. Sabanci University is following the same directive in accordance with Turkish biological safety regulation.
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I've made a synthesis in French a few months ago. Hope it will help.
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I recently read:
"The perovskite solution for the solvent quenching method (MAPI) recipe was prepared by dissolving 553.2 mg PbI2 and and 181.23 mg MAI in 1 ml anhydrous DMF/DMSO (4:1, v:v) to obtain a 1:0.95 molar ratio solution (PbI2:MAI) with a concentration of 42.96 wt %."
How can one get 553.2 mg of PbI2 and 181.23 of MAI (CH3NH3I) to be dissolved in 1 ml solution to obtain a 1:0.95 molar ration solution when the molar mass for PbI2 and MAI are 461.01 g/mol and 158.97 g/mol respectively.
I am confused. Thanks for the help in advance.
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I highly agree with the opinion reported by Frank T. Edelmann
Regards
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Some studies reveal that SARS-CoV-2 virus activity can be mitigated at the alkaline pH medium (above pH= 7.5). Any explanation about the mechanism or the Chemistry behind this phenomenon.
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The virus uses several protease enzymes, they are particularity sensitive to pH changes .
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Cheers Everyone.
I was seeing some uses of ionic exchange to recover NH4 by ionic exchange with other cations in a specific matrix. And it brought me to question what drives an ionic exchange to be better towards an ion in solution and not so good to another?
I thought maybe the charge of the cation would influence but maybe is not so relevant as here K and Ca are ahead of Na and Mg. Maybe the hydration radius as an important role in it instead? And can pH of the solution where ionic exchange is done affect also the selectivity of the ionic exchange knowing it can affect the lattice charge of the matrix?
Is there a way we can estimate this? or just by trial?
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Mostly pH is affected.
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I need to download a chemistry book the original version in English and translated into Arabic that can help me , it is very importante
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Dear crystallographers I have synthesized and crystallized a compound but after the XRD study i found out that the crystal structure of this compound already exists (the attached file A is my structure B is that of literature) but i noticed some differences :
- My structure's volume is large by around 7.6 A - some minor difference in cell parameters. - Clear difference in R1 (mine is better). - Difference in number of asymmetric units Z'.
My questions are: - Is my structure considered as a new structure ? - Can i publish it ? i have another structure (3rd one ) of the same compound but with a solvent inside the cell - Can i publish both structures (A and the 3rd structure ) in same article as new polymorphs ? ps: attached files: projection along the C axis of both structures with parameters Thank you in advance
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Dear Oussama,
From this picture I cannot state with certainty if it is the same structure (= the same molecule with the same crystal packing) or not, because the representation is different. The coordinates of the atoms are chosen differently with respect to the origin in A and B. You can probably shift your atoms in the unit cell so that the two structures look more similar.
From the unit cell it seems the same structure: the difference in volume is "negligible" and the different reported Z, Z' is likely due to a different definition of the moiety formula or sum formula.
But, in principle, the unit cell is not enough to decide if it's the same structure. As suggested, you can compare the simulated powder patterns. I also suggest to carefully compare the crystal packing by analyzing the intermolecular contacts and examining a bigger packing range (like for example 2x2x2 unit cells). Some programs also allow to overlay two crystal structures, to visually compare them.
In any case, you can most probably publish your structure along with the solvated form, with more focus on this latter, as it is new. Compare if there are real differences with the literature structure, for example, were they measured at the same temperature? Any conformational differences? I suggest you adopt the same atom labelling names and the most similar setting to the published structure, in order to facilitate the comparison both for you and for the readers.
Best wishes,
Arianna
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In the age of Covid19, is there a basic conflict between science and superstition in the discipline of medical knowledge? Are there some simple, sensible, robust and reasonable ways to distinguish a scientific statement (or fact) from a superstitious statement?
To stay focused, the topic will concentrate on science versus superstition in the scientific discipline of medicine. We will try our very best to stay focused and not stray off track. it is very easy to wander off message and be all over the map. i will try to summarize the key conclusions from time to time.
In the age of the Corona Virus, there are so many statements out there. The statements may not be scientific. But if they are not scientific, are they false? Are they fake? Are they simply statements based on superstition.
What should we do if people believe in statements that are not based on science? Should we be polite and tolerate their beliefs?
As long as people do not harm others, then from society’s point of view, the fact that people hold non-scientific hypotheses is probably benign. However, the trouble starts when the same people act these beliefs, and then cause harm to others. The question arises: what should society do in this case?
Based on the discussion, there are two assumptions and four categories.
Assumption1: Beliefs cannot be justified or unjustified.
Assumption2: hypotheses can be disproven
Scientific hypotheses that are based on justified facts in natural causation. Or scientific hypotheses have not been disproven (I prefer the negative formulation because we may never be able to prove anything but we are unable to disprove it.)
Since science cannot give a definitive answer, there are many competing answers that merit our attention, and we may not be able to select among them.
Non-scientific hypotheses are unjustified facts that may be “proven” in the future with better evidence and facts.
Pseudo-scientific hypotheses: not sure where these fit in?
Superstitions are unjustified beliefs in supernatural causation.
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Joseph Tham, thanks for a thought provoking question. I think we should tolerate and respect beliefs and ideas that are not considered scientific. Our intolerance of such beliefs and ideas could be the result of a lack of understanding of the science behind them. We should therefore subject them to rigorous testing using the scientific method. A practical example is the fact that the World Health Organization has not dismissed out of hand the herbal remedy from Madagascar that is claimed to prevent illness from COVID-19. Instead the remedy is going to be tested using established scientific principles. The null hypothesis can then be rejected or accepted. This is how Indigenous Knowledge Systems contribute to scientific advancement.
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chemistry is one of an interesting science in the world. but in most developing country student is nit prefer to learn chemistry. i mention the most two cases: in developing country mostly no laboratory accumulation, and there is no reference materials and so on.
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Sometimes it is just but a misconception and a result of peer pressure. Such students require alot of motivation for a positive attitude to the subject.
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When a piece of copper foil is placed in a test tube of iron(III) chloride solution? Fe goes from Fe3+ to Fe2+ and Cu2+ goes to Cu. Both are being reduced?
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Dear
Bram Kuijer
, in such redox reactions, it is not possible that all reagents are being reduced. Oxidation and reduction must always take place simultaneously. In this case., the metallic copper is oxidized by iron(III) chloride, i.e. FeCl3 is the oxidizing agent which is itself being reduced to Fe2+. On the other hand, you start with metallic copper (Cu0), which is the reducing agent. During the reaction, Cu0 is oxidized to Cu2+, i.e. the copper foil slowly dissolves.
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Any thoughts and recommendations on good articles, textbooks and resources on the topic of permanent magnet materials (e.g. neodymium) in terms of phenomena associated with their ageing and degradation under temperature, chemical, mechanical and electrical/electromagnetic stressing.
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Herbst, J. F., and J. J. Croat. "Neodymium-iron-boron permanent magnets." Journal of magnetism and magnetic materials 100, no. 1-3 (1991): 57-78.
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Hello everybody
I want to simulate MXene by means of molecular dynamics method. But it seems that I need the Mxene atomic structure as a file in .cif, .pdb, or .mol format.
Is it possible for anyone to tell me how I can get the files or how I can build the atomic structure of MXene?
Thank you so much
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Hi Saeed,
If you have the top view and side view of the MXene, with dimensions present on the figure, you can make the system. The top view and side view of relaxed MXene systems should be available online.
Also, if you have the atomic coordinates for a unit cell, you can use the lattice vectors to make large supercells.
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Biological techniques are methods or procedures that are used to study living things. They include experimental and computational methods, approaches, protocols and tools for biological research.
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At both very high and very low water activities, lipid oxidation rates are high compared to the rate at intermediate water activities. What can explain this trend?
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The relationship between rates of lipid oxidation and moisture is complex. The amount of water, the water activity and the state of water in a food, along with other factors, must all be considered.
For most fresh or tissue foods that have moisture contents between 60 - 95% have a water activity very close to 1.T he mode of deterioration at this water activity is generally microbial or enzymatic in nature. Direct lipid oxidation (i.e. not enzyme-mediated) is not an important source of deterioration at this high water activity since other modes of degradation will deteriorate the food first.
Concentration, freezing, and drying are mechanisms by which the water activity of food can be reduced. Such processes may bring the food into the intermediate moisture or low-moisture region where direct lipid oxidation becomes a more important mode of degradation. Also, during dehydration, free radicals can be formed which accelerates lipid oxidation. Freezing can also lead to the acceleration of lipid oxidation rates through the concentration of substrates and catalysts in the unfrozen portion of the system.
On the other hand, Chou et al. (1973) found that water activity primarily affects matrix swelling and thus substrate/reaction site availability as well as catalyst mobility.
Hereinbelow the tow common theories related to the relationship between water activity/content and lipid oxidation are briefly discussed:
Monolayer theory
Unlike most aqueous chemical reactions, the rate of lipid oxidation that takes place in the oil phase is observed to increase as water activity is decreased below the monolayer (i.e. water molecules that are bound tightly to the food surface). This can be explained by considering the role of water in this reaction. It has been suggested that the monolayer of water—or rather, the water saturation of polar groups in lipids—is necessary to cover the surface of the lipid, preventing it from direct exposure to air. This monolayer is essentially “bound” water with limited mobility and is assumed to not participate in chemical reactions. Several studies have found that a variety of foods are most stable to lipid oxidation at a relative humidity or aw consistent with the monolayer.
On the other hand, water can form a hydration sphere around metal catalysts such as Cu, Fe, Co, and Cd. In the dry state, the metal catalysts are most active. As water activity increases, the metals may hydrate which may reduce their catalytic action thus slowing the rate of lipid oxidation.
This monolayer theory, however, cannot be applied universally.
Glass transition theory
According to the glass transition theory, one important function of water is its ability to act as a plasticizing agent. The plasticization of a matrix involves swelling of the polymer matrix when moisture is increased. The resulting increase in free volume might allow for faster diffusion of substrates in the aqueous phase which may lead to faster reaction rates. Plasticization may also increase the contact of the absorbed aqueous phase with the lipid phase. The number of catalytic sites increases such that the rate of lipid oxidation increases.
The above discussion shows that water plays both protective and prooxidative roles in lipid oxidation. In some foods at low aw near the monolayer moisture content, water is protective, presumably because it provides a barrier between the lipid and oxygen.
While the classic food stability map proposed by Labuza et al. (1972) shows lipid oxidation having a U-shaped relationship to aw, no U-shape was also observed; lipid oxidation actually slowed as aw increased as the case of freeze-dried food.
Overall, monolayer and glass transition concepts might not effectively predict lipid oxidation reactions in some foods if oxidation is primarily occurring in the lipid phase and thus would not be significantly impacted by water and the physical state of proteins and carbohydrates. On the other hand, water can play a major role in lipid oxidation chemistry if reactions are primarily promoted by water-soluble prooxidants such as metals. Unfortunately, the causes of lipid oxidation in low-moisture foods are poorly understood, which could be why measurements of water activity, monolayers, and glass transitions do not consistently predict lipid oxidation kinetics.
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Many efforts are spent to prevent, treat and stop COVID-19 spread.
but I think these efforts are fragmentary and not organized.
there is no platform for a scientific collaboration that could shorten the time of interesting findings, some nations hide some facts are a privilege of authorship or for other political reasons.
I think that all countries should a global platform for scientific collaboration.
Personally I have some ideas that could be proposed for the treatment of COVID-19 based on scientific facts but with the innovative mode of application, how and where can I try to apply them?
All nations should avoid wasting their time to find a solution for COVID-19 without international collaboration.
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Thats a very good idea to unite and make joint efforts to defeat the pandemic the world is suffering.
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How to deal with this problem?
Example I have 10 sample, and I use duplo method. And we have a target for our sample's CV is under 5%
In the 7th sample, the coefficient of variance is more than 5%, but it happened only in the 7th sample. In this case, another sample is fine (CV less than 3%).
Do you have any idea what is going on?
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Flow measurement can be performed with different methods. Accuracy of reading may depend on different factors like samples water etc.
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The SARS-CoV-2 genome was rapidly sequenced by Chinese researchers. It is an RNA molecule of about 30,000 bases containing 15 genes, including the S gene which codes for a protein located on the surface of the viral envelope (for comparison, our genome is in the form of a double helix of DNA about 3 billion bases in size and contains about 30,000 genes).
Comparative genomic analyses have shown that SARS-CoV-2 belongs to the group of Betacoronaviruses and that it is very close to SARS-CoV, responsible for an epidemic of acute pneumonia which appeared in November 2002 in the Chinese province of Guangdong and then spread to 29 countries in 2003.
A total of 8,098 cases were recorded, including 774 deaths. It is known that bats of the genus Rhinolophus (potentially several cave species) were the reservoir of this virus and that a small carnivore, the palm civet (Paguma larvata), may have served as an intermediate host between bats and the first human cases.
Since then, many Betacoronaviruses have been discovered, mainly in bats, but also in humans. For example, RaTG13, isolated from a bat of the species Rhinolophus affinis collected in China's Yunan Province, has recently been described as very similar to SARS-CoV-2, with genome sequences identical to 96 percent.
These results indicate that bats, and in particular species of the genus Rhinolophus, constitute the reservoir of the SARS-CoV and SARS-CoV-2 viruses.
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The Sarbecoviruses (SARS and SARS-related beta coronaviruses) are a faily diverse clade of coronaviruses. Merbecoviruses (MERS and MERS-related beta coronaviruses) are another clade with similar diversity. The SARS-CoV-1 and SARS-CoV-2 sarbecoviruses are quite distant from each other.
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Hello,
So I have conducted an experiment looking at the size of silica nanoparticles. However, the results I obtained showed that at a lower mass concentration of SiO2, the volume and radius of individual particles are greater than that of higher SiO2 mass concentration.
I can't seem to find an explanation regarding this and was thinking that at lower mass concentration the individual particles colliding somehow caused them to agglomerate together causing the bigger particle size.
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It may be due to aggregation, use stabilizing agents to reduce aggregation.
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kindly give the software details and download link
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MestReNova , ChemDraw professional for synthesis
Gold, Moe, Glide for computetional docking
Pymole
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Dear researchers,
I have some salt solution analysis.
I want to know is there any software to estimate the scale deposition thickness in a specific time period on a metal plate at a known temperature (like a stainless steel heat exchanger)
I want to predict the scaling thickness in evaporative and non-evaporative condition.
Thanks.
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I see some very good answers - we do the estimation by measuring the change in thermal conductivity of the space. The measurement can be more meaningful if you know the composition of the mineral deposit. The thermal conductivity of common water system scales is known. If the accumulation is, in fact, deposited, not grown in place - then the thermal conductivity model would be more relevant within repeated accumulation/settling of solids in that location.
Thermal conductivity is an accurate means of measuring the relative thickness but the results are more material with repeated measures or an accurate knowledge of the physical and chemical composition of the matter of interest.
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Seems like a silly question but I'm having trouble with searching for CIF files via https://www.ccdc.cam.ac.uk. I've used it before but I was on university campus so I think I was able to use more than just the simple search function. I think I used structure search before and I was able to type in the compound name and the structural formula to get a CIF file, but now as I'm working from home, I don't have a CCDC licence and so I'm restricted to just the simple search. I've tried just typing in the compound name and no results come up. Will I need to search compound names with a paper that potentially has a CIF referenced? Or have I just misremembered how to use CCDC! Any and all help appreciated, thanks!
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Hi Annie, you can try to search the CIF file you need at COD (crystallographic open database - http://www.crystallography.net/cod/) or Materials Project ( https://materialsproject.org/) database. They are free of charge.
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Column chromatography with Silica Gel columns with inbuilt UV detector.
Compound structure is mainly poly unsaturated fatty acids and analogs without UV handles.
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You have answered your own question. Proper chromatography methods require detection methods which are applicable to the samples under analysis. You may want to review the types of instruments, detectors, columns and materials available at your school before deciding on a final approach. Have someone in the school's analytical instrument lab assist you.
For HPLC samples with weak or no chromaphore, you will need to use a detector that does not rely on wavelength based light absorbance such as an RID, ELSD, CAD or MS, to name a few. Put a little time into researching this basic question so you will better understand the uses and limitations of these methods and detectors. I often suggest my students start with a keyword search on the web (GOOGLE or BING) to find examples and articles to review. This is one of the best ways to learn. Once you have familiarized yourself with the basics, be sure to ask your teacher for help in setting up and running some example methods.
BTW: You may also be able to derivatize some of your samples and use GC/FID or GC/MSD as an alternative to HPLC (only if the samples are appropriate).
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Assume a solution with acidic pH, which consists of 2 and 3 valent iron ions. With increasing the pH, iron content will precipitate.
Do ferric and ferrous precipitate in an equal pH? If no, at what pH will precipitation happen for these ions?
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I read that after leaching of oxidized zinc concentrates with sulfuric acid, the resulting solution is purified from harmful impurities like iron, copper, cobalt, nickel. And with a weakly acidic medium, pH = 5.2–5.3 iron ions are practically precipitated by the formation of hydroxides.
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Hello,
I am looking an all solid state halogenide ion conductor (conducting halogenides, not necessarily based on them) especially iodide ions for a solid state battery.
Poorly the research seems almost exclusively on monovalent cations like Na+/K+/Li+.
Also the ion conductor should have approximately 10^3- 10^-2 S/Cm at room temperature.
any ideas?
thanks a lot
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basically scholar is having maths and statistics background but he is doing research in fluid mechanics. he is interested but difficulty is finding problem and doing paper publications.
so we need some suggestions. how to develop knowledge on this research area being a mathematics scholar.
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If a person is good in mathematics and has command over it, that means he has good logic aptitude and grasping ability. If now he want to do research in Fluid mechanics of course he can. He should start with reading the basic physics books and gradually increase the level to engineering fluid mechanics. Which, at this stage, should be a matter of not more than 6 focused months. after that he will be able to do like masters. Do not run behind paper publication from the start it will a by product of your focused learning and problem solving.
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Hi everybody!
I am PhD in analytical chemistry and I make part of a multidisciplinary team working on the development of a web based solution focusing mainly on treatment and management of environmental chemistry data. But in order be more acertive in this project I need to interview researchers worldwide to trace a more realistic picture on how they deal with their environmental data.
Could any of you please help me by giving me a 40 minute interview? We could make it via WhatsApp or Hangouts (or other choice).
Messages in private to more details are welcome!
Thank you all very much in advance.
Yours sincerely
Gilson
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Dear Dr Gilson
I am ready to help if I could and be grateful to do something due to make progress!
I think many valuable media and journals could be useful for you such as:
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My lab has hydrazine sulphate. I need to convert it to hydrazine hydrate. How can I do this?
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Hydazine hydrate solution in water is basic (pH=11) but the solution of Hydrazinesulfate in water is acidic (pH = 3). So to get the hydrazine hydrate from hydrazine sulfate , the pH of the hydrazine sulfate solution has to be tuned to pH= 11.
Here the procedure:
Dissolve the Hydrazinesulfate in water ( 1 g in 30 ml), check the pH (then add Ambersep 900 hydroxide from resin (or any other OH from resins) and adjust its pH to 11. Filter the solution to obtain Hydrazine hydrate.
I have used this procedure recently, it works very well.
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I want built a small biochemistry lab for research purpose ( Phytochemical Study).
Phytochemical screening
 It refers to the extraction, screening and identification of the medicinally active substances found in plants. Some of the bioactive substances that can be derived from plants are flavonoids, alkaloids, carotenoids, tannin, antioxidants and phenolic compounds.
Please give me some guideline and references for built a small laboratory.
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Hi,
as
Sebastian Schmitt
mentioned, it is indeed necessary to provide a more specific question in this case. Depending on the machines available in your lab it could be possible to perform an analysis more than another. Of course some basic chemicals are in every lab, but to avoid misleading you it could be better to receive more information about the type of research you want to carry.
Please have a look at the following link:
Best regards
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What are the oil based inputs for production of bio-polyamides for application in textile sector?
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Mostly adipic acid, manufactured from hexane, and also 1,6 Hexane Diamine, also made from hexane. Or Caprolactam made from hexane.
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When comparing different Li-ion cells (no cooling) , what is the general trends in cycle life vs temperature? Across different Li-ion chemistries (NMC622, 532, NCA etc), is there a generic trend.
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Hi everyone,
I'm not able to find the correct citation style for Rubber Chemistry and Technology (ACS). I'm using the Endnote plug-in "Cite while you write" for Microsoft word.
The references should be superscript, listed by appearance order and edited using first name, surname. Such as:
R. B. Fox, RUBBER CHEM. TECHNOL. 68, 547 (1995). doi:10.5254/1.3538755
P. J. Nieuwenhuizen, J. M. van Veen, J. G. Haasnoot, and J. Reedijk, RUBBER CHEM. TECHNOL. 72, 27 (1999); 72, 43 (1999).
The "ACS-no title" citation style seems to be ok, but in the list, the surname appears before the name (as usual) and it is wrong.
Fox R. B., RUBBER CHEM. TECHNOL. 68, 547 (1995). doi:10.5254/1.3538755
Thanks for any advice,
francesco valentini
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It looks like neither the journal nor EndNote provide a style file, thus you will have to edit an existing style (perhaps ACS). If you have EndNote on your computer (not the plug-in but the stand alone program), go to Edit/Output Style/Edit "ACS"/Bibliography/Templates. Edit the journal article template, then save the edited style with a new name. When you reopen Word, you should see it when you "Select another style".
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We used the one step method in the lab to obtain FAME for our GC analysis.
Many time we see varying degrees of evaporation of solvent (BF3 and internal standard) from our test tube during the 1 hour heating.
We tried putting PTFE tape around the thread of the test tube but we have varying success rate.
How would you effectively prevent evaporation of solvent in a screw-capped test tube during heating in a water bath?
See here for the simplified method we used: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2593112/
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Dont worry. Dr Kafferlein. We are all here for discussion. That's no wrong or right answers. Thank you so much for your contribution.
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Using DCM as a solvent for functionalizing a gold/silicon substrate with a self assembled monolayer by immersion. I noticed that after while, the solution is turning cloudy. Why does that happen?
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It could be anything, from contaminants to side reactions/unexpected reactions. To check, I suggest eliminating one after another as follows:
Check the expiry date of the materials being used. Confirm from literature what/how you expect your mixture or solvent to look like at every step, if already published.
- Use well cleaned and completely dried glassware
If persists
- buy new solvent