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
I have a 200 mg/ml ampiciline solution, how much should i add to 300 ml of LB medium to get the final concentration of 40 ug/ml?? How much bacteria (in ml) should i add to 75 ml of medium to dilute the culture 50 times??
Hello everyone,
I have 5 Samsung 21700 - 50 E (NCM chemistry) cells. I want to do basic charge and discharge by connecting it in series. Does anyone know if there is a cell holder available online for single cells? Or how to connect these cells and make contact?
Thanks in advance
I need to get BrHPP for expanding Tgd cells, so if anyone knows about a biotec/chemistry company that has it commercially available I would appreciate the information.
Thanks!
Study of different types of high school chemistry teaching methods in California
Or Texas or other states
Hi every body,
I have tried to synthesis aliphatic isocyanates from their acylazide compounds based on Curtius rearrangement. Based on articles, the converting of acylazide to isocyanate must be done through a simple thermal treatment in toluene or benzene at 1-2 hours and via the evolution of nitrogen gas during reaction. However, I have repeated it many times and no isocyanate is formed after reaction. Could you please share your experience with me?
Unfortunately, I found no repeatible results from articles.
Thanks in advances
Good evening,
I am looking for methods according following topic:
Vegetable oil (raps) contaminated with hydrocarbons (e.g. motor oil) shall be purified and separated from hydrocarbons. (Usage for in-situ soil remediation)
Thank you all in advance, I am looking forward to your ideas and suggestions.
BR Paul
How is chemistry taught in schools in the United States?
A comparative study of high school chemistry education
Chemistry is frequently termed the "central science". It underlies the foundation of modern civilization (drugs, plastics, textiles, dyes, fertilizers etc.), but the public perception of chemistry and chemicals is often negative. What can we do to overcome public misunderstandings of chemistry?
Hello,
I would like to calculate the monomer molecular weight of cellulose acetate butyrate (cf. attached figure). The average molecular weight of the polymer is 30000 g/mol. However, the polymer bears different residues (Acetyl, Butyryl , and Hydroxyl groups) and the extent of labelling is given as mass fraction in the datasheet as:
12-15 wt. % Acetyl
36-40 wt. % Butyryl
I assume the (average) remaing 43.5 wt. % are hydroxyl groups? There is no more info on that.
How can I calculate the average molecular weight of one monomer?

My team and I are curently working on a project is focused on preventing microplastics and collecting plastic particles up to 2 * 2mm. Our biggest concern is harming sea life and destroying plankton. I hope if you could advise us in which direction to go in our research. Is there a possibility that the filter / mesh and microplastic can be transformed by a biochemical process into something that would not harm sealife?
My team and I are curently working on a project is focused on preventing microplastics and collecting plastic particles up to 2 * 2mm. Our biggest concern is harming sea life and destroying plankton. I hope if you could advise us in which direction to go in our research.
Is there a possibility that the filter / mesh and microplastic can be transformed by a biochemical process into something that would not harm sealife?
I am not sure if any one study on this topic. It has been observed in certain cases that success-full researchers have poor academic record. These are exceptions, I am interested to know any study on this topic. Please also cite examples that shows negative or positive examples. Ideally there should be high positive correlation, if it is not than why?
I mean if person got good grade/marks or rank at school/university level will be a grate scientist. For example if topper of JEE (top exam in India for getting admission in engineering college) join research, he/she will be best scientist in the world.
Hello,
I did a oxygen plasma surface treatment of a polydimethysiloxan surface. i coated it with two different materials and the bonding improved significantly with one of the materials.
the other material wasnt affected at all by the plasma treatment.
Now i want to draw conclussion about the polymer that are used in this materials. Which kind of polymer bond with a oxygen plasma treated pdms surface?
I think the material with the improved bonding is a silane-terminated polymer, but i am not sure about it.
Please let me know if you got some knowledge about this topic or any hints for me
Thank you
If I dissolve 35 g of NaCl in 100 ml, what will be the approximate specific gravity?.
Is it 1.35? or is there some trick?
I read that saturated NaCl soltion has specific gravity of 1.2.
Also I read 35.9 g of NaCl can dissolve in 100 ml of water (which will approximately give 135.9 g/100 ml solution.
it means 1359 g/L, which means 1.359 specific gravity.
I am bit confused. (did I do a mistake?).
please help me.
Hello all
Thanks for answering my previous questions. I am making perovskite LED and intend to use PEIE on zinc oxide layer as ETL. But I am not sure what version of PEIE to us. There is the one with Mw 70000 g/mol which is not available , but the one with Mw = 110000 is available. But I am reluctant as I do not what effect high molecular weight will have on the performance of LED. I anyone could guide me with this it would be helpful.
Thanks
Jitesh
Chemical engineers translate processes developed in the lab into practical applications for the commercial production of products and then work to maintain and improve those processes. They rely on the main foundations of engineering: math, physics, and chemistry (though biology is playing an increasing role). The main role of chemical engineers is to design and troubleshoot processes for the production of chemicals, fuels, foods, pharmaceuticals, and biologicals, just to name a few. Chemical engineers work in almost every industry and affect the production of almost every article manufactured on an industrial scale. They are most often employed by large-scale manufacturing plants to maximize productivity and product quality while minimizing costs.
Students (max of 5 student per group) are asked to write a 10-15 page essay (inclusive picture)
emphasizing the the critical contribution of chemical engineering to a pathway to sustainability
Submit your article to the google classroom in pdf format
If I have a solution that has an unknown amount of NaOh and NaCl, could I determine both concentrations using an electrical conductivity probe and a pH probe together? Is this possible? I can't figure out how to separate the NaOh and NaCl out during the concentration calculations from conductivity.
I am doing my thesis and would like to extract triglycerides from Olives or Olive Oil. I will be analysing the amount of triglycerides that are present in the olives or Olive Oil I will be testing. I would also like to extract them so that I may convert them to Fatty Acid Methyl Esters for biofuel. Does anyone know and/or have any papers that I may use? Thank you.
If you were/are researching in field of transport in porous media, Let's share some information about current researches in field of "Transport in Porous Media" and its applications such as CO2 storage or in chemistry engineering.
What has been/did you investigated?
What is going on right now?
And which areas in this field has remained untouched yet?
looking forward to receiving your comments.
In our research in scientific papers and handbooks, we probably face two different scientific chemistry terms, which apparently are the same, however they are totally different.
These two chemical terms are "Absorption" and "Adsorption". What do you think ? Are they the same? If your response is negative, so what are the differences between these two chemistry terms ?
Thanks a lot for your answers.
I have one more question: after synthesizing ZnO nanoparticles , I am not able to separate from the original solution (dispersion actually). The recipe is as follows:
1.5 mmol Zinc acetate dihydrate in 15 ml DMSO stirred at 30 degree celsius. then 2.8 mmol tetraethylammonium hydroxide pentahydrate (TMAH.5H20) in 5 ml ethanol is dropped in the solution. The solution is kept stirring 24h prior to the precipitation process. The ZnO nanoparticles were precipitated by ethyl acetate, and washed with ethyl acetate and ethanol for one more time. Finally, the obtained ZnO nanoparticles were dispersed in 8mL ethanol and filtered with 0.45 micron filter before use.
I have some major questions in this process:
1. How can I separate the ZnO NPs for washing? I tried centrifugation at 6000 rpm but i could not get rid of the solvents (DMSO and ethanol).
2. What is the volume of ethyl acetate to be dropped for the precipitates?
Please it would be great if anyone could help me resolve this issue.
Kindly suggest me some good papers regarding a comparative study on various organic solvents used as dispersion medium for graphite powder. The application is to make a graphite paste and used the slurry for coating on TCO using doctor blading deposition technique.
I am a young researcher studying the depolymerization of plastics. I still do not have great insights about how to identify great research.
I often read highly cited research in elite journals such as Nature or Science. There, I see that many chemical reactions are also reported with very few number of replications (a lot of times, just one!). How is it that this research becomes high impact of it is not sufficiently reproduced for a large number of samples?
Hello,
I have the feeling that everything in chemistry related to information and data in particular is very sharded and obscured. Are there any projects ensuring more transparency and openess of the data? I am getting quite lost to be honest and would wish for more standards and unity in the field.
Thanks,
Julian
Greetings.
During experiments and reading about MOFs, I found something that is strange to me.
For instance, in MIL-100/101, the secondary building units (SBUs) are [M3(μ3-O)(O2CR)6L3]n+/m−, while some reports claim that their as-synthesized MOFs are constructed by [M3(μ3-OH)(O2CR)6L3]n+/m−.
Both of these SBUs are 6-connected, topologically they are the same. But from the aspect of chemistry, O-center or OH-center makes a lot differences especially in the valances of related metal ions (for instance, Co2+ or Co3+, Fe2+ or Fe3+, etc.) and in the counter ions in pores/L sites (like dimethylammonium ions, coordinated fluoride ions).
I am wondering, is there any way that we could determine the actual form of this 'center' ?
Hello fellow chromatography experts. This is a subject for a fruitful discussion that everyone can benefit from. To make it helpful, I appreciate that you provide a reference to support your preference.
The topic is: When to use Linear fit for the calibration curve, and when to use a Quadratic fit? Is it analyte-dependable, which means the quadratic fit is reserved for a group of analytes sharing a specific chemistry for instance? Or is it a technique-dependable, which means if the technique is Gas Chromatography then a linear fit should be used, and so on? Or is it a column-dependable, you know the drill!
The second part of this discussion should be about the proper weighing power when making the fit. Again, is the weighing power is dependable on any factor I mentioned earlier or did not mention at all, or is it just a user preference?
Let me add to these two topics another one. If you calibrate your instrument with a five-point calibration curve, and after a number of injections you decide to inject a control sample to check your instrument's response. What percent deviation from the initial calibration you would accept before recalibrating?
Let's discuss these topics and make our discussion a good reference for beginners in the chromatography field.
according to you what are Hot problems currentlyworld is facing? And what solutions you would suggest to solve them?
Dear Colleagues,
I’m pleased to inform you that open access journal /Catalysts/ (ISSN 2073-4344, Impact Factor: 3.444) is planning to publish a Special Issue on the topic of "Trends in Catalytic Advanced Oxidation Processes". The submission deadline is 30 March 2020.
This Special Issue is dedicated to novel achievements in the field of catalytic advanced oxidation processes. The contributions should be related to the listed topics:
· Catalytic processes in water and wastewater treatment
· Developments in Fenton-like AOPs
· Activation of Persulfates for AOPs
· Formation of sulfate radicals
· Catalytic cavitation-based AOPs (hydrodynamic cavitation and acoustic cavitation)
· Sonocatalysts
· Catalytic ozonation
· Photocatalysts—including visible light and UV applications
· Catalytic wet air oxidation (CWAO)
· Catalytic–electrochemical AOPs
· Carbon catalysts for AOPs
· Nanocatalysts
· Risk of by-product formation during water and wastewater treatment
· Developments in process control of catalytic AOPs (analytical methods, chromatographic, and spectroscopic techniques)
· Methods of catalysts characterization
· Post-process assessment of effluents toxicity
· Application of nanobubbles in AOPs
· Economic analysis of catalytic AOPs application and catalysts life cycle assessment (LCO)
· Industrial catalytic wastewater treatment
· Modelling and optimization of catalytic processes
· Green chemistry aspects in catalytic water and wastewater treatment
Detailed information regarding this issue, please follow the link below to the Special Issue website at: https://www.mdpi.com/journal/catalysts/special_issues/catalytic_aop
By publishing with Catalysts, you will take advantage of the following attributes:
*Fast Publication*:
First decision provided to authors approximately 13.4 days after submission; acceptance to publication is undertaken in 5.5 days (median values for papers published in this journal in the second half of 2018).
The papers will be processed immediately upon receipt. A Special Issue (SI) is not an issue of the journal. It is a collection of articles on a common topic. These articles are published in the regular issues of the journal when they are accepted (no delay) but additionally labelled with the Special Issue name (including a link). A single click on the link will organize all the articles on the Special Issue webpage.
*High Impact*:
According to Web of Science data, the impact factor for Catalysts 2018 was 3.444. The five-year impact factor was 3.808. Catalysts now ranks in Q2 of the "Chemical, Physical" category.
According to Scopus data, the CiteScore for Catalysts 2018 was 3.85, which ranks it in Q1 of the “Chemistry, Physical and Theoretical Chemistry” category, and Q2 of the “Chemical Engineering, Catalysis” category.
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In order to plan for the whole paper project, I appreciate you could inform me within three weeks as to whether you would be willing to contribute. I also encourage you to send a short abstract to me (grzegorz.boczkaj@pg.edu.pl) or to Caroline Zhan (caroline.zhan@mdpi.com) in advance.
Sincerely hope this invitation will receive your favorable consideration.
Best regards,
Guest Editor
Prof. Grzegorz Boczkaj, PhD. Sc. Eng. Assoc. Prof.
Email: grzegorz.boczkaj@pg.edu.pl
Department of Process Engineering and Chemical Technology, Faculty of
Chemistry, Gdansk University of Technology, 80-233 Gdansk, Poland
Caroline Zhan
Assistant Editor
Email: caroline.zhan@mdpi.com
Catalysts (IF 3.444, http://www.mdpi.com/journal/catalysts)
Polyhalite is a multi-nutrient source, its application assume to be changes the soil biology and nutrients chemistry on long term basis
Hey scientists,
I am just wondering what functional groups can be added to a hydrophobic molecule to make it water soluble at basic pH?
As a case study, let's just consider ethyl benzene as the scaffold. Not very soluble in water.
How can we make it soluble at basic pH? But extending functional groups to the carbon chain.
I know for instance, that you can have ethyl benzene. It can be made soluble at acidic pH by adding an ammonium chloride group. If you could convert ethyl benzene to phenethylamine by adding an amino group to the carbon chain then you got ethyl benzene. Still not very soluble. But if you react phenethylamine with HCl then you group phenethylamine-HCl or phenethylammonium chloride which is very water soluble at pH less than or equal to 7.
If you had ethyl benzene, what functional group could you add to make it soluble at basic pH?
I think that if ethyl benzene if we added a COOH group to the carbon chain we would have 3-Phenylpropanoic acid . If we reacted NaOH with that we would have 3-Phenylpropanoate Sodium Salt which I predict would be soluble at basic pH.
Is that correct? What other functional groups could I add to ethyl benzene's carbon chain to make the molecule water soluble at basic pH. Are there any functional groups that I could add to the carbon chain of ethylamine to make the molecule water soluble at basic pH and also positively charged? Like for example phenethylamine-HCl is positively charged but only soluble at acidic pH.

In experimental, the bond energy per atom rises quadratically with the number of bonds then why in simulations this bond energy per atom rises linearly with the number of bonds per atoms?
dear friends, what is the most suitable iron complex to work with photo-Fenton without needing to stabilize the pH between 2.5 and 3?
I would like to work with the reaction at a pH between 4.5 and 6, would it be possible using some iron complex? like for example ferrioxalate?
Could anyone suggest me some good papers which involves the coating or mixing of MXenes with conductive polymers such as PEDOT or PANI or any other conductive polymer for that matter.
Suppose you have a mixture mostly comprised of saturated fatty acids of carbon chain length C10-C20. Is there a process to convert them to unsaturated fatty acids?
The opposite process is well known. Margarine is produced via hydrogenation of unsaturated fatty acids to obtain saturated fatty acids. Is there something like a dehydrogenation process for saturated fatty acids?
If this process is feasible, could it be done in a targeted manner to yield mostly Omega-3 and Omega-6 fatty acids?
Hi Research Gate,
A little background first: I'm a physicist, and I've done most of my work studying how chemical reactions move when they're pushed around by fluid flows. The trouble with this is I'm very limited because I don't know a lot of chemistry. I understand chemistry when I see it, but need to have a reaction identified before I can start trying to understand it. What this means is I have done most of my research on a single chemical reaction (The Belousov-Zhabotinsky reaction). The interesting phenomena around the BZ reaction, weren't my focus though, it just happened to be a reaction I knew how to make and that I could easily watch with a camera. However, I now want to go a little deeper into what's happening and the complex chemistry of BZ just gets in the way of understanding.
So I am asking you all if anyone has a suggestion for some interesting chemical reactions. For now I'm especially looking for reactions that 1) occur in the aqueous or liquid phase (so they can flow but are easy to contain) 2) Will sit inert until activated (now ideally I'd like the reaction to be completely mixed but need a catalyst to start an autocatalytic reaction, but I'd also take reactions where nothing happens until the second ingredient is added).
I'm also especially interested in reactions where it's easy to visually tell one state of reaction from another (say using an indicator dye). It would also be good if I could make the reaction from pretty standard chemistry supplies. Lastly I'd of course like reactions with practical import, say if the reaction makes something useful.
I know it's quite a list of things, but I'm hoping some helpful chemists (or even high school chemistry teachers really. As I said I'm not an expert on chemistry), are willing to pitch some suggestions.
If it's a reaction you study but don't want to deal with fluid dynamics on, great! I'm plenty willing to talk about what I'm trying to do.
~Thanks for reading, and hope you can help!
Thomas
I am following this recipe for PBABr synthesis. I added HBr (48 wt % in H2O) to Methanol and PBA solution at 0 degrees celsius. But after 2 hours of stirring I am not able to see precipitates. I have to evaporate the solution at 50 degrees celsius to obtain precpitates, I did that and still did not see any precipitates. Please help me with this. Thanks in advance!
Not another chemistry Nobel going to biologists!’ How many times have you heard that complaint? But is there really anything in it?
It’s sometimes said that the number of chemistry prizes awarded to work rooted in the life sciences – at least nine of the prizes since 2000 – simply shows how broad chemistry is: at the molecular scale, biology is chemistry. But does that argument stack up? A historian of chemistry and a mathematical chemist argue in a new paper that, not only have the chemistry Nobels indeed become more biological in recent decades but also the prizes of that nature tend to reward work outside of the chemical mainstream, being much more closely tied to research in the life sciences itself. In effect, they say, the chemistry Nobels are being shared out between genuinely different disciplines.


I would like to know the different deposition techniques and the respective conditions and constraints to deposit or coat a layer of MXene (Ti3C2Tx) onto a TCO glass substrate.
There are many research in field of "Transport in Porous Media" which is applicable from CO2 storage to chemistry engineering.
I like to collect more information on
What is going on right now in researching in this field?
And which areas in this field has remained untouched yet?
I got a silicone substrate and I coat it with a conductive polymer.
But the conductive polymer doenst adhere very well, I did a crosscut test and the conductive polymer fully detached.
Which possibilities do I got to improve the adhesion?
Thank you.
Hello Good day i am a undergraduate student, please help me to have a topoc of my research proposal about organic chemisty. Thank you so much.
I've already checked solubility of sodium chloride (NaCl) in water(20℃).
According to the solubility data, 359 grams of sodium chloride should be dissolved in 1 L water.
so I put 245.2 grams of sodium chloride into 1 L water and let the mixture into the ultrasonic cleanser and shaking plate for minutes, but It doesn't dissolve well. I can even see that the powder is deposited.
I want to make a sodium chloride solution with a concentration of 245.3g/L.
Can you tell me what the problem is?
They've invited me to publish and to become a reviewer/editor.
I'm an intern in a big company which makes flexible polyurehane foam for the automotive sector and I'm working on sound absorption properties of PU foam. I'm not chemist so I'm trying to improve these properties only by modifying process parameters.
ANSYS or ABAQUS donot correlate materials chemistry wirh the observed or simulated mechanical properties. Is there a software that can do this structure to property correlation. ?
I'm working on counter electrode for DSSC application, i would like to know if the CoSe can be doped with a MXene like Ti3C2Tx.
Hi, everyone.
Our lab is going to use ISO 12966-2 and 12966-4 and there is one moment in sample preparation (rapid transmethylation method under alkali-catalysed conditions) that I can't understand. It is about the addition of saturated sodium chloride solution after transmethylation reaction. Maybe I'm not so good in chemistry to understand the purpose of this action. So, can anyone please help me to get it?
Considering the context of the COVID-19 pandemic that requires remote teaching activities. In the case of Chemical Education, which requires a high degree of abstraction and the use of visualizations can effectively contribute to the student's learning process, how does the teacher deal with the relationship of macro, micro and symbolic representations, in online teaching?
Is is possible to find out if a material can function as a cathode or anode by just looking at cyclic voltammetry.
For our research subject in high school, we are required to conduct a research that can be done at the safety of our homes. Does anyone have any suggestions on what kind of topics we can research on? Thank you!
Dear Chromatographers,
This method was developed on LC MS/MS. The quantifier for both analyte and internal standard have same product ion, will that have an impact on overall analysis. Any supporting article to read more about this would be very helpful.
Thanks
As you know, a time crystal shows oscillations with a period longer than the driving force. Is it possible to use this feature in molecular machine synthesis? Does this provide any advantages to molecular machines?
I got the idea from using filters and other filtration systems in previous research experiences, and also how recently... someone gave me a bunch of Monster Energy drinks but they aren't sugar free so it got me thinking how it would be possible to extract the sugar from the Energy Drinks mechanically.
Sugar molecules are 1nm in size
salt (NaCl) is .06nm in size and water molecules are .275nm in size.
Would this work as planned or is there something my reasoning has a huge gap in? :)
Practical assessment method in chemistry Lab
Hello,
Cetyl alcohol is soluble in solvents like acetone and alcohols but not water. Cetyl alcohol is a waxy substance at room temp with a melting temp at around 50 dC.
If I want to dissolve cetyl alcohol in a solvent at room temp, will it dissolve? Or do I need to heat the mixture to CA melting temp?
Originally, I was thinking I would have to heat it. But then I thought there are substances that are solid at room temp but still have the ability to dissolve at room temp...
Thank you.
Kind regards,
Lara.
I bought G4 PAMAM dendrimer from a company but they aggregated. The size of them changed from 5nm to 100nm and I cannot work with them because the NH2 functional groups of dendrimers are not available for a chemical reaction. Please guide me, how can I separate PAMAM dendrimers? Is there any pretreatment?
Indeed, I have observed that there is some scientific journals that listed in Scopus sources of not good quality from scientific point of view. At the same time some Universities are depending on Scoups in a similar manner to that of Thomson & Routers or Clarivate analytics.
I am writing my thesis about metabolomics, and after reading about metabolites and proteins and how these have been measured through time for characterization and kinetics, I think metabolomics could be the one analytical technique that enables universal measurement of all intracellular, and possibly extracellular molecules. Even proteins with intact protein mode, for example. Maybe I'm too naive and inexperienced, and saving for some differences to enable separation (column chemistry), and ionization (ESI v APCI v direct injection), what are your thoughts on this statement?
kindly give the software details and download link
As a requirment in my project, I have to synthesize Formamidinium bromide (FABr). According to the protocols which are mentioned in the articles, I've synthesized this material but I think there is an error in my work?
Does anyone has the experience of this synthesis?
Because in the articles, the authors don't express all the steps, I want to know if there is any critical strategy during the synthesis of FABr and specially in the purification stage of this process.
I would appreciate if you point out a reliable article which has mentioned all the stages of this synthesis with it's details.
Hello,
I need to impregnate the pores of a MOF with cu(acac)2, which I will then reduce under vacuum to copper nanoparticles. I plan on using the incipient wetness approach to do so. However, my MOF will not be in a powder form, but rather a self supported, fibrous mat form ( ). According to my current research, the solid support catalyst (MOF) is typically stirred as the metal precursor solution in chloroform (or other solvent) is added to it, yielding a paste. However, I cannot stir my fibrous mat. Will simple immersion of my mat in the metal precursor solution be sufficient to impregnate the pores of the MOF with the precursor? Or would a drop-wise method of adding my solution work without stirring the MOF? Is there another way around this issue?
Thank you for any answers!
Does anyone know of, or use, commercially produced surfaces for contact measurements (control material)? As an example, is there a producer of PTFE discs with highly controlled surface roughness and chemistry that I can purchase? I have not found any....
I am wondering why some stains do not work by themselves and absolutely need to be paired with a counterstain to work. What is the chemistry behind this process? Is there a nice book that explains this process in depth?
Thank you very much for your answer in advance.
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 come across many reactions like A + B --> products.
How to consider "products" as a species and solve the kinetics in simulation/modelling, as such the reaction is unbalanced by logic of chemistry.
Dear Scholars
I was wondering if anyone can recommend a publication on crude oil chemistry - particularly on SARA (Saturates, Aromatics, Resins, and Asphaltenes) classifications.
Thanks.
So I have some pH = {4, 7, 10} standard buffer solutions from Fisher Scientific. But they must have went bad or I must have contaminated them because when I try to calibrate my pH meter to 4 using the pH 4 standard buffer solution, it calibrates the pH meter to 2 which obviously isn't right because it should be 4 so I can't trust the standard buffer solutions!!!
I need to do some experiments which require that I accurately calibrate the pH meter which means I can't titrate the standard buffers with HCl or NaOH. I have to know the exact quantities. Might seem a little over-the-top, but I want to be really certain about the math.
I intend to prepare my own calibration standards using exact quantities of chemicals. Total concentration should be 0.1 M, volume needs to be 100 mL. I think 0.1 M is a good choice because that should have low ionic strength and not much crazy debye-huckel variations in pH.
I am pretty certain that I know how to prepare a pH = 4 standard buffer solution using acetic acid and sodium acetate. But I am not quite sure how to prepare a pH 7 standard.
First of all, is this exactly how I should prepare a 0.1 M acetate buffer in 100 mL?
According to pubchem the pKa of acetic acid is 4.76. I have a chem textbook which tells me that the pKa is 4.74. Not much difference so I will assume pubchem is right.
HA + H2O --> A- + H3O+
Acetic Acid + H2O --> Acetate + H3O+
Henderson-Hasselbalch Equation: pH = pKa + log([A-] / [HA])
pH = pKa + log([Acetate] / [Acetic Acid])
= 4.76 + log([Acetate] / [Acetic Acid])
For the total concentration:
[Acetic Acid] + [Acetate] = 0.1 M
The simultaneous solution to these equations is about:
[Acetic Acid] = 0.0852 M
[Acetate] = 0.0148 M
pH = 4.76 + log(0.0148 / 0.0852) = 3.9998 etc ... Pretty much exactly 4!
I have glacial acetic acid and sodium acetate.
Glacial Acetic acid is a pure liquid so its concentration is its density / (Formula Weight)
[Glacial Acetic Acid] = [(1.05 g/mL) / (60.05 g/mole)] * (1000 mL / 1 L) = 17.5 M
Basic Dilution Equation:
Initial Volume = (0.0852 M / 17.5 M) * 100 mL = 0.487 mL glacial acetic acid in 100 mL total volume.
Sodium Acetate --> Na+ (aq) + Acetate- (aq)
grams sodium acetate = (0.0148 moles sodium acetate / L) * (82.03 grams sodium acetate / 1 mole sodium acetate) * (1L / 1000 mL) * 100 mL = 0.121 grams sodium acetate
So I can exactly prepare a pH = 4 is 0.1 M acetate solution by adding 487 microliters of glacial acetic acid & 0.121 grams sodium acetate to 100 mL volumetric flask, and bring the volume up to 100 mL with ultrapure deionized water? Swirl to mix.
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I am confused about how to prepare an exactly pH = 7 phosphate buffer solution.
I know the step wise dissociation of Phosphoric Acid. But the problem is that I am not certain about the second dissociation constant.
H3PO4 --> H2PO4- (aq) + H+ (aq)
H2PO4- (aq) --> HPO42- (aq) + H+ (aq)
If I know the second dissociation constant of phosphoric acid I could figure out exactly how to make a pH = 7 standard 0.1 M phosphate buffer solution using phosphate salts.
My undergrad general chem text book is telling me the second Ka is 6.2 * 10^(-8) or the pKa is 7.208 and pubchem is telling me the second the second pKa is 7.09.
Thus I could use the Henderson-Hasselbalch Equation again with the total concentration to figure out the exact quantities. But I am not certain about what the second pKa of phosphoric acid is! Are undergrad chem textbooks just wrong? That's too much of a margin of error.
pH = pKa + log[(K2HPO4) / (KH2PO4)]
Also I was wondering if a 0.1 M solution of NaCl would have a pH of EXACTLY 7? Would it be more or less accurate than making the phosphate buffer?
NaCl is formed by the titration of a strong acid HCl with a strong base NaOH. Therefore the equivalence point of the titration of a strong acid and strong base should yield a pH 7 of neutrality forming NaCl.
So if I dissolved NaCl in water to yield a 0.1 M concentration would the pH be just as good as making that phosphate buffer solution?
I also need to figure out how to make a pH = 10 standard buffer solution.
Any advice? Can you make my life easier?
Thanks so much!
#COVID-19
Coronavirus Covid-19: Current Research. Open Access Publications Chemistry in Coronavirus Research: A Free to Read Collection from the American Chemical Society
I have extracted Manganese dioxide from zinc-carbon battery in order to prepare Manganese fertilizer . but it never dissolve , Why ??
I recently read:
"The perovskite solution for the solvent quenching method (MAPI) recipe was prepared by dissolving 553.2 mg PbI2 and and 181.23 mg MAI in 1 ml anhydrous DMF/DMSO (4:1, v:v) to obtain a 1:0.95 molar ratio solution (PbI2:MAI) with a concentration of 42.96 wt %."
How can one get 553.2 mg of PbI2 and 181.23 of MAI (CH3NH3I) to be dissolved in 1 ml solution to obtain a 1:0.95 molar ration solution when the molar mass for PbI2 and MAI are 461.01 g/mol and 158.97 g/mol respectively.
I am confused. Thanks for the help in advance.
Some studies reveal that SARS-CoV-2 virus activity can be mitigated at the alkaline pH medium (above pH= 7.5). Any explanation about the mechanism or the Chemistry behind this phenomenon.