Chemistry - Science topic

The molecule shown in the image is known as Argyrin G3, please propose a retrosynthetic analysis diagram showing disconnections and reasons for the disconnections. also please provide a synthetic route for the forward synthesis of Argyrin G3 including reagents and amounts. please provide sources as well if possible.

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

Ali

Is there any good chemistry book about heavy metal precipitation/ extraction via chemical / chelate method?

is it possible to calculate photoelectron Circular dichroism (PECD) using quantum chemistry?

in the matter of measuring the content of a certain component in botanical chemistry

Hello,

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!

Nikhil

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!

Greeting,

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.

Please help..

Hey,

I'm looking for an article that explains that inductive and resonative effects are components of pi bonds. That is what my PI claims.

Thanks.

Hi everyone!

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.

Pablo

Literature cited:

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??

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.

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.

Thank you!

Good day,

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.

Thanks

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.

Chemistry:

blood 2+

leukocytes 2+

pH 7.0

SG 1.009

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.

#Nanoparticles #chemistry.

Hello Scholars,

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.

Thank you

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,

B.P.

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 factors in the COD level caused the initial COD level to be very high?

Meanwhile, after being electrolyzed (after treatment), the COD level decreased, what caused the COD level to decrease and were there any structural changes that occurred related to the reagents in the electrolysis process (organic compounds, electrolyte, additional H2O2, COD reagents) .

So, for example, the sample is acetaminophen

Before treatment (acetaminophen + aquades), why was the COD level of the acetaminophen sample so high? what causes the high value? and why after treatment, the COD level of acetaminophen decreased? what causes the COD level of acetaminophen decrease? Are there any structural changes that occur in acetaminophen related to the reagents associated with the electrolysis process after treatment? if there is a change, what kind of change and how?

Thanks in advance.

How can a correlation be obtained from subatomic to superatomic? Why does the subatomic behave differently than the superatomic? Why does something that makes something behave differently from what it creates? Let's give an example to this first: Let's think of H2o water, hydrogen and oxygen: Here, hydrogen and oxygen atoms will behave differently from the water they form. So why is this? Is this due to the change in chemical structure? This means that the change in the chemistry of atoms under matter ensures that matter itself exists on matter. So what provides this? So what is it that changes the chemistry? How is it changing? So why does the thing that brings together this changing chemistry (structure) become matter? If the chemistry changes in the atoms under matter, what do we say if this matter is different from the substance itself, and since the submatter will normally form the above matter logically? If atomic chemistry, that is, subatomic, changes, it becomes supermaterial and they behave differently. Here we reach something: In contrast to atoms, there is something else under matter. In other words, apart from quantum, there is a structure under matter that interacts with atoms under matter and forms the upper part of matter. What should we call this:? Should we call it such a thing that it interacts with atoms and changes their structure and turns them into normal matter? So let it act in classical physics. So what makes atoms move in classical physics? Let's ask this. How do we determine whether something is in quantum or classical physics? If something moves relative to atoms, it's quantum. If there is something directly related to matter itself, it is classical physics. So what is it that differentiates atoms from what is directed directly at matter itself? Let's first explain the quantum theory: An atom could be in more than one place at the same time. So this would mean that an atom cannot be in more than one place at the same time when it interacts and changes chemistry. But what does it do? What kind of thing makes atoms lose this quality? What kind of thing in the universe loses the function of a particle being in two places at once? First of all, let's ask this: Being in two places at the same time;. It means being able to copy yourself and be able to influence at different points. So this thing, the thing that changes the chemistry, must have a function that destroys this quality. What thing in the universe reduces or eliminates influence at different points? What is the most influential thing in the universe? Matter is the answer, which occurs through this space-time warping. So as a result, Isaac Newton's m1.m2/r'2 formula gives us the output. As the distance between the objects increases; gravity (ie, space-time warping), that is, the twist by matter would decrease. In that case, as the distance between matter increases in the universe, the relationship that a substance establishes with submaterial and supermaterial brings us the existence of the supermaterial. Thank you.

In electrofenton, there is one method, namely electrochemical peroxidation, what are the advantages of this method so that it can degrade organic compounds? How is it different from electrocoagulation? what makes electrofenton/electrochemical peroxidation better than electrocoagulation?

Also, there are electrocoagulation and traditional coagulation, what makes electrocoagulation better than traditional coagulation? as well as the electrofenton and traditional fenton, why is the electrofenton better than the traditional fenton? What is the effect of Fe and H2O2 in degrading organic compounds? why when an electric current is applied the results are better? if there is no electricity, is it also good to degrade organic compounds?

Thanks in advance

What parameters play a role in the ability of amines to be protonated in water? Can the base strength of amines be a sufficient measure to compare the protonation ability of two amines? For example, is the protonation ability of n-butylamine more than morpholine?

Thank you

Hi everybody. I have a question about study kinetics. So, I did electrolysis by dissolving organic compounds with aquades as a sample under acidic conditions with Na2SO4 as electrolyte, with additional H2O2 (Fenton reaction) using iron as anode and graphite as cathode. In discussing the study of kinetics, I found that if the kinetic graph that R2 close to one or almost linear is in pseudo-second order graph, what does this pseudo-second order mean? what does pseudo-second order actually mean? i was told that "the pseudo explains that something is involved but doesn't appear in the rate law, for example the solvent or there is usually the fraction of the reactant that matters" is that true? So, if what is meant by second order is that there are two reagents that have an effect in this case, for example H2O2 and Na2SO4, but in pseudo-second order something is involved but it doesn't appear, what is it? also, if you also know, what kind of reaction mechanism that produces the pseudo?

Thanks in advance

Hello everyone!

I want to simulate a premixed combustion case with Hydrogen/air (or oxygen) chemistry.

I know simulating a non-premixed combustion case with hydrogen/air detailed chemistry means injecting hydrogen as fuel and air as oxygen at a particular temperature and pressure and using any available chemical mechanism (GRI, UCSD, etc...).

But, what is meant by simulating premixed combustion with detailed chemistry?

:I don`t understand this bold part

The mono- and bidentate bonding are formed via protonation of the surface hydroxyl group and releasing one water molecule, leading to a strong P-O-M bond.

Article title:Organic Hole Transport Layers for Efficient, Stable and Scalable Inverted Perovskite Solar Cells

doi:10.1002/adma.202203794

I saw this sentence .Hydroxyl group and amino group are the both nuclephilic. So no reaction will take place

I am carrying out a Research on the effect of blended learning on senior secondary school students achievement and retention in Chemistry. Could someone

help me with materials?

Hi there,

would like to learn more about appropriate material for the application of PPE in Epidemiology.

As all the material seems to be Polyethylene/Polypropylene, would love to learn, whether it is possible to use Polyamide material instead? Are the properties sufficient?

If Polyamide does the job, are normal Snowboarding and Fishing Overalls an alternative to the ordinary Hazmats?

Cherish your feedback.

Defining the dilution factor is very important when we are working at the level of ppb (parts per billion) or ppt (parts per trillion). Other day, I was working on plant biomass samples to analyze available Si (Silicon) in plant biomass. I have gone through several steps of dilution and became so confused about what is DILUTION FACTOR. I did several dilutions at several steps (digestion, adding chemicals, again diluting to come up with the range of AAS) and it became so complicated. As always, I approached Dr. Rafael Santos and he solved this problem very easily, I would say just in 10 minutes when I was struggling for an hour. Finally, Dr. Santos made a good explanation with their whiteboard and step by step he came up with the solution. Again, doing a Ph.D. is not just collecting and analyzing data but also needs to understand the chemistry happening in between. If you don't know how to do it then seek help. Asking someone doesn't mean your basics are not strong, asking someone means you know what you're looking for but you don't know how to approach it. I am thankful to have Dr. Santos as my mentor, peer and guide. PS: Here's complex whiteboard solution in the picture :) #ppb #ppt #help #academia #PhD #chemistry #data #AAS

Research chemists continue in their slow uptake of preprints. I've lately suggested one key reason for this unique behaviour of scholars in the basic sciences in two OA studies, one published by Publications:

and another by Insights:

What is your opinion on the origin of this delay? Has your team recently embraced preprint publishing? What are your favorite preprint repositories?

Thank you in advance for your insight.

Does anyone has an experience with sodium tert-butoxide? How dangerous it actually is?

Do I need to use a glovebox while weighting and handling it?

Do I have to dissolve it in THF at -30C or room temperature will also do?

How do you store it after the can is opened?

We have 100g of sodium tert-butoxide in total, the planned amount for my synthesis is ca. 1.5 g.

This is a graphical abstract image from one of the paper of eminent total synthesis chemist KC Nicolaou. Can anyone tell me how I can draw such type of image?

Please comment

Hi everyone!

I am working on different polymers and modifying them chemically and I want to write the chemical reaction. If I want to confirm whether the proposed chemical reaction is right or wrong, is there any software or something?

Thanks for your help!

Hi all,

To set things clearly: I am a PhD student working on the process implications of electryfing the ammonia production by replacing conventional SMR with Water Electrolysis. A part of my preliminary work is to assess the difference in theoretical minimum energy consumption. To do so, I have calculated a first approximation by summing up the reactions (SMR, Water gas shift, Haber-Bosch,...) and calculating the enthalpy of the resulting "total" reaction. I have done this for the "Water Electrolysis + Haber-Bosch scenario" and validated the minimum with values from the literature.

However, for the conventional "SMR + Haber-Bosch scenario", values from the literature are different. To be more specific, here is the energy minimum calculated in the following conference paper:

(...) the theoretical minimum of energy consumption for the process itself (represented by LHV of methane) is 22.2 GJ/t NH3 (...)

So here is my question: Why use the LHV of methane (instead the enthalpy of reactions) to calculate the energy minimum ? I feel like this is incorrect as I do not take into account the synthesis of methane.

Thanks in advance for any answers,

Antoine

Dear all

Hope you are doing well!

What are the best books in Materials Science and Engineering (Basics and Advanced)? Moreover, what are the best skills (or materials topic related) that materials scientists have to develop and to acquire?

Thanks in advance

^_^

This statement is claimed by

Simplistic notion of law of mass action or common ion effect cannot explain it . So what is the reason?

Please do not refer to the references on the paper

Kron I, Marshall SL,

May PM, Hefter G, and Konigsberger E (1995) The ionic product of water

in highly concentrated aqueous electrolyte solutions. Monatshefte für

Chemie 126: 819–837.

Dear all,

what are the possible instruments to use to obtain the purity of a powder (NaCl sold in a pellet form) (has 99% purity or above)?

the cheapest instrument to the expensive one if possible according to your experience

Thank you in advance

0.1 N concentration solution of both was taken, with HCl as titrant abd HPh as indicator. After reaching the endpoint of colourless condition, the colour reappears after continous shaking for 5 mins. even sometimes after 15 mins. How to be sure of that this much time is enough, for shaking to confirm completion of titration?

Good day,

i have a general question about tissue culture.

I have found the following recipe for Epipremnum Aureum "Marble Queen":

Leaf Explant: MS Medium + 4.54 µM TDZ + 1.07 µM NAA (Thidiazuron in Micropropagation of Aroid Plants by Chen and Wei (2018), p. 105, DOI: 10.1007/978-981-10-8004-3_4)

Specifically, I have the following questions.

1) Do i only need to autoclave the agar with distilled water (I use a pressure cooker for this) and when the agar has cooled down a bit just add the MS, TDZ and NAA and mix it or do i need to autoclave the MS as well?

2) Will the TDZ dissolve in the agar water at all and how hot can the agar water be to add the MS, TDZ and NAA?

3) Is it even necessary to autoclave the water incl. agar (in the pressure cooker) if I clean all the jars with NaClO (sodium hypochlorite)?

Thank you in advance!

"The general notion of an “RNA World” is that, in the early development of life on the Earth, genetic continuity was assured by the replication of RNA and genetically encoded proteins were not involved as catalysts. There is now strong evidence indicating that an RNA World did indeed exist before DNA- and protein-based life. However, arguments regarding whether life on Earth began with RNA are more tenuous. It might be imagined that all of the components of RNA were available in some prebiotic pool and that these components assembled into replicating, evolving polynucleotides without the prior existence of any evolved macromolecules. A thorough consideration of this “RNA-first” view of the origin of life must reconcile concerns regarding the intractable mixtures that are obtained in experiments designed to simulate the chemistry of the primitive Earth. Perhaps these concerns will eventually be resolved, and recent experimental findings provide some reason for optimism. However, the problem of the origin of the RNA World is far from being solved, and it is fruitful to consider the alternative possibility that RNA was preceded by some other replicating, evolving molecule, just as DNA and proteins were preceded by RNA." - Robertson and Joyce

[This is as per the explanation by Michael P Robertson and Gerald F Joyce in the article: "The origins of the RNA world." published in the Cold Spring Harb. Perspect. Biol. 4, a003608 (2012).]