Science topics: Chemistry
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
I am looking for a easy-to-use software, which can generate analogues based on one structure. I do not need to teach it what kind of activity compound has, I just need to have the structures generated so I can run it though QSAR (which was already set based on 80 compounds).
Does anyone have experience with this?
I would be grateful for any recommendations.
Irrational numbers are uncomputable with probability one. In that sense, numerical, they do not belong to nature. Animals cannot calculate it, nor humans, nor machines.
But algebra can deal with irrational numbers. Algebra deals with unknowns and indeterminates, exactly.
This would mean that a simple bee or fish can do algebra? No, this means, given the simple expression of their brains, that a higher entity is able to command them to do algebra. The same for humans and machines. We must be able also to do quantum computing, and beyond, also that way.
Thus, no one (animals, humans, extraterrestrials in the NASA search, and machines) is limited by their expressions, and all obey a higher entity, commanding through a network from the top down -- which entity we call God, and Jesus called Father.
This means that God holds all the dice. That also means that we can learn by mimicking nature. Even a wasp can teach us the medicinal properties of a passion fruit flower to lower aggression. Animals, no surprise, can self-medicate, knowing no biology or chemistry.
There is, then, no “personal” sense of algebra. It just is a combination of arithmetic operations.There is no “algebra in my sense” -- there is only one sense, the one mathematical sense that has made sense physically, for ages. I do not feel free to change it, and did not.
But we can reveal new facets of it. In that, we have already revealed several exact algebraic expressions for irrational numbers. Of course, the task is not even enumerable, but it is worth compiling, for the weary traveler. Any suggestions are welcome.
I prepare a chitosan solution in acetic acid (0.5 M). Some of the small threads are remained in the solution. In literature it is reported that solution is filtered before using. I want to know which filter is suitable for the filtration of chitosan solution?
I am using copper nitrate salt for my experiments. After 2 years, the salt crystals turned into liquid.
I am using copper nitrate trihydrate salt. Kindly let me know how can i store copper nitrate salt for long term?
I have performed drug repositioning to find antifungal activity. I need to explain the possible causes of why some drugs had antifungal activity and others did not. any suggestions?
There is some guide or ranking of the better congress of soils and chemical science?
Is there any good chemistry book about heavy metal precipitation/ extraction via chemical / chelate method?
Hello, I am fairly new to gromacs and molecular dynamics. I want to simulate thiols for starters for some applications and I want to generate the topology file for thiol. I found the PDB and ITP files for sulfanyl from ATB -
and I tried to use ‘pdb2gmx’. I have read up on the documentation but I can’t get it to work. I am stuck on how to modify a forcefield or how to simply create a new one for the molecule. Any help on how to generate the topology and gro files would be appreciated. Thanks
In the Column treatment of aqueous solution of Chromium Removal by Adsorption
What is the effect of diluent in nitrosamine recovery?
Candesartan Cilexitil is insoluble in water but we are getting good recovery in water and not in methanol for certain nitrosamines (NDIPA, NDPA). Can anyone suggest chemistry behind that?
Although formed over thousands of years, carbonate ramps forming where ocean sediments accumulate multicellular algae may be affected by ocean chemistry in such a way as to have a unique morphology.
How are deep ocean currents affected by these types of occurences? How is the ocean chemistry equilibrating alobg these geographies?
Do current terrestrial models incorporate data and equations to reflect these types of changes to a static estimation of the biosphere?
Do climate model researchers incorporate models of ecological regions underwater?
Advantages and disadvantages of teaching chemistry through elective courses. Increasing students' interest in chemistry through elective courses. Organization of elective courses in chemistry. Scientific-pedagogical basis of creating the elective course "Polymer materials". Scientific-pedagogical basis of creating the elective course "Ion exchange materials".
Como es posible solubilizar una membrana de colágeno sin perder la propiedad química del colágeno?
I am a PhD student in Chemistry.
- For drawing chemical structures, I have tried using some random softwares like Kingdraw, etc, but the GUI does not seem appealing and not easy to use overall.
- I have used sometimes the well-known softwares such as ChemDraw and ChemSketch in someone else's device, but I am unable to install them on my device in a straight-forward manner.
- I am looking for the list of the best drawing tools (softwares/freewares) which are easily accessible and will faciliate to draw better quality chemical structures, good enough for publications in peer-reviewed journals.
- Your help, suggestions, feedbacks, links are highly valued and appreciated from my end.
With Many thanks,
Janaki Devi Somasundaram
Good morning everyone. They know some pages about virtual chemistry laboratories, with special attention to high school education.
I am a researcher in chemistry, in which I have to use Pd as a catalyst. In every reaction, I have to change the millimoles of the reactants. But I can't understand how to calculate the millimoles of catalyst that should be used in a reaction according to millimoles of reactants or according to millimoles of the reactant on which the catalyst is attached during the reaction mechanism.
I know that some UK universities can provide PhD by publications in medical sciences, but I cannot have idea about which universities worldwide that provide PhD by publications in chemistry.
Please let me know if there is any information
Please spread the word: Folding at Home (https://foldingathome.org/) is an extremely powerful supercomputer composed of thousands of home computers around the world. It tries to simulate protein folding to Fight diseases. We can increase its power even further by simply running its small program on our computers and donating the spare (already unused and wasted) capacity of our computers to their supercomputation.
After all, a great part of our work (which is surfing the web, writing texts and stuff, communicating, etc.) never needs more than a tiny percent of the huge capacity of our modern CPUs and GPUs. So it would be very helpful if we could donate the rest of their capacity [that is currently going to waste] to such "distributed supercomputer" projects and help find cures for diseases.
The program runs at a very low priority in the background and uses some of the capacity of our computers. By default, it is set to use the least amount of EXCESS (already wasted) computational power. It is very easy to use. But if someone is interested in tweaking it, it can be configured too via both simple and advanced modes. For example, the program can be set to run only when the computer is idle (as the default mode) or even while working. It can be configured to work intensively or very mildly (as the default mode). The CPU or GPU can each be disabled or set to work only when the operating system is idle, independent of the other.
Please spread the word; for example, start by sharing this very post with your contacts.
Also give them feedback and suggestions to improve their software. Or directly contribute to their project.
Folding at Home: https://foldingathome.org/
Folding at Home's Forum: https://foldingforum.org/index.php
Folding at Home's GitHub: https://github.com/FoldingAtHome
Additionally, see other distributed supercomputers used for fighting disease:
Rosetta at Home: https://boinc.bakerlab.org/
I am currently planning some lab work that requires me to dissolve tris(2,20 -bipyridyl) ruthenium(III) chloride hexahydrate dye in a solvent in order develop a calibration curve relating phosphorescence lifetime and quencher concentration (In this case O2 is the quencher). I'm currently trying to figure out what solvent is best for the application. My background is in biomedical engineering and not chemistry, so my reasonably basic knowledge chemistry is not much help!
I had considered water as a solvent but figured the presence of dissolved O2 would potentially lead to inaccuracies in the oxygen concentration for the calibration curve. If I used a Schlenk line of nitrogen to remove the dissolved O2, would degassed water be a viable option for the solvent?
In regards to mixing O2 with the solvent and maintaining a desired O2 concentration within the solution, I have read articles where a mass flow controller was used to achieve desired O2 concentration, can anyone confirm this method? Any suggestions / guidance is greatly appreciated!
I’d like to determine the monomer conversion through gel fraction. The experimental process I read in some papers was described in a simple way, omitting some details. I wonder how to filter the soluble substances and the insoluble one? In what way?
I want to deacetylate the chitosan in sodium hydroxide (50 % w/w) solution. Does that mean 50 g NaOH in 50 mL of distilled water? What should be the appropriate time and temperature for the complete process? There are different temperatures and times are reported in literature.
Thank you for your help!
I am trying to optimise an organic molecule using Avogadro software, and when I draw the molecule according to the correct sterochemistry (some bonds coming towards the screen and some going away from the screen) whenever I optimise the molecule using one of the forcefields the stereo chemistry starts to change and therefore some bonds face the wrong plane, is there a way to optimise the molecule without changing its stereochemistry in avogadro software?
I made several reactions with 3,5-Dinitrobenzoyl chloride. When I looked at similar reactions for this substance, no heat was ever given in the reaction (even though heat increases the yield).
The interesting thing is that this substance turns black as soon as the heat is given to the reaction environment. Due to the fact that, theoretically, the polymerization of this material is impossible. Do you know the reason why they do not give heat to this material?
If we have a crystal with a coordination number of five, triangular bipyramidal(TBP) and square pyramid(SP) are expected. An intermediate state may also be obtained due to Barry's pseudo-rotation. But if the crystal data did not match any of the structures and the shape deviation was excessive, what structure should be reported? I also used the following formula, but it didn't work. What structure should I report?
•Pictures from reference, Chemistry of coordination compounds by M.M.Pouramini, N.Safari, K.Darzinezhad
Using DFT, I have a graphene system with Nitrogen doping. It is well known that the nitrogen covalent bonds with 3 sp2 hybridized carbon atoms. When placing this system on top of an Silica which contains Si surface atoms having sp3 hybridization (Si has one free electron), the Nitrogen creates a covalent bond with Si.
My question is, what happens to the lone pairs in nitrogen ? How can it bind with the electron in Si even though it has lone pairs.
in the matter of measuring the content of a certain component in botanical chemistry
How many grams of K2Cr2O7 to dissolve it in 1 liter Distilled water to obtain 50 ppm of Chromium? to become aqueous solution, Is there a specific equation to apply? Thanks
is it possible to calculate photoelectron Circular dichroism (PECD) using quantum chemistry?
I need to take the sodium nucleotide salts I have available in my lab and modify them to instead contain some more exotic counterions. Can I do this by binding my nucleotides to a strong anion exchange resin, washing, and eluting with a salt of my preferred counter ion?
Thanks very much!
I want to prepare 2% solution of chitosan using 0.5 M acetic acid but need to adjust pH to 4. How can I do that? I added NaOH to the chitosan solution, precipitates were formed in chitosan solution.
Some Oxford Nanopore kits have Primers with 5 ' modification that provide ligation to adapters without the need for ligases (ligase-free method), as in 16S barcoding kits. Does anyone know what modification this is or the chemistry involved in the process? I'm very grateful if anyone can help me with this information. Thanks.
If I want to synthesize the product shown in the image, would it be faster to use option A as the starting material or option B. My goal is to synthesize the product in the space of 4-5 hours, which is the best option to use? also what reagents should be used for the synthesis? i was thinking of mixing the starting material with dry methanol and then adding TMSCl while the solution is in an ice bath then removing the mixture from the ice bath and stirring till the reaction is complete. the issue I have is that this reaction usually would take much longer to complete. what is the best way to approach this problem?
Some researchers say the type of surface electrical charges effects on pH value of the reaction medium and thus the adsorption and removal process , when pH value increases, the overall surface electrical charge on the adsorbents become negative and adsorption process decreases, while if pH value decreases, surface electrical charge become positive and adsorption process increases
Malkoc, E.;Nuhoglu, Y. and Abali,Y. (2006). “Cr (VI) Adsorption by Waste Acorn of Quercus ithaburensis in Fixed Beds: Prediction of Breakthrough Curves,” Chemical Engineering Journal, 119(1): pp. 61-68.
I admitted as an undergraduate to multiple universities in Arizona and Colorado! I have been actively looking for admission to the university to continuously prepare me as an investigator/innovation scientist in mineral exploration by building my foundational knowledge in metallurgy, chemistry, control systems engineering, geochemistry, geophysics, etc. These might be included in my coursework. My focus may be on "control system engineering" compared to "geoscience," as I want to spend my effort investigating sensor innovation using metallurgy, geophysics, chemistry, etc. for mineral exploration. Precisely, investigative research will be on creating "detection technology for purposing of Mining exploration and extraction" So, I'm confused with two queries: 1. Which university would be the best option based on my research interests? 2. Which major and region for internship/ real time research job corresponds to what I'm actually looking for?
Hope you already understand I’ve applied many universities with getting rejection that didn’t also find exact research team yet I’m looking. Thank you so much.
Hello All! I am working on a project that uses stable isotope analysis (C and N) to look at the diets of California reef fishes. I am going to be collecting Liver and White muscle tissue. It was suggested to me to use 20ml borosilicate glass scintillation vials (urea caps with polyurethane lined caps/not foil lined) for my tissues. I will be freezing the tissue samples in the vials and drying them in a 65C drying oven in them as well. The issue I am running into is that every brand of vials are back ordered for about 4 months no matter where I look.
So I wanted to see if 1. Anyone in the southern California/greater LA Area had vials I could buy off of them to use. Or 2. If anyone knew of a substitute I could use. It has been suggested that I could hand make aluminum foil packets, pre combust them, and store/dry the tissue in those. However, I would prefer the glass vials for both, organization/storage sake as well as I will eventual be grinding the powder into a powder and vials would be less likely to fail with the powder.
Thank you in advance for any advice!
When I tried to remotely accessed the scopus database by login into my institution id, it kept bring me back to the scopus preview. I tried cleaning the cache, reinstall the browser, using other internet and etc. But, none of it is working. As you can see in the image. It kept appeared in scopus preview.
I'm looking for an article that explains that inductive and resonative effects are components of pi bonds. That is what my PI claims.
I project to measure levels of total phenolic compounds in peppers following the method of the Folin-Ciocalteu's reagent, and I am going to calculate them by reading absorbance using gallic acid as a standard.
Nevertheless, I am confused about what wavelenght should be setted: while some authors read absorbance at 765 nm (Dogan et al., 2018; Kupina et al., 2018); others read it at 760 nm (Ghasemnezhad et al., 2011); 750 nm (Toledo-Martín et al., 2015; Lwin et al., 2022) or even 725 nm (Vega-Gálvez et al., 2009).
I would be grateful if someone could give me some light about this.
Thanks to everyone in advance.
Dogan, A.; et al. (2016). Comparison of pesticide-free and conventional production systems on postharvest quality and nutritional parameters of peppers in different storage conditions. Scientia Horticulturae 207: 104-116.
Ghasemnezhad, M.; et al. (2011). Variation in phenolic compounds, ascorbic acid and antioxidant activity of five coloured bell pepper (Capsicum annum) fruits at two different harvest times. Journal of Functional Foods 3: 44-49.
Kupina, S.; et al. (2018). Determination of total phenolic content using the Foling-C assay: Single-Laboratory validation, First Action 2017.13. Journal of AOAC International 101 (5): 1466-1472.
Lwin, H.P.; et al. (2022). Perforated modified atmosphere packaging differentially affects the fruit quality attributes and targeted major metabolites in bell pepper cultivars stored at ambient temperature. Scientia Horticulturae 301: 111131.
Toledo-Martín, E.M; et al. (2015). Application of visible/near-infrared reflectance spectroscopy for predicting internal and external quality in pepper. Journal of the Science of Food and Agriculture 96: 3114-3125.
Vega-Gálvez, A.; et al. (2009). Effect of air-drying temperature on physico-chemical properties, antioxidant capacity, colour and total phenolic content of red pepper (Capsicum annuum, L. var. Hungarian). Food Chemistry 117: 647-653.
I will use DFT calculation tool, MedeA VASP, for calculating Gibbs free energy of gas phase and solid phase.
I know that gas phase calculation using VASP may be uncorrect. But I can't use Gaussian because of the budget.
MedeA VASP Phonon module gives below data
1)Cv : vibrational heat capacity at constant volume 2)E_vib(T)=E(T)-E(0) : the change in vibrational internal energy from 0 K, where E(0) = E_elec + ZPE is the electronic energy of formation E_elec plus the zero point energy ZPE 3)S(T) : the vibrational entropy at temperature T 4)-(A(T)-E(0)) : the change in the vibrational Helmholtz free energy from 0 K 5)E(T) : the electronic energy of formation plus the vibrational internal energy, so this term is E_elec + ZPE + E_vib(T)
6)A(T) : the electronic plus vibrational Helmholtz free energy, E(T) - T.S(T)
and my questions are
1)How can I calculate Gibbs free energy for gases and solids from these data?
(I know that in a gas we can regard the internal energy as the sum of the electronic, translational, rotational, and vibrational energies. And We just get electronic and vibrational energy. Also, How can I consider PV term?)
2)How accurate is the VASP transition state and thermodynamic calculation for gas?
(I will calculate reactions for CVD reaction. ex)SiH4+SiH4->SiH6+H2, Si(wafer)+SiH4->Si+H2, etc.)
Usually, plant phenols are best extracted with solvents like methanol and ethanol. But I would like to know if the extraction is carried out with water, how much usually is the efficiency of that extraction??
In the following article's ESI, it seems that in situ decomposition of 2,5-Dihydroxy-1,4-benzoquinone (DHBQ) lead to the formation of oxalate under hydrothermal conditions.
Can someone explain the mechanism/pathway behind it?
Ref.: Science 374, 1464 (2021)
Please correct me if I am wrong by any chance.
Thanks in advance.
I want to apply Post-doc Chemistry in Turkey. Can anyone suggest me a University in Turkey???
Hello! What are the oldest literary sources you know that would mention pharmaceutical salts? I am aware of the first cocrystal [benzoquinone + hydroquinone] (1:1) investigated in 1844, but I could not find any mention of the first (or even the first described) pharmaceutical salt (Wohler, F. Untersuchungen über das Chinon / F. Wohler // Ann. Chem. Pharm. – 1844. – V. 51. – P. 145-163). If you know of such sources, please share them. Thanks in advance
I would like to generate a *.sdf file like those posted NIST Chemistry Webbook from a *.log or *.chk Gaussian 16 file and cannot immediately find how to do this. Many thanks for helping me.
Which software is best for making high-quality graphs? Origin or Excel? Thank you
Mehlich-3, 20 L final volume:
0.2 M acetic acid (230 mL concentrated glacial acetic acid, ACS)
0.25 M NH4NO3 (400 g ammonium nitrate, ACS)
0.015 M NH4F (11.1 g ammonium fluoride, ACS)
0.013 N HNO3 (16.5 mL concentrated nitric acid, ACS)
0.001 M EDTA (5.85 g EDTA free acid, ACS)
Purpose: Soil nutrient extraction for boron, copper, zinc, phosphorus, iron, manganese, magnesium, potassium, calcium, and sulfur to be measured by ICP-OES.
Once all compounds are combined and dissolved, my Mehlich-3 extractant has a pH of approximately 3.2 instead of the pH 2.5 the SOP I'm following indicates the extractant should be. Should the unadjusted pH of the extractant be 2.5 and, if not, what acid would be appropriate to adjust the pH without impacting extractant performance?
Some preparation instructions suggest making a 3.75 M NH4F + 0.25 M EDTA free acid stock solution and adding a volume of that rather than adding NH4F and EDTA directly to the extractant as I'm doing above but I've never managed to get the EDTA to dissolve after dissolving the NH4F using that approach.
If anyone can assist me, please. How do you measure ammonium and nitrogen from urine? what is the best simple method for someone who is new in chemistry if you can recommend the site where I can find the experiment of measuring ammonium and nitrogen would really appreciate it.
How long does it take to a journal indexed in the "Emerging Sources Citation Index" get an Impact Factor? What is the future of journals indexed in Emerging Sources Citation Index?
We can test an antagonist e.g. at 10uM with varying concentrations of agonist. We can then use Schild/gaddum equation to find a KD (also known as KB) for the antagonist.
If i was to change antagonist concentration to some other concentration like 100nM, but test with same agonist, will the KD calculated for the antagonist change or not
If someone is granted with utility model can he/she claim it to be granted a Patent?
Is it legally acceptable?
Data augmentation techniques drastically improved AI models while dealing with images and text, however, it is not so obvious how to translate these approaches to chemistry and materials science. What methods do you know and how legal do you think they are?
I have some flyash and want to leach out Al2O3 and SiO2 using NaOH. IS there any additive which can help me to improve rate of leaching or dissolution .
We talk about the round oval shape objects. Grid is 15 um. We supossed some kind of drug crystals, but patient has no special medication.
Hello everyone. I need a little help here.
can we use essential oils to reduce chlorinous odor in a hypochlorous acid solution without decreasing free chlorine or pH value? any toughts and propositions are much appreciated
Hi, I need to make an optical window 0.5 - 1mm thick and 6 mm in diameter from PMMA. I would really want to master the skill of production instead of buying some slug or film sheet because later would need to modify the shape ( make a wedge instead of a plane window ) and so on.
I am planning to make a mold using a 3d printed circular part ( see the drawing attached ) wedged between two microscope slides.
We gave it a try and made a sample, but at that time we didnt have the vacuum chamber and poured the pmma into the could mold. ( see the picture attached )
The problem is that the fist sample was quite large and separated from the glass rather easily, which is not the case for smaller sample. The second problem is bubbles.
Could you please suggest the exact step by step scheme to follow ( the concentration, temperature mode, time frames and so on ) to improve our results and obtain bubble free sample which can be safely parted from the mold after the hardening.
What I have:
1. Methyl methacrylate (CAS Number: 80-62-6) from sigmaaldrich
2. Azobisisobutyronitrile (CAS Number:78-67-1) from sigmaaldrich
3. magnetic stirrer hot plate, beakers, vacuum chamber, heating chamber
Thanks a lot in advance.
I have synthesized cerium oxide nanoparticles (CeO2 NPs) using the combustion method. My attempts to functionalize the NPs using the APTES have failed so far. After APTES functionalization, the particles are not stable; they settle rapidly. I would greatly appreciate it if someone could propose a solution and reason to the problem.
I am an undergraduate at the University of Cross River State, Nigeria currently pursuing a microbiology program. For familiarity and enhanced understanding of the course, I wish to seek recommendations on the virtual/simulation laboratory software that would be very helpful to me and my colleagues. With my interest in research too, I will be pleased if a research simulator is recommended to help widen my understanding of Microbiological research.
Your recommendations would go a long way to significantly contribute to my academic career as well as my colleagues.
I'm finding some cationic molecules like below.
I tried finding on www.sigmaaldrich.com , but couldn't find anything.
Where can I buy some molecules like this?
ref)Ikeda, Taichi, and Yoshitaka Matsushita. "Tetrahedral Tetra-cationic ionic liquids." Chemistry Letters 49.1 (2020): 14-16.
I will be working on a slow-release fertilizer for my undergraduate thesis, but I am confused about how other authors measure cumulative nitrogen release for a time interval (including the instruments and calculations)?
More exactly how they measure the exact nitrogen released each time.
Please provide a step-by-step process for a rapid water test.
-Thank you for helping a chemistry student.
I wonder if the removal of pi bond and the addition of heteroatoms such as halogens would increase or decrease the energy gap between the ground state and excited state of the electrons.
We are living in a world where recently Artificial intelligence is being used in many applications for prediction of many events and things. We all know that the amount and balance of certain Chemicals in the brain have a role in causing us think creative , feel emotional or happy etc. I would like to learn the valuable opinions of Scientists on what specific roles Chemistry would have in creating human conciousness ?
Salt has an ionic bond. It's chemically bonded. So, when it dissolves in water, the ionic bond is somewhat lost. But, people argue that it is a physical change because-:
a) The mixture of salt and water can be separated by evaporation.
b) No new substance is formed.( how though? isn't salty water completely different from just water or salt alone?)
c) There is no energy produced. (but then again when we tear paper, the ripping creates some energy...so how is there no energy in a physical change?)
Thank you in advance,
thanks in advance on sharing the method
I am evaluating the options, especially in the true open-source world, for making reliable calculations with high-accuracy using quantum correlation methods.
I synthesized a molecule. I want to know what are the self-assembled structures possible for it through hydrogen bonding.
If possible, please suggest me some free software available (installation-based or online)
Any relevant suggestions are highly appreciated. Thanks.
Hello, I recently discovered via GC-MS that my sample contains crown ether. This was really unexpected. I would like to know how to isolate these compounds for further analysis. I appreciate any paper suggestions or personal tips!
Who is your nominate for the chemistry and physics Nobel prize?
Chemistry question: I've received compounds to dissolve at 10uM. They sent MW, FW, and mg amts for each. Some cpds MW=FW, but others have "salts" added, and those have FW>MW. Should I use MW or FW to convert the mg amt to moles for calculations to achieve uM solutions?
Please Suggest me research topic for bachelor degree of chemistry
self‐assembly in the crystalization process.
The origin and the first study in the field of self‐assembly
Hello everyone, I have a question about COD (Chemical Oxygen Demand) electrolysis of organic compounds. When doing the COD analysis of the initial sample before treatment, why did it produce a high COD level? what fa