Science topics: Chemistry
Science topic

# 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
Question
Hi all
I have an equation of the form CxHyOz---->(decomposition) aCO + bCO2 + cCH4 +d H2
how can i get the values of a, b, c and d from elemental and proximate analysis of biomass?
x,y,z are unknowns
Thanks
You can use BS EN 15104:2011 Standard by CHN instrument.
Also, refer to scientific articles about biomass analysis.
Best Regards
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I want to do a chemistry between two compounds. Only the amine groups of both these compounds are free for conjugation with each other. What linker is best suggested for the process?
There's many ways to do this. This is a classic problem in bioconjugation chemistry. I highly recommend to look at the following link or Hermanson's textbook on Bioconjugation.
I agree glutaraldehyde is easiest way but often leads to polymerization, which can be controlled by reducing the glutaraldehyde concentration and also carrying it out in a cyanoborohydride coupling buffer. All reactions have side reactions but there are conditions that you have to identify that increase the selectivity of a desired reaction.
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I researched two highly cited journals publications (2017-2018) and observed that more than 55% papers on very specific research topics are published by 13 research groups from 5 countries. Is really only 13 research groups are capable for the highly cited research load of the world?
This is a very good question.
In my opinion, the whole process "of conducting research, publishing it, and citing" is moving towards being more politicized. They may call it globalization but, apparently, this is a sort of colonization in which research endeavor in certain areas cannot progress unless it follows the lead of specific groups in other "far" countries. This way, the "masters" can be sure that they stay at the top while the others lag behind.
The story is much longer with many details... a good follow-up is required for writing a "review" or a "book" on this subject & the researcher can support it with statistics & figures.
Question
what exactly the NaCl does to the surfactant means what is the chemistry involved ? Does it have any relation with the CMC ?
Ionic surfactants:
Electrolyte (e.g. NaCl) decreases the cmc. Theoretical treatments have related this to the thickness of the electrical double layer surrounding the micelle. This reduces the repulsion between the head groups.
An empirical relationship for the electrolyte effect was given many years ago by Corrin and Harkins: log(cmc) = -a.logC + b,
where C is the total counterion concentration. The constants a and b depend on the ionic head and the temperature. [Original paper: J. Amer. Chem Soc. 69, 683 (1947)]
An example of the magnitude of the effect is our data for a commercial alkane sulfonate: cmc about 0.4 g/L without added electrolyte cmc about 0.02 g/L in 0.1 M KCl [Tenside Surf. Det. 47, 28-33 (2010)]
Nonionic surfactants:
The changes in the cmc are generally smaller than with ionics and are thought to be due to the effect of the electrolyte on the hydrophobic groups (salting out or salting in). However, there will presumably also be some interaction with the hydrophilic group.
Question
Hi all,
I have some confusions regarding ultimate (elemental) and proximate analysis
1) Should the sum of all percentages be always 100 (for both analyses)?
(Figure 1 attached, doesn't make sense to me)
for balsa wood, C+H+N+S=100
for Eucalyptus, Ash+C+H+N+S+O=100
for rice husk, Ash+C+H+O=100
2) Is ash included in elemental analysis?
3) Is elemental analysis always based on dry/wet basis. what should we consider (dry or wet) if not mentioned?
4) If in elemental analysis, sum of all elements percentages equals 100, and humidity is also given (additional to 100%), then what is it, dry or wet basis elemental analysis? (figure 2)
Thanks
Dear Sir. Concerning your issue about the elemental and proximate analysis, wet and dry basis . In the proximate analysis, moisture, ash and volatile matter are determined. There are standard tests to determine proximate analysis. Moisture is determined by drying 1gm of sample at 105o C for 1hr. Weight loss is expressed in % of initial weight of sample. The main chemical elements in coal (apart from associated mineral matter) are C, O, H, N and S. The chemical analysis is very important to calculate material balance accurately and calorific value of coal. I think the following below links may help you in your analysis:
Thanks
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Hi,
I tried the hummer's method with the steps mentioned below but the FTIR didn't showed peak for GO it only showed the peaks of graphite and other impurities groups. What could be the possible reasons for absence of GO formation?
My steps of hummer's method:
1) Poured 2g graphite flakes in 50 ml H2SO4(98.5%conc.) and stirred it. The temperature was kept below 5 degrees celsius.
2) After some minutes of stirring 2g NaNO3 was added to the solution and the solution was stirred for 2 hours.
3) Now 6g KMnO4 was added to the solution very slowly and temperature was maintained below 15 degrees celsius.
4) The ice bath was removed and the solution was stirred at room temperature for 48 hours. Actually the hot plate was not working properly so I was unable to set its temperature at 35 degree celsius. The temperature of the solution was some what 38 degree celsius when I checked it with thermometer. The colour of mixture changed to dark brownish and I observed that due to viscosity the stirrer was only able to rotate (stir) the mixture from center and thick mixture was sticked to the wall of flask.
5) After 48 hours of stirring 100 ml of DI water was added to solution and temperature reached to 95 degrees.
6) After stirring a couple of minutes at 95 degrees I added 200 ml of DI water and temperature dropped from 95.
7) Again after some minutes of stirring I added 15 ml (30% H2O2).
yellowish colour was observed only at the top of mixture. Below the mixture was brownish.
8) The mixture was then left overnight.
9) For washing the mixture was centrifuged at 8000 RPM first for collecting the particles.
10) The mud like pulp was then washed two times with DI water and one cycle with mixture of 1/3rd methanol and 2/3rd DI water at 8000 RPM.
11) Sample was then dried overnight in petri dish at 80 degree celsius on a water bath.
Kindly guide me dear members what went wrong in the whole process.
I suggest Dr. Richa Bhagavea answer. Also
(i) Add KMnO4 very slowly-during that time it becomes greenish
(ii) After adding H2O2 it becomes yellowish
During the preparation of GO, every color changes indicates the proper oxidation.
Question
I'd love to see a rough sketch of how the task would go.
Critical thinking should be insipulated - and even enforced - at every stage of education. Nowadays, learning to learn only by heart is pointless. The ability to think critically gives you the necessary flexibility and allows you to adapt to changing conditions, allows you to critically perceive the world. During classes with students, it is important to inspire you to express your own opinions, ask questions even in seemingly obvious situations. For self-thinking and a unique approach to a topic should be some bonus to encourage.
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Question
Hi, I wanted to study cysteine level in animals feed, however, HPLC equipment is not available here.
I found this colorimetric method (link at the end of the question) online, but it was published in 1998.
I wonder if anyone done anything similar and can share their valuable advice with me or if you know an improve and better method than this, please let me know too.
Million thanks.
I think that in order to get a truly selective and quantitative measurement of cysteine in a complex mixture such as animal feed, some sort of separation method will have to be used to isolate the signal for cysteine from signals due to other substances.
A very simple colorimetric method for measuring the concentration of total thiol groups, including cysteine (but not cystine or cysteic acid), is to use Ellman's reagent. For this procedure, however, you will have to produce a clear extract of the feed. Also, it seem likely to me that cysteine in animal feed would be oxidized, so would not be present in the reduced form and would therefore not react with Ellman's reagent. In that case, you would need a method that can measure the oxidized forms of cysteine.
Here is a fluorescence-based assay kit for cysteine thiol that is not affected by other thiol-containing amino acids. It is intended for use with serum or other biological fluid.
To measure both cysteine and cystine (and other thiols), you could first reduce the cystine to cysteine using TCEP, then react the thiols with a fluorogenic maleimide such as coumarin phenyl maleimide (https://www.thermofisher.com/order/catalog/product/D346), which does not require removal of the TCEP.
Question
Evaluating academic faculty for promotions often include assessing their teaching abilities. Is it sensible to base these on Student Course Evaluations?
Geoffrey Alderman wrote in the Gaurdian that a reason for the decline in academic standards has been the 'increasing and increasingly stupid use of students' course evaluations as pivotal factors in the academic promotion process.'
Does anyone have a deeper insight on how the use of such student evaluations have impacted faculty at their own institutes? Have they led to dumbing down?
How much confidence would you have in the teaching ability of the applicant if the evidence was exclusively based on Student Course Evaluations?
I agree with so many of the comments, if they are to be used, they must be just one element in the evaluation process. If they are administered and collected, they must have a purpose. They should be a resource to potentially identify problems within the instructional setting, but not as confirmation of a problem. Validation only after a deeper examination into a possible issue.
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I'm not an expert in chemistry but I hope it to be a straight forward question.
The situation is, as shown in the figure below, I'm trying to etch a semiconductor in KOH solution (4M concentration) at room temperature. There is a negative sheet charge with a density of P (C/cm2) located at the bottom surface which repels the OH- from accessing the semiconductor. However, the etching can progress along the sidewall until the distance (d) is too close and the diffusion force and electric field reach an equilibrium. I'd like to know how to calculate this distance d. Thanks in advance.
You have OH ions, then quantified via pOH.
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I am interested in new Sn(IV) based products, without a direct bond to a C-atom , what makes these products not toxic.
Is your work going into this direction , or is it more for anti-fouling applications?
Best regards,
Dr.Joop Koster
JBK Research & Consulting
CH-1260 Nyon
Switzerland .
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I am looking for a procedure of determining nitrates and phosphates in water samples using UV-Vis.
Lokesh Kumar has said it all. I cannot add to that.
Question
By best, I mean which could easily extract out soil organic matter such as amino acids plus which could easily be available or synthesised using basic chemicals.
A new soil extractant (H3A) with the ability to extract NH4, NO3, and P from soil developed and tested against 32 soils, which varied greatly in clay content, organic carbon (C), and soil pH. The extractant (H3A) eliminates the need for separate phosphorus (P) extractants for acid and calcareous soils and maintains the extract pH, on average, within one unit of the soil pH. The extractant is composed of organic root exudates, lithium citrate, and two synthetic chelators (DTPA, EDTA). The new soil extractant was tested against Mehlich 3, Olsen, and water for extractable P, and 1 M KCl and water‐extractable NH4 and NO2/NO3. The pH of the extractant after adding soil, shaking, and filtration measures for each soil sample.
1. Morgan Extraction Reagent which was introduced in 1941
2. Mehlich introduced an universal extractant, frequently referred to as the Double Acid extractant, for assaying acid sandy textured soils.
3. The ammonium bicarbonate‐DTPA extraction reagent for use on alkaline soils was introduced.
4. Wolf modified the Morgan extraction reagent by adding DTPA to it. In 1984, Mehlich described his Mehlich No. 3 extraction reagent for use on a wide range of acid soil types.
All above extraction reagents can be assayed using a multielement analyzer such as the inductively coupled plasma emission specterometer for both the major elements and micronutrients in the obtained extractant.
The soil extract can be prepared by mixing 5g of soil in 1L H2O mix well, filter and then autoclave.You don't have to use soil extract to isolate Actinomycetes you can use any other medium that contained two different antibiotics for inhibition of fungi such as nystatin and streptomycin for inhibition of bacteria.
Question
I was wondering if anybody has worked with chemistry of these two cross-linkers and have characterised by FTIR or MS whether they are cis/trans or S/R isomers?
Apologies: I am not a synthetic chemist by training.
does the diminution of cis and trans in elastomer indicate scission ? (abstraction of hydrogen)
Question
Hi,
I am trying to modify sulfonic acid group to conjugate with carboxylic group or amine group in protein.
I have hard time finding chemistry to modify sulfonic acid for the conjugation.
Can anybody let me know if there are options?
Thanks
best,
The conditions of reaction depend on the structure of your compound containing -SO3H group. I think that you should check methods using SOCl2 or PCl5. The disadvantage is that these reagents can also react with hydroxyl and carboxyl groups.
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I am wondering if one could ideally create a formula inputting the stokes/hydration radius of the ions involved and the charge of the ions to estimate the change in melting/boiling point of water per gram of salt used?
I am not sure if a direct correlation can be made using the hydration radius, but my intuition tells me that an ion which strengthens the hydrogen bonds between the water molecules (like e.g. Lithium which has a large stokes radius) should be able to increase the boiling point of water by a few degrees, whereas an ion which destabilises the hydrogen bond cluster (and therefore has a small stokes radius) like Rubidium should decrease the melting point of water.
The presently available theories of aqueous ionic solutions are too crude to deal with problems of the sort you address and limited to very dilute solutions.Ionic size definitely affects colliigative properties and phase equilibria at higher concentrations since it is a first order measure of the specific local interactions of an ion with hydration waters in addition to the ubiquitous screened Coulomb interactions crudely treated via Debye
Hueckel like theories and the ionic strength concept.Unfortunately computer simulations of dilute to moderate molality salt solutions are also
not feasible due to the long range Coulomb interaction and the complex nature of water and ion water interactions.For the time being one has to resort on fits of experimental data etc.
Question
There are many predatory journals online available and also growing day by day. How to detect that the journal is predatory, As I found there is site where there is list of predatory journals but how we will come to know these sites information is correct or not?
Any other way to find out?
As there is continuous threat that somebody may waste their data in publishing in these journals.
The best, I found with all the information, that we check with thompson reuter.
Please follow the link below for the all journal list, which are peer reviewed and indexed with Thompson reuters
Question
I am preparing an optical system in infrared, however I will need to stick two optical components. They are made from CaF2.
Can you recommend index matching-liquid? I am interested in the range 1um-15um. I see that other researchers use paraffin oil, but still i would like to make sure of all possibilities.
Or maybe there are few liquids, that would work eg. in 1um-5um, 5um-10um and so on?
A few came to mind, but none is perfect. You will need to choose based on your application. Each of these below has certain low absorption window in the MIR and FIR, and the optical dispersion (or refractive indices) for some may need to be further characterized.
(1) Acetonitrile
See "Schafer SA et al., Mechanism of Biliary Stone Fragmentation Using the Ho:YAG Laser, IEEE Trans Biomed Eng, vol 41, no 3, 1994."
(2) Glycerol, 1,3-Butylene glycol, trimethylolpropane, Topicare(TM)
See "Viator JA, et al., Spectra from 2.5-15 um of tissue phantom materials, optical clearing agents and ex vivo human skin: implications for depth profiling of human skin, Phys Med Biol, 48 (2003) N15-N24."
Best of luck,
Kin
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I have two questions.
1) I have a molecule H2N-R-NH2, and I want to react one end using amine coupling reaction to attach SH as the terminal group. That is to day, the final structure is H2N-R-(linker, preferably alkyl chains)-SH. Does anyone know what is the selectivity (one-end functionalization or two-end functionalization) for amine coupling reaction? And is it to purify?
2) I have NC-R-CN, and I want to attach one end to get SH as the terminal group, i.e. NC-R-(linker)-SH. What chemistry is feasible?
Any recommendation on the literature is more than welcome.
Hello Juan,
is it important for you that specific NH2 reacts? or any of two? is your molecule symmetrical? If you work with 1 equiv. of diamine, there is a good chance to get mono-fictionalized product, which would also be possible to purify. For example, in the paper below:
Question
I want to know how I can find a specific structure of metal organic frameworks?
I need a molecular structure of Ag-BTC MOF.
How can I get it?
Can anyone help me on this?
A MOF is not a molecule, so you can't get a "molecular structure", but I understand you meant the crystal structure of that MOF. Of course single crystal (but also powder) diffraction may return you the structure.
A AgBTC MOF does not exist (apparently), whereas its Cu analogous is very well known (HKUST-1). Thus, Ag may be isomorphous with Cu (in this case a powder XRD would b enough) or not. If by chance someone has already prepared and measured it, then it would be listed in databases like Cambridge or others (and the cif file would be freely available).
Anyway, XRD is not the only technique to determine crystal structures. Other diffraction techniques are neutrons or electrons (here stability may be an issue). Or otherwise solid state NMR (here complicated by the magnetism).
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Hello Respected Seniors!
I want to collect samples from the Acid Mine drainage environment to determines the microbial community in that sample. So how we can collect the sample that the chemistry and biology of the sample are not disturb and we can get a significant result.
Hope that i will get a positive response.
Thank you so much.
Whether you are a student or a researcher, this might be of some interest to you. Not as an answer to your question, but as a source of ideas to consider.
Good luck.
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Hi everyone,
I'd like to verify if my solid phase extraction cartridge is saturated after i tried to purify a serum sample potentially containing drugs?
Thank you
Prepare a test sample by spiking a similar sample matrix (serum or plasma). Apply the sample to the SPE and fraction collect the flow-through. Continue past your usual sample volume X10. Treat the fractions as samples and reanalyze. I usually did a Protein Crash by adding 3X volume of acidified acetonitrile. Allow the protein crash samples to sit in ice and then centrifuge. Decant the supernatant and analyze for your molecule of interest. The result should identify the breakthrough fraction. You can also elute the SPE to see the maximum drug captured.
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Assuming that there may exist some decomposition products of chloroform ( stabilized with 0.75 wt% ethanol ) such as HCl, diethyl carbonate, ... what reactions can happen between calcium carbonate and chloroform?
Silver nitrate test does not show existence of any HCl in chloroform (at least by naked eye)!
Dear Friend,
Generally, the reaction of calcium carbonate with chloroform to form calcium hypochlorite is NOT affordable. In contrast the reverse reaction is likely to happen:
2Ca(ClO)2 + 2CO2 → 2CaCO3 + 2Cl2 + O2
In order to prevent any side reaction during the executing of your procedure I suggest to distill the chloroform and to use it freshly after distillation. Alternatively you can use distilled DCM since this compound is relatively much more stable than CHCl3. The reaction with DCM is expected to have less side reactions. Lead in the indicated concentrations is expected NOT to have any effect on the desired reaction.
P.S. It is advisable to treat the chloroform to be used in the reaction with sodium carbonate or sodium bicarbonate to neutralize any HCl present, and then to distill the chloroform and to use it freshly.
Rafik
Question
In the Lupine industry when lupin beans are detoxificated, lupanine goes to the wastewater. There is market for Lupanine and Spartein. But instead of extract they dispose of the brackish water in the sewers.
Low content of lupanine in beans and large volumes of waste water:
Question
hi Experts
I want to estimate and differentiate the different forms of potassium such as potassium chloride, potassium sulfate and potassium carbonate in the plant ash samples. Please suggest me the best methods and how could i achieve my goal.
Please have a look at enclosed PDF...
Question
Dear Friends,
I am working on a R&D project about increasing alkaloid content of Papaver sp. in in vitro conditions. My project manager asks me to isolate codeine from total alkaloids extracts from Papaver culture. Since I have no opinion about the procedure I checked online procedures and only find out cold water extraction way which is not suitable. I have to isolate the final product as pure as possible. Do you have any suggestions about it?
Hello Deniz,
I am working on alkaloids, but haven't worked on codeine specifically, I'm not familiar with it. However, I can give you afew suggestions.
- Cold extraction may work and still give you alkaloids
-Since alkaloids are non-polar, use non-polar solvents to extract. May consider 100% or gradients of the following, n-Hexane and DCM, or gradients of the two with ethyl acetate.
-Purify your fractions and isolate on HPLC
-Next step has two options depending on the availability of your resources:
- Either use a pure codeine if you have it as standard on HPLC or TLC and check which of your purified isolates match with the curve areas or RF of the standard codeine,
- Or, you can check these (Area under curve or RFs) online for pure codeine and compare with your fractions'.
- The one that matches is it. The tricky part is on the isolation, be very patient and sure on this stage.
All the best
Question
Hello,
I am trying to make a pH controller with Arduino using a solenoid valve. I want to be able to open my valve for a certain amount of time and lower the pH by X amount in a bucket. I am using phosphoric acid. My first question:
Let's say the pH is 8 and I want to reduce it to 7:
0) If the pH is 8 in the bucket this means a concentration of 10-8M?
1) How do I know which acid dissociation constant pKa to use 2.16 or 7.2 or 12.32 (7.2 because it's closest to my target pH?)
2) Next how to I use the HH equation pH = pKa + log ([H2PO4-]/[H3PO4]) ?
3) Lastly how to I account for volume in the bucket I'm trying to change the pH of ?
EXTRA:
4) Any idea how to account for flow rate out of the valve?
Thank you so much!!
0) The [H3O+] is 10^-8 M
1) + 2) This is not a buffer solution. The equilibrium pH is driven by the dissociation of the acid. Chapters on acid/base dissociation reactions from an undergraduate general chemistry textbook have details of how to handle this type of problem.
3) + 4) Do a mass balance on the system to obtain \rho (dm/dt) = dV/dt = \rho mf_in = Vf_in where mass change or volume change is density times mass flow rate in or just volume flow rate in.
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I want to know if there is a time or duration that is expected for AOC to change and cause bio-film development on membranes. This question is also applicable to pipelines for water distribution. Although the conditions for these two scenarios may differ due to several factors like material properties (membrane and pipes) and surrounding chemistry
AOC means Assimilable Organic Carbon
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When you create pectin from orange peels, lemon juice is added to neutralize the pH and also to neutralize the negative charges in the pectin. How come strands of Pectin contains negative charges? Will adding lemon juice to the orange peels neutralize the negative charges? Also, they use lemon juice in jams, when creating pectin.
Hello Luke,
Pectin is heteropolysaccharide, which contain charged sugar units, so-called uronic acids, usually galacturonic acid (GalA). Uronic acids have carboxylic group at C6 and thus negatively charged (anionic units). Native GalA is methylesterified in high degree (up to 80% depend on pectin source, i.e. apple, orange peels etc). During alkaline or acid hydrolysis of methyl ester groups in uronic acids we can create even more charged groups from native pectin!
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After synthesizing polymer-drug conjugate via a carbodiimide chemistry, is there any other way to confirm the conjugation between the polymer and the drug apart from NMR, FTIR and UV-vis? Can LC-QTOF plays a part in the conjugation confirmation?
Thank you very much.
You can try, but to get it standardized with your complex would be cumbersome.
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Dear All,
I have a pH electrode of BNC probe type ,which will give the output as mV .Can any one help me to convert sensor mV values into respective pH values .
Any suggestions /help is highly appreciated .
1. Choose two buffers, let say pH1 = 7.00 and pH2 = 4.00 and measure the corresponding E1 and E2 (in mV).
2. For a sample with pHx, you measure Ex.
3. Calculate pHx = pH1 + (Ex – E1)(pH2 – pH1)/(E2-E1)
Important notes:
- all buffers and samples must be measured at the same temperature
- use a stabilisation time of about 1 minute for the electrode response
- the instrument must have a very high impedance (500 Gohm, not used in common voltmeters; use a pH/mV-meter in "mV" mode to test the equation)
- use a 3rd known buffer as sample (e.g., pH= 9.00 or 10.00) to very if the sensor response is linear).
- at pH=7.00 , the common measured E is not zero; in the given equation, (Ex – E1) is the correction for this asymmetry
- in the equation, (pH2 – pH1)/(E2-E1) is the electrode slope.
Question
Hello,
I am trying to use microwave irradiation to synthesis a schiff base using salicyladehyde and phenylamine. Do i need to use a metal like CuCl2 to coordinate the reaction?
The method can be used without this material
Question
I developed a device for cutting the TLC plates. This is my new invention and this design is registered. I wish to commercialize this product.
Please let me know if it is useful for daily chemistry purpose.
Actual Background of invention:
We use scale and paper cutter to cut TLC Plates . Many people cut their hands while doing it,? moreover TLCs are not smooth and it is a time talking process (marking, tracing and cutting etc).?
To overcome these problems, I invented a TLC cutting device which has following features...?
1. It is very easy to use and almost safe to use.?
2. It is very cheap.?
3.? It can be used by any person without any training. Very user friendly.?
4. One can cut various sizes of TLC plates according to the needs.?
5. Ideal for normal chemistry reaction monitoring but can also be used for cutting HPTLC plates.?
6. Can be used for cutting glass TLC plates with suitable glass cutter.?
7. No marking is needed to cut the TLC plates as it is pre-calibrated.?
8. Occupy? same space as that of TLC Plate.?
9. One can see the TLC plate while cutting with transparent version.?
10. Made up of hard and transparent sturdy material so ling lasting .?
11. Comes with variety of materials and can be drafted according to the needs of clients. Some of the versions can be. colour printed.
12. Already tested with my colleagues and it is working fine.
Hope you find it interesting, please let me know if you are interested.
Warm Regards?
Dr Omprakash
Question
How did power came to exist? Is a natural thing? A human phenomena? Is it in chemistry and physics? Is it in atoms? How does it emerge?
The focus is on power structures and relations.
What a cool question... I think the definition for power will change with each of the scenarios that you mentioned. When we talk about humans, power is a very meta term that comes with all sorts of connotations. I think you might be asking, do other animals exert power over one another? I think that if we redefine "power" as dominance, then yes, many social animals clearly have social hierarchies. The first thing that comes to mind is macaques which have really interesting breeding rituals based on which female is dominant. The power is the privilege that certain individuals have based on who their parents are, in this case. Then of course there is power in strength. Because all animals are seeking to reproduce, in many instances the "stronger" "faster" "healthier" animals will be more successful and in that sense there will be competition in many organisms for the best to win. It is part of the evolutionary process of passing on genetic information. What about at the cellular level? I have heard a quote before that we are nothing but servants to our microbes. This could mean that everything we eat is really just serving as energy for the microbes and cells inside us to continue to produce energy, divide, and live. The power that you are talking about is now just becoming the "spark" of life. Is it the same for atoms? Well atoms aren't alive and so then we are really just talking about electrons themselves and all of the forces involved in making atoms do what they do. If one atom is more electronegative it will have the "power" to steal electrons from another atom. Is power then the same? I think that the idea is broad enough that we can easily substitute it for the other words I just mentioned (dominance, strength, life, energy) but do we get the spark of life because of the flow of energy? Do we get competition and dominance just because of life, and the need to keep our genes alive? Or is there some god-like power that is making all of these things happen? I dunno.
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How does this reaction happen that makes the mustard move around in certain path, is there a pattern for this?
Thank you sir! Sounds right to me.
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I want to ask if determining the seed oil content using gravimetric means such as done in the paper below is appropriate.
There were no chemicals used.
I could not find any other literature supporting this method.
Thank you very much.
Dear Renerio
Hughes, M. (1969), Determination of moisture and oil in the seed of winter rape (Brassica napus) II.-Comparison of extraction methods for the estimation of oil. J. Sci. Food Agric., 20: 745–747. doi:10.1002/jsfa.2740201211
Question
Some special drugs might be deformed and deactived next to high temperature so it cause many damages for their Productive factory
It is best to follow the manufacturers' instructions concerning temperature controls for certain drugs. In addition some drugs require a cold chain to keep them safe, therefore using thermo-flasks is acceptable. The below links gives some information on encapsulation and hydrogels
ttps://www.tandfonline.com/doi/abs/10.1080/096374899101256
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What are important topics for research in the field of organic chemistry?
Continuous flow reaction systems.
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Its just clearly mentioned on the article below:
"The chemistry of minerals obtained from the combustion
of Jordanian oil shale" written by: A.Y. Al-Otoom et al.
The structure and the strength of organic compound adsorption on mineral surfaces are of interest for a number of industrial and environmental applications, oil recovery, CO2 storage and contamination remediation. Biomineralised calcite plays an essential role in the function of many organisms that control crystal growth with organic macromolecules.
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For example, total number of molecules of Mn, S and O in MnSO4. I only know the molar mass and the total mass I have to prepare. I do not know the number of moles or molarity.
Calculate he number of moles you have by taking the Mass / molar mass. if you have 1000 grams ; then 1,000 g / 151.001 g/mol = X g moles. Then multiply by Avogadros # = 6.022140857 × 10^23 molecules per g mole. The result is the # of molecules of MnSO4. And there is one molecule of Mn per each molecule of MnSO4, but only two O2 molecules per molecule of MnSO4.
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I have my ZnO nanoparticles and I have to check the zeta potential at various different pH range from 2-12. But usual chemistry of ZnONP tells that they might start dissolving below 5.5 pH or so. In such case how do I go about?
How to prepare sample for just normal zeta measurement and for various pH? Which solvent (I use deionized water as of now)? Concentration?
If i choose phosphate buffer at various pH does that help?
I am very new to this method I have never done this before so I have no clues. If someone can guide me through how to go about from sample preparation to interpretation.
Can DLS be measured with same sample preparation?
You cannot measure the zeta potential of a system (particles + environment) without taking into account the chemistry. As you indicate ZnO dissolves in acidic environments. Thus there is no concept of zeta potential in such situations. Take a look at: Guidance to improve the scientific value of zeta-potential measurements in nanoEHS Gregory V. Lowry et al Environ. Sci.: Nano, 2016, 3, 953 - 965
DOI: 10.1039/C6EN00136J
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Do calcium ions act as a transesterification catalyst or depolymerization catalyst for PET in PET/PC blend system?
Calcium ions (based on operating conditions) can act as catalyst in
transesterification reactions of PET/PC system. In a study by Al-Jabareen, A.,?Illescas, S.,?Maspoch and Santana O.O. (2010), titled "Effects of composition and transesterification catalysts on the physico-chemical and dynamic properties of PC/PET blends rich in PC", they report that degree of transesterification depends on the amount of PET and presence/type of catalyst. All blends without transesterification catalysts (Ca or Zn ions) exhibited a degree of transesterification that decreased by increasing the amount of PET in the blend.
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Ifosfamide is one of the most famous and useful drugs for cancer but its very important that you know this pharmaceutical compound has many harmful effects on sick people , one of which is bleeding that is very danger for them and it might be so unbearable .
For ifosfamide, the dose-limiting toxicity is cystitis, if mesna is not co-admministered. If mesna is co-administered, the dose-limiting toxicity is myelosuppression. When compared with a similar drug cyclophosphamide, ifosfamide tends to induce cystitis and neurotoxicity more often. To suppress these side effects, modification of ifosfamide molecular structure would need to alter its metabolism, so that active metabolite iphosphoramide mustard is produced without urotoxic acrolein and neurotoxic chloroacetaldehyde. That would be quite a challenge.
And concerning increased risk of bleeding, this is a consequence of chemotherapy-induced thrombocytopenia, and this side effect is associated with many anticancer drugs, so it is not limited specifically to ifosfamide. It was reported as most commonly associated with platinum and gemcitabine-based regimens.
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What is spiral modulated spin structure in ABO3 Perovskite (ferromagnetic material) ?
Please have a look of the attached files.
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I recently conducted a coffee-cup calorimetry experiment in which we attempted to measure if the dissolution of inorganic crystals such as LiCl, NaCl, and SrCl were endothermic or exothermic based on a change in temperature over time plot, including measure the enthapy of solutions, but I'm not sure how to do that.
Methods:
We measured 7.9204 grams of SrCl2, 4.2143 grams of LiCl, and 2.9290 grams of NaCl and decanted these into separate coffee cups filled with 50 mL of deionized of water. (These were about 1 - 2 mole/liter solutions.). A temperature probe measured the temperature change over 600 seconds, recording a measurement twice a second. I've only displayed about 140 seconds of the measurement, because the temperature was just continually oscillating 0.1 degree Celsius after that point as it reached equilibrium.
We made plots for each of the chemicals, where an increasing curve shows an exothermic reaction, and an endothermic reaction displays a decreasing curve. Over time, these solutions (Temperature ~ Time) curves should equalize to equilibrium.
Theoretically, we predicted we could determine if the enthalpy of solution like so ...
Enthalpy of solution = Lattice Enthalpy + (Hydration Enthalpy of cation + Hydration Enthalpy of Anion),
where the Lattice Enthalpy is a measure of the stability of the compound crystal which is at least a function of the charges of the cation and anion, as well as their size, and the structure of the crystal body centered cubic vs face centered cubic, and the hydration enthalpy is the energy it takes to dissolve the gaseous ions after breaking the crystal lattice.
Schematically, the Lattice Enthalpies ( Δ H):
LiCl(s) ----> Li+ (g) + Cl- (g); ΔH = 852 kJ / mole
NaCl(s) ----> Na+ (g) + Cl- (g); Δ H = 787 kJ / mole
SrCl2(s) ---> Sr2+ (g) + 2 Cl- (g); ΔH = 2153
Source:
These Lattice Enthalpies were obtained from Table 18B.4 of my textbook:
Physical Chemistry Thermodynamics, Structure and Change, 10th Edition, VOlume 1, by Peter Atkins & Julio de Paula
Then the Enthalpies of Hydration are these:
Li^(+) (g) ---> Li^(+) (aq); ΔH = -519 kJ / mole
Cl^(-1) (g) ----> Cl^(-1) (aq) ; ΔH = -381 kJ / mole
Na^(+) (g) -------> Na^(+) (aq); ΔH = -409 kJ / mole
Sr^(2+) (g) -------> Sr^(2+) (aq); ΔH = -1443 kJ / mole
Source of Enthalpies of Hydration (Tables 1 - 2):
The Enthalpies of Hydration that I've used are experimental.
Smith, Derek W. "Ionic hydration enthalpies." Journal of Chemical Education 54.9 (1977): 540.
Therefore, the enthalpy of solution for LiCl, NaCl, SrCl2 is this:
For LiCl,
ΔHsolution, LiCl = (852 kJ / mole) + [(-519 kJ / mole) + (-381 kJ / mole)] = -48 kJ / mole < 0, so this reaction should be exothermic and it is as predicted.
For NaCl,
ΔHsolution, NaCl = (787 kJ / mole) + [(-409 kJ / mole) + (-381 kJ / mole)] = -3 kJ / mole < 0, so this reaction should be exothermic.
I've been searching the web about this reaction and most sources say it's endothermic which I my graph shows, but my calculations do not show that. What?
Doing the same kind of mathematics, the Enthalpy of solution for SrCl2 is this:
ΔHsolution, SrCl2 = [2153 + (-1443 - 2 * 381)](kJ / mole)
= -52 kJ / mole < 0, so this reaction should be exothermic.
BUT MY PLOT SHOWS that It's significantly endothermic!
What's going on? Is my mathematics faulty. Am I using too concentrated solutions? Is the SrCl2 that we are using impure or not really SrCl2? I suppose that's possible, but we didn't do any validation because this lab took quite some time. How is it possible that my experiments don't match theory mostly?
Thank you for you for your help.
Beside enthalpies, the entropy changes are also important. The salts are in crystal forms. They are highly ordered. When dissolves in water, they becomes hydrated ions, which are highly disordered. The entropy changes are significant.
Entropy,
An example on how to calculate the free energy change of the solvation of CaCl2,
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I'm going to make a suspension of Carbon black in order to mix it with another water base suspension and freeze-dry it. considering the point that carbon black does not mix with water properly I need to use another solvent. I tried DMAc but my sample melted during freeze-drying!!! I'm wondering what would be the best option?
Thanks
Dear Rassoul,
There are relatively few organic solvents that will freeze dry well - DiMethyl Acetamide is not one of them! It may be used for inks, but not freeze drying. Things like tert butanol, water, 1,4-dioxane, cyclohexane freeze dry well. DMSO can be used, but the risk here is having a suitable system for working with agressive organic solvents is the challenge (this is also true for DMAc.) as most dryers are made for water ...
To disperse the carbon black you will need a whetting agent in there, and you need to generate some viscosity in the mix to help it disperse well using a high sheer mixer. It is unlikely from my ancient knowledge of whetting agents (I'm not up to date) that these will not evaporate but will remain behind in the carbon black. Typically carbon black is dispersed into oils, not things that freeze dry well.
Do you really need to freeze dry? Is this the correct process?
Kind regards
Rob
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By looking at the structure of both molecules, I see that both molecules have at least two non-conjugated sigma bonds, making conductivity due to resonance seemingly impossible. I read from this paper " " that the conductivity of polystyrene is about 6.7*10^-14 S/m and polypropylene should have a conductivity somewhere between 10^-18 and 10^-17 S/m.
Some things I didn't consider is the density and porosity of the materials and possibly inter-molecular effects.
Agreeing in part with both colleagues I agree that:
- DC conductivity is determined by the charge carrier concentration and mobility
- the charge carriers can be intrinsic (coming from the polymer itself) or extrinsic (from impurities, catalyst residues, additives, antioxidant etc.), or can be injected from the electrodes (so-called ohmic contacts) or generated by external factors, such as irradiation. It is not always obvious to distunguish between these types of charge carriers
- the charge carriers can be electrons, holes or ions
- the charge carriers can be trapped in shallow and deep traps (from shallow traps they can beremoved by thermal activation)
- it is practically impossible to measure the equilibrium conductivity of PS or PP at room temeperture, you will observe a continuously decreasing current, and the final value may depend on the exactness of your zero detection.
Therefore the conductivity of these insulating polymers may depend on several factors:
- purity (additivation level, possible surface oxidation which may generate displacement current which appears together with the ohmic component)
- thermal treatment (recrystallization in PP and possible pyhsical aging in PS)
- quality and material of the electrode, method of electrode aplication
- voltage level (space charge limited currents, Poole-Frenkel effect and so on)
Therefor if you want really to compare these materials you could do the following:
- theoretically you can perform band sructure calculation on linear chains and compare the bandgap etc. perhaps you may imporve your calculations by taing into account local defects (local states in the forbidden gap). These calculations, however, cannot be checked easily experimentally (maybe by photoelctron spectroscopy)
- experimentally you may prepare high purity thin films (e.g. by removing the additives by dissolution and precipitation) of both polymers, sputter gold electode on both sides and (using guard ring!) you may compare the two polymers at identical film thickness at various levels of voltage and at various temperatures or at various levels of extrinsic doping and extrapolate back the behavior to low voltage and room temperature. Then you will have an approximately (!) exact picture of all processes. Then it is meaningful to compare the values.
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jcr based impact factor not the other one.
I am looking for JCR journals not only SJR. Dr. Rajkumar S Yadav . Your link is not of my interest. Thanks
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What are the basic mechanisms or processes that occur polarization in dielectrics?
I recommend the answer by K. Sreenvias
since the subject is almost prehistoric
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what are the basic differences between 1) Electronic polarization 2) Ionic or atomic polarization 3) dipolar polarization 4) Interfacial polarization?
I would suggest you to begin to read an old, but still excellent book:
A shorter, but useful text:
Regarding mechanisms of polarization:
For a more complete introduction to dielectric relaxation spectroscopy:
Believe me: it is much more useful to read a full chapter than to look for shortcuts and short answers
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how to determine indirect band gap using UV-VIS-NIR Spectroscopy ?
If the material does have a well defined bandgap, tauc plot would be incorrect. If the material is highly disordered, it will not have a well defined bandgap. Tauc plot can give you an estimate, but you could use other methods as well, since it is not well defined. There were multiple discussions in the past on this topic.
For an indirect bandgap material with a well defined excitonic bandgap, see the attached paper for measuring the bandgap of GaP (one of the best studied indirect bandgap semiconductors).
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how to draw Cole Cole plot Z vs Z' using impedence Analyzer with explanation ?
Enclosing one paper of ours on NiFe2O4 ceramics, in this we have used the some different shapes of cole-cole plots, and modeled them, and tried to correlate with he changes in the microsctructure, please go through it, you will be able to understand some explanations based on such analysis
K. Sreenivas
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Today, every educational field or domain contains several branches. You first choose one branch of your field to prepare your Master and Ph.D degrees. What is preferable system for you:
1- study the same branch at both Master and Ph.D degrees
or
2-study different branch at Ph.D degrees from Master degree
And, Why?
In my opinion, doing PhD in different field but the the idea of Master's is highly applied is good. Rising in academics is as going through ladder, slightly inclined so that the importance of each step is retained.
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How to increase the surface activity of low surface energy plastics?
How to make the surface of polyolefins Chemically active ?
Suggest me some practical ways to achieve it.
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Which techniques are currently being used to bond low surface energy plastics ?
How much bond strength can be obtained at most on plastics like LDPE, HDPE, PP?
Any rubber based Adhesive being used for such application?
Cyanoacrylates (one of them is Super Glue) are instant adhesives that have been used to bond low surface energy plastics for many years. Personally, I have tried to apply Super Glue on a broken polystyrene comb but it did not work.
I found that "an epoxy resin pre-polymer together with a diamine hardener" offered good adhesion for a variety of plastics.
However, the attached link talks about an adhesive "with 2 components" which is claimed to be effective. Needs trying, I think.
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I'm looking for the chemical reaction(s) involved in EROD assay to get a deeper look at its working principle. I've read abut the basic principle mentioned in number of papers, but i haven't come across one which tells about the chemistry of the assay in detail.
Also, which is the best database to find chemical reactions?
Hello Reema,
I guess, this helps in understanding the underlying biochemistry. This is just a speculation based on information.
1. CYP1A metabolizes xenobiotics.
2. EROD is one such enzyme which is induced by CYP1A while metabolizing xenobiotics.
3. 7-ethoxyresorufin is a fluorophore and substrate for EROD and a competitive inhibitor. Thus, if xenobitoics were high in media, CYP1A and EROD will be activated.
4. Hence conversion of 7-ethoxyresorufin by CYP1A-EROD system will be higher, and can be detected by change in fluorescence.
5. This assay can be considered to other catalase and SOD based assays.
I hope this helps.
Question
why is the color of PbSO4 in lead acid plates is black instead of normal white color for lead sulfate after the plates is discharged in lead acid battery ?
Dear Dr Valerii Kotok
Question
I'm interested in identifying examples of high-U and/or Th overgrowths of zircon of magmatic origin. Apart from metamictisation, what features/textures/chemistry are associated with this style of overgrowth?
Dear Gordon Webb,
The answer to your question "How common are U-Th-rich magmatic overgrowths of zircon in granites and related rock types?" is that it is indeed very commom.
The answer to your questio "How common are U-Th-rich magmatic overgrowths of zircon in granites and related rock types?" is that it is very commom that radiometric dating in zircons (zoned) must take in account every zone individually.
Since every overgrowth means that growth was interrupted and restarted again, it means that magmatic conditions changed (P, T and/or also chemistry). So, U and Th available was maybe different at any restart.
Magma mixing certainly changes magma final composition but magma mingling normally keep both magmas previous compositions and so it may induce new zircon overgrowth but with the same previous zircon composition.
Rapakivi and anti-rapakavi are feldspars textures largely related to magma mixing but some say it can also simply be self magma composition change while the minerals remove one constituent and enrichs in another (Na, K, Ca exchange).
It is very plausible that while parts of two magmas mix while at other parts where P and T conditions might be different they do not mix but only mingle.
I myself mapped a granitic pluton in which there were not only mixing and mingling between the two original members but also the mixed resultant hybrid magma mingling with its both previous magmas.
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First run of generating the polythionics APPEARED to work, got a turbid white solution with smell of sulfur but 304SS coupon did not crack. I'm looking for particular details about the reagent or setup that will lead to successful test on sensitized coupon of 304.
So, the original 1888 text says the H2S bubbling needs to be repeated daily for about 2 weeks. afterwhich, the temp is brought to room temp and the sulfurous odor returns, and H2S is bubbled again until the sulfur dioxide smell goes away. ASTM says you "may" have to repeat the H2S bubbling, original text says you will repeat for an extended period.
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I am working on sensor to detect lpg cylinder gases that does not work on electricity
This appears to be a statement, not a question. Please rephrase.
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What can be the best alternative for EDC, DMAP as catalyst for carboxylates? I want to skip DMAP actually.
There's an odd esterification method involving CBr4 that's fairly selective, but might work, depending on the structures of your substrates:
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Hi Dear All,
Boronic acids in general form complexes with cis 1,2 or cis 1,3 diols etc. If we want to protect the boronic while attaching it to any polyesters with multi hydroxyl groups. Could somebody give a nice idea to do that?
Kind Regards
Hello Rashid, here is a really good paper on the stability of boronic esters with various diol ligands and the rates of transesterification from one diol ligand to another.
The paper is on research gate and sciencdirect.
In general mixing a boronic esters and a diol in pentane for several hours, removing the water layer that forms, reducing the solvent volume and passing the concentrated reaction solution through a plug of silica gel with DCM as the eluent is a very effective way of esterefying and purifying a boronic ester. This is the method we often use in our lab. You can find the actual procedure in the SI of the Science paper on my researchgate profile. Here is the link to the paper http://science.sciencemag.org/content/351/6268/70
If you don't have access to Science Journal just let me know and I can upload the SI to my profile. Another common method that is used involves mixing boronic acids and diols in dichloromethane for several hours with a desiccants such as 4 angstrom molecular sieves (the method used in the first paper I mentioned).
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Hi All,
Could some one suggest an easy and efficient way to protect phenyl boronic acid with ethylene glycol?
Kind Regards
I am trying to protect two OH with Boron, through its condensation with ethylene glycol. this picture with give you an idea.
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How to select the active moiety in any aqueous extract and the chemistry of it?
Compare results of repeatedly cited literature to pre-screen candidate active compounds from your extract. Then, you can do separation techniques such as chromatography ,i.e. HPLC. However, purification will highly depend on your extraction protocol. For the chemistry of the compound, you can perform NMR spectroscopy.
Best,
Arizaldo
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Dear all,
I need good and up to date resources to find out the applications of nanotechnology at industry.
Thanks
a lot of the above will depend heavily what industry you look at as there are basically unlimited application examples, and no single source can cover metallurgy, semiconductor industry, building industry, medicine, pharmaceuticals etc.
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Metal oxides can be functionalized easily with any matter but why it is not possible to functionalize metal sulfides with materials such as for example their fictionalization with an Aerogel?
important question for me, I am following
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I want to conjugate streptavidin with some different peptides to make a target for biotinylated antibody. Need a protocol to do this.
Humana Press has published a couple of guidebooks with great recipes for peptide conjugation: The Protein Protocols Handbook, and Methods in Molecular Biology (especially Vol 36: Peptide Analysis Protocols).
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I have about 2000 of proteins ligands from Protein Data Bank and a lot of their characteristics like full name, molecular formula, SMILES, etc. I would like to classify them in several broad groups according to their chemical features. Is there any database with such data?
Thank you!
Hi, Kirill! you can try fingerprints based clustering, e.g. RDkit for python can do this (http://www.rdkit.org/docs/Cookbook.html#clustering-molecules)
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MF would lead to more hypertrophy, although there might be doubt. I am looking for views or literature that adresses the small boundaries between just the right amount of MF and too much. My hypothesis would be that MF is subjective and is not a good indicator for the state a muscle is in, in relation to training status and recovery.
Steele J, Endres A, Fisher J, Gentil P, Giessing J. A capacidade de prever as repeti??es para o fracasso momentaneo n?o é perfeitamente precisa, embora melhora com a experiência de treinamento de resistência. PeerJ 2017; 5: e4105. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5712461/pdf/peerj-05-4105.pdf
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I want to know the role of N-Nitrosobis(2-oxopropyl)amine reagent in the following amide formation from compound 11 to 12. Is there any specific reason for its use here?
If possible, please explain with mechanism as well.
I see your point and it might be a mistake. Benzotriazole-1-yloxy- tris-(dimethylamino)-phosphonium hexafluorophosphate (BOP; Castro’s reagent) is well known for the coupling of amines with carboxylates and has the same abbreviation BOP !
Good luck
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I am trying to determine the MIC of Silver Nitrate (AgNO3) against a number of bacterial strains using broth micro/macro dilutions method.
I prepared the AgNO3 in distilled water to a concentration of 1M. When I added this to my growth broth, it immediately forms a precipitate.
I initially used Tryptic soy broth and thought it was the salt content of the broth causing the precipitation, so I then tried Mueller-Hinton (MH) broth, and Mueller-Hinton-II (MH-II) broth (cation adjusted). Using my initially prepared AgNO3 solution, no precipitation occurred.
I then prepared a fresh stock of 1M AgNO3 solution in order to preform a MIC, but this solution formed precipitate upon addition to the MH broth.
The precipitate formed is white and heavy. This gives the impression it's AgCl, but with no NaCl in MH broths, I'm not sure how it could be forming.
Ideally, I need a broth that will not cause precipitation, or any additive I could use to prevent precipitation without having any adverse effects on the bacteria samples.
Any advice on this issue would be greatly appreciated!
We've used silver nitrate by diluting it in 28% w/v PEG 400, 26% w/v sorbitol to a maximum of 3% AgNO3 and used this for dilutions (up to 10-4) in MIC/MBC assays.
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The characteristic frequency of thermal motion is around 7E12 Hz at room temperature (300K), but from that information how can we conclude that the bonds are hard; they don't vibrate !!
Dear Roshan,
The bonds use the hopping energy and this is much higher than the thermal energy. Notice that one eV is equivalent to a thermal energy of 11604.5 K !!! Thus the phonons (accoustic or optical) don't interact practically with the bond electrons.
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Hi,
I would like to know the procedure of desorption for Supelco SPME C18 fibers used with LC application.
In my experiments if I desorbed them in MeOH there is a lot of carry over whereas when I desorb with a small magnetic stirring in MeOH, im getting more recovery.
Please suggest what is the best to present in an article.
Any suggestion or article link would be highly appreciated.
Thank's
Adsorption Chemical ; It is to be links between surface molecules of the metal (or any other material with high surface energy) and other material (gas or liquid) in contact with him.
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Hi all,
I looking for literature evidence for this phenomenon.
Apparently, RNA (I'm not sure if also DNA) is cleavaged in a non-enzymatic manner by iron.
I would need some theory to support this.
Do you know if this is mediated specifically by Fe2+, Fe3+ or both ion species?
Is this cleavage reaction enhanced in some chemical conditions ? (pH, polarity, ionic strength, etc.)
Which is the level of iron need to degrade RNA ? (micromolar, milimolar)
Only happens with RNA or also with DNA?
Guillermo
Here are two references:
> Lloyd DR, Phillips DH (1999) Oxidative DNA damage mediated by copper(II), iron(II) and nickel(II) Fenton reactions: evidence for site-specific mechanisms in the formation of double-strand breaks, 8-hydroxydeoxyguanosine and putative intrastrand cross-links. Mutation Research 424, 23-36.
> Mello-Filho AC, Meneghini R (1991) Iron is the intracellular metal involved in the production of DNA damage by oxygen radicals. Mutation Research 251, 109-113.
Peter
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I read in an article where I found the term plasma activated HCL , I was wondering how to achieve that?
Dear Syed Shajar Ali Imam
The Indirect air dielectric barrier discharge (DBD) can help you to get plasma activated HCl.
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Fosfomycin is a bacterial cell wall synthesis inhibitor which can't be grouped into conventional antibiotics i.e. penicillins, cephalosporins, macrolines, quinolones etc. Thus it might be the major effective functional group which one is responsible for exerting its bactericidal action. I want to know the group as I am working on that molecule.
Based on my little evaluation of the fosfomycin [(2R,3S)-3-methyloxiran-2-yl]phosphonic acid], the functional groups that may be responsible for its action will be the oxiran-2-yl instead of carboxylic group that normally present in PEP [2-phosphonooxyprop-2-enoic acid]. This shift the configuration from organic acid to organophosphoric acid.
I will also conduct further work on this approved drug.
Best regards,
Toluwase H. Fatoki
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This is the scenario:
1) Irrigation water with a composition of ferric nitrate [Fe(NO3)3], ammonium nitrate [NH4NO3], ammonium nitrite [NH4NO2], ammonium nitride [(NH4)3N] and humic acid (full of N). Alcalinity 150 mg/l, hardness 250 mg/l, salinity 0.6 g/L, electric conductivity 1.5 mS/cm, pH 8. 25oC.
2) Water Ozonization parameters: 3.5 L/min, 80% O2 richness, 65 g O3/m3. Invariable water volume 500 mL.
So...
What do you think it will ocurr?
Will all the nitrogen present in an irrigation water (in its organic or inorganic forms) become nitrate after ozonation of the water?
Will alcalinity or hardness change in any maner?
Will salinity or electric conductivity change?
Will the pH be important for that supposed change?
I'm looking for different and interesting opinions about it because I'm doing experiments on that subject, and reading many papers too, but I'm finding some exciting contradictions.
Juan de Dios
You don't mention the treatment target for the ozonation which determine how much ozone you would add. Do you ozonate to disinfect the water, remove the color or a specific chemical pollutant?
If you ozonate to a level there you perform disinfection or decolorisation you will oxidize nitrite to nitrate but not organic nitrogen and ammonia.
Alkalinity, hardness, salinity and electric conductivity doesn't change with ozonation. pH is very important for the ozonation process. Both required dose, products formed and reaction kinetics change drastically e.g. between pH 6 and 8.
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Chemistry
Thermodynamics
Usually, d is the full differential (infinitely small change) of some parameter, delta is its finite change, small delta can desribe the infinitely small variation of the some parameter, partial derivative shows the change of the value of some thermodynamic function at changing of one its parameter when this function depends on some parameters.
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Hi, in my chemistry course we talked about fluoride in toothpaste, what chemical reaction occurs when using it and why it is necessary (I'm talking about the metathesis of Ca5(PO4)3OH to Ca5(PO4)3F). One of the possible exam questions is if fluoride in drinking water or in toothpaste is more efficient. I know not everyone is pro fluoride in drinking water, but when you look at it purely chemical, what is more efficient? Google hasn't been able to help me.
Fluoride in drinking water is an essential nutrient for the health of bones and teeth, but it is harmful when the concentration exceeds the permissible limit. According to the World Health Organization, the maximum permissible limit of fluoride in drinking water is 1.5 mg/L.
A low content of ?uoride (<0.6 mg/L) causes dental carries, whereas ?uoride-rich water (>1.2 mg/L) can lead to dental ?uorosis, and excessively high concentration of ?uoride (F > 3.0 mg/L) may lead to skeletal ?uorosis.
Best wishes
Question
Why or why not?
In the broad interest of protection of environment, I feel we should support the divestment.
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Is it true that all the biodegradable plastics will dissolve in dichloromethane?
This could be helpful for you:
ASTM D5988 - 12 Standard Test Method for Determining Aerobic Biodegradation of Plastic Materials in Soil
Microbial Oxidative Degradation Analyzer (MODA) according to ISO 14855-2.
Best regards Vit
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I am a master degree student wanting to learn deeper about perovskite solar cells. My knowledge about chemistry is rather half-baked. Please let me know the necessary textbooks I could learn in order to understand the chemistry of perovskite.
Dear
Risdiandita
Very interesting question. Basic knowledge on stoichiometry, chemical reaction and skill (training) are very important for preparing any material. That are enough.
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How can I prepare a stable solution containing chitosan-caseinate sodium complex without precipitation?
Chitosan, a cationic polysaccharide, was heterogeneously deacetylated with a 47% sodium hydroxide solution and followed by a homogeneous reacetylation with acetic anhydrides to control the N-acetyl content of the chitosan having a similar molecular weight. The chitosans having different degrees of N-acetylation were complexed with sodium alginate, an anionic polysaccharide, and the formation behavior of polyelectrolyte complexes (PECs) was examined by the viscometry in various pH ranges. The maximum mixing ratio (Rmax) increased with a decrease in the degree of N-acetylation of the chitosan at the same pH, and with a decrease in pH at the same degree of N-acetylation.
The chitosan-caseinate complexes formed were stable and soluble in the pH range 4.8-6.0. In this pH range, the biopolymers had opposite charges. At higher concentrations of chitosan (0.15 wt%), the soluble complexes associated to form larger particles. DLS data showed that, between pH 4.8 and 6.0, the particles formed by the complexation of chitosan and caseinate had sizes between 250 and 350 nm and these nanoparticles were visualized using negative staining TEM. Above pH 6.0, the nanoparticles associated to form larger particles, causing phase separation. Addition of NaCl increased the particle size. The pH dependence of the zeta potential of the mixture solutions was appreciably different from that of the pure protein and pure chitosan solutions.
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Why or why not?
We have to be very careful before introduction of any GM food. It is directly against the way and direction of evolution. Our previous experience with BT brinjal and BT Cotton (not food) is very bad in India.
The yellow colored fruits and vegetables, egg yolk, liver of cord fish etc. are very good source of vitamin A. The Vit. A deficient poor people may be given those food item. Why they should be thrown in the risk zone ?
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Which topics/subjects do you think that everyone involved in science should know or master, and without it his progress will be flawed?
phantasy
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I am trying to prepare silica nanoparticles. I followed the literature as suggested that in all reagent in ethanol mixture added TEOS, in some other literature they added Ammonia solution to mixture of all other reagents. all reagents and concentrations and temperature are fix. which one is give best results of silica particles. if these two process has effect on size and shape, then why and how it effects. Please explain or share literature of particular discussion.
Answers are expected from experience researchers.
Thank you
Raj Kumar
Ammonia is added as a pH modifier/stabilizer. pH has a large influence on virtually every property associated with (aqueous) nanotechnology. In certain cases (e.g. Ag nanoparticles) the precursor to be reduced to the colloidal metal can be provided in the complexed form (the diammine in the case of Ag). Certain species will be soluble in low or high pH's and silica is soluble much above pH 12. The concentration of ammonia can be important too as well as the pH.
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Looking for some Suggestions / Advice - may be a debatable question
For a Researcher - Procuring Chemicals / Drugs always a burden since getting a Chemical / Peptide from In / Abroad in which one has to pay a lot of Tax,Shipments,Supplier commission.
suppose a chemical / peptide, costs $85 in abroad, if that has to be reached, one has to pay 160$ (85$+ shipping charges 30$ + Customs 25$+ middlemen 20$) Its almost double the price of chemical.
Most of the Research funds gets crunched by these situations.
Is it necessary to pay all these taxes, these can slow down the process of Research Especially in India.
This is unavoidable. Only way out to look for drug synthesized by Indian Industries. I believe options are limited but we are helpless.
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