Chemicals - Science topic

Dear Aneel

The degradation temperature of a substance like piperazine can vary depending on several factors, including the purity of the compound, the specific conditions of the heating process, and the presence of any impurities or additives. Piperazine is known to start decomposing at temperatures around 160-180°C (320-356°F), but the exact temperature at which significant degradation occurs might differ based on the context.

If you're working with piperazine in a specific application or industry, I would recommend referring to the relevant safety data sheets (SDS) or scientific literature for more accurate and up-to-date information on its degradation temperature under the conditions you're interested in.

Hello Sohaib Ramadan

Here are some interesting articles which may be helpful. I found them quite interesting!

Best.

Ali Safaa I think that depends on what purpose you need that solution for. For example, if you needed to make a solution with a concentration of just the chromium(IV) ion in an analytical study, you would need half of that mass you calculated above because for every mole of potassium dichromate, there are two moles of chromium(IV). Here I post the stoichiometric relationship that I made to calculate that concentration and I hope it makes sense.

Thank you for the information and for the fascinating question. You presumably already know about the EU's approach https://echa.europa.eu noting that this overall topic is highly relevant to UCL's Warning Research Centre https://www.ucl.ac.uk/sts/warning-research-centre led by Carina Fearnley. Taking a wide approach to warnings is so important https://doi.org/10.1007/978-94-017-8598-3_5

Anthony Hutin

I tried both ways and both resulted in IFT decline.

Okay, I see. My gut feel then is that the dextran is adjusting the osmotic strength of the buffer. If so, PEG may be a valid substitute. This of course does not tell us which size to use, or how dextran and PEG of the same size would compare (I guess data on osmotic strengths could be found in the literature). The osmotic strength will definitely be affected by both size and concentration and you may have to figure out these parameters empirically if the technique is new. Good luck.

Sir,

To the best knowledge of me, this company has a wide range of chemicals, some of them can be seen in perfect articles in some well-known journals, such as Cell.The products from ChemFaces, China is OK, but you have to make sure that you are contacting a qualified and honest dealer or the correct contact information of the manufacturer.

Good luck!

Enzymatic desizing can achieve effectively all types of starches from textiles and at workable temp. range.

The pH of pure potassium sulfate (K₂SO₄) aq. sol. can be predicted as equivalent to that for Na₂SO₄ aq. sol. (neither K⁺ or Na⁺ contribute to pH, since both its hydroxides are strong bases). For a RG discussion on the pH of pure sodium sulfate (Na₂SO₄) aq. sol.:  https://www.researchgate.net/post/What_do_you_call_the_electrolyte_of_sodium_sulfate_a_base_an_acid_or_neutral

Hi Akila,

You may make an inquiry at Alfa Chemistry, they offer kinds of good-quality chemicals.

Absolutely YES , here some literature:

One very efficient suite of system to perform this task is CODESSA:

but this task has a long long story starting from seminal Hansch studies (extrathermodynamic approach):

I think the public perception about chemistry and chemicals is negative due to environmental education. Nevertheless, drugs, plastics, textiles, dyes, fertilizers, pesticides etc. are still purchased and used on large scale.

1 gram/pound=2204.6244 mg/kg

Also refer this for more details:

Adding carbon dioxide gas (CO2) will reduce the pH as it will form carbonic acid in the presence of water. Sparging with air will increase the pH when excess CO2 is present in the system; air will remove CO2.

Dear Gajendra Pal Singh Raghava

I think you can get an important informations about non-peptide carrier vector in a review article titled "Recent advances in cell-penetrating, non-peptide molecular carriers" has a DOI : 10.1016/j.ijpharm.2007.08.016.

Regards

Have you tried VulcanChem or Zinc15?

Hi,

You may make an inquiry at Alfa Chemistry, they offer kinds of chemicals for research use.

Using Gas Chromatography (GC) analysis to find the composition of complex hydrocarbon. Generally we use the average formula for Bio diesel based on the molecular weights of components.

Mi, abuelo, mi padre, mi madre, mis hermanos....hasta un sobrino chiquitito que nacio hace poco...Todos araaamos la tieeerra....

Hi,

You may make inquiry at Alfa Chemistry. They may provide the chemical.

https://www.alfa-chemistry.com/order.htm

You may get a very good benchmark study in Acc. Chem. Res. 2008, 41, 157−167

You may go for Plant extract or nutrient supplement like single super phosphate to crash it naturally by over crowding that.

Valuable question.

Following to learn.

Can you dissolve oleylamine into ethanol? I'm working in CZTS and CZTSe, too.

Greeting to you Dear , I think this link will be useful for you

https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Supplemental_Modules_(Organic_Chemistry)/Acid_Halides/Properties_of_Acyl_Halides

Dear Abdelaziz Abuyamin find attached.

Biosynthesis of plants based support materials have gained much interest as compared to the conventional adsorbents due to their plentiful existence, low-cost, nontoxic nature, high-efficiency, and as well as environmental friendly nature. It has been found that natural abundance, biocompatibility, hydrophilicity, biodegradability and anti-bacterial properties are some important characteristic features of plants derived materials which make them distinctive from the other adsorbent materials. Besides these, metal nanoparticles exhibit a broad antimicrobial spectrum.

C1 x V1= C2 x V2

C1 is the initial concentration(37%) C2 is the diluted concentration(5%)

for example if you want to prepare 100ml of 5% solution you do the following:

37 x V1= 5 x 100 => V1=13.51ml

So you must take 13.5 ml out of your initial solution (37%) and add them to a 100 ml volumetric flask then add distilled water until the bottom of the meniscus is level with the horizontal line on the neck of the flask.

See work by:

"Hage SR, Nieder A (2016) Duel neural network model for the evolution of speech and language. Trends Neurosci 39:813-829."

in which they devote some text to laughter and brain circuits and which can be downloaded from RG.

For volatile organic acids HPLC and for phenols GC could be used in analysis of greywater. But still I endorse Bruce Levison.

Yes, but with plenty of water

Hi,

You may buy dyes at Alfa Chemistry. There are different kinds of dyes, you can inquiry anytime you want.

Hi all! Did anyone actually tested if the -20C-stored or +4C-stored stock solution of CoCl2 is as potent as a freshly prepared solution?

Hi,

You can buy it at Alfa Chemistry, the link is below:

Most weeds are not harmful, and there is no need to be fully controlled. But we must avoid resistance to herbicides. The use of rotation in herbicide application can be a good way to reduce herbicide resistance.

Eventually, the use of herbicides is a cheap and easy way to control weeds in wide farms.

Acetic acid is used in place of hypochorite

Potassium aluminosilicates can be used

https://www.britannica.com/science/alkali-feldspar#ref104646

Hello

You can use aqueous solutions of colchicine, trifluralin or oryzalin. In our study, oryzalin was recommended due to its advantages including low toxicity, low cost and its ability to increase ploidy levels at low concentrations.

Dear khelfaoui,

I would rather suggest, you must do some preliminary trials for both the process; first chemical activation then pyrolysis and vise versa, so you could better understand at which process you are getting good results. Also, its depends upon the pyrolysis temperature, time, and most importantly properties of raw material like it woody, grass or manure.

The following side effects are the most common or most dangerous effects of drugs that affect the nervous system: - Stroke; ... But the most dangerous thing in the case of headaches is to turn into the so-called chronic daily headache in which the patient takes painkillers on a daily basis to become addicted without Refer to the doctor to find out the cause and treatment.

It depends on what you mean by "stability": that due to the inherent chemistry of the solute, that due to interactions with a solvent, or that due to external factors like temperature or sunlight. They find jars with vinegar at the bottom of the sea in ancient Greek ships, and the vinegar is still vinegar. You can call it a dilute acetic acid aqueous solution. On the other hand, hydrogen peroxide solutions tend to be more stable when they are more concentrated (you'd still better keep them in a fridge and away from sunlight). Then sodium chloride solution for instance will stay sodium chloride at any concentration just about forever. Then of course things may be completely different with other solvents: one reagent may completely degrade in water (hydrolyze), but be perfectly stable in polar aprotic solvents, etc. It very much depends on the overall chemistry of the system. There is no simple "yes" or "no" answer here.

Thank you all to given me your valuable comments.....

Keep in refrigerator is best if u want to use it for analytical purpose.

Hi Slimane,

Nice question, and an excellent pic too !!

A good deal has been answered on the Chemistry portal to which Prashant directed us. But strangely, a simple aspect has been ignored ! So I will suggest the same as my two-penny bit:

Have we noticed that while the rain droplets are likely to be cold due to continuous evaporation on the way, the ground is likely to be hot (particularly in countries like where Slimane or myself are located !) ? And there is heterogeneity of temperature both ways !

That is, at some spots, air trapped in surface pores is hot enough, and the rain drop falling is simply cold enough for the bubbles to form.

At other spots they may be not so well matched !!

Dunno if that makes any sense ?!

Cheers !

-Sanjay

Increase level of antioxidant enzymes such as peroxidase, SOD, PAL, Chitinase can be seen.

Phenolic and flavonoid are also changing in a greater way.

+1 each to Brenda's and Chris's responses.

Whether this will light an LED depends on a two things: first is the relevant voltage. The electrochemical system you have appears to have 1.4 V of potential. If that is sufficient to turn on your LED, that's the first part. The second is how much power the system can output. If the electrochemical system is effectively a battery then if you start to pull current through the LED, the potential should not move too much and you're good. If it is more like the open circuit of a corroding sample, then it may not be able to output much current without the potential shifting quite a bit.

Easiest test, provided the turn on voltage is sufficiently low that 1.4 V will trigger, is to follow Brenda's advice: connect your LED to the two electrodes and see if it turns on.

Dear Sherif Arafa,

Was my answer helpful? If so, please acknowledge it by recommending it.

Recommending helpful, quality answers is a quick and easy way to say "thanks", and it encourages wider participation.

Best wishes in your research. AF

This is a freshman chemistry student question-not a researcher's question. See some textbooks.

Testing of % of Ca ethoxide as patteren follow for NaOC2H5

Many organisms pathogenic to plants reside in the soil and can contaminate even "soilless" mixes used to propagate plants in nurseries. Using pathogen-free potting media is an essential starting point for producing nursery container stock that is free of soil-borne plant diseases. Diseased plant material that is outplanted can introduce pathogens from the container into the new planting site. If conditions are suitable, these pathogens can affect not only the transplanted stock but may spread beyond the planting sites into the environment where thay can affect other vegetation.Heat treament is often referred to as sterilization, but temperatures routinely used to heat soil will not result in completely sterile soil / potting media. The goal is to heat the potting mix to a point that kills the plant pathogens of concern.

Heat treatment of soil or potting mix involves reaching a target temperature for a specific minimum period of time. In general, lower temperatures require a longer heating time to achieve the same degree of kill of plant pathogens. Moist heat is also more effective than dry heat at any given temperature.

The entire mass of soil or potting mix needs to reach the desired temperature for the minimum treatment time. Begin timing when the coolest area of the treated mix reaches the target temperature. Uniformity of heating can be affected by a variety of factors, including variation in compaction, moisture, clods, bin shape, and method of heating. The coolest part of the heated mix may be at the center or near the edge, depending on these factors.

Ca²⁺ + 2HCO^₃- <=> CaCO₃ + CO₂ + H₂O happens in solution and is a reversible reaction.

Try BRENDA at www.brenda-enzymes.org. Search on the name of the enzyme. This database can link you to references in which inhibitors of the enzyme are mentioned.

A heterogeneous system can only be described as homogeneous to a pre-specified or required standard error. There will be a minimum mass required to meet that standard error. The standard error can also be determined practically by experiment.

You can improve stability by using the salt of diamine or its acidified solutions. And, of course, storaging under argon or nitrogen, in solid state is preferrably for all air-sensetive compounds.

It can be ecotoxic in aspect of pollution with non-biodegradable polymers. This is heavy problem for the living creatures in oceans nowadays.

If an RI detector is used, the mobile phase mode must be isocratic (50/50 ACN/water?). The sample would also have to be a 'neat' sample since the RI detector is very insensitive.

Dear Sir. Concerning your issue about the chemical components of the hydrogel. Hydrogel products constitute a group of polymeric materials, the hydrophilic structure of which renders them capable of holding large amounts of water in their three-dimensional networks. Extensive employment of these products in a number of industrial and environmental areas of application is considered to be of prime importance. As expected, natural hydrogels were gradually replaced by synthetic types due to their higher water absorption capacity, long service life, and wide varieties of raw chemical resources. Literature on this subject was found to be expanding, especially in the scientific areas of research. However, a number of publications and technical reports dealing with hydrogel products from the engineering points of view were examined to overview technological aspects covering this growing multidisciplinary field of research. I think the following below links may help you in your analysis:

https://www.sciencedirect.com/science/article/pii/S2090123213000969

https://dspace.mit.edu/bitstream/handle/1721.1/35718/20-462JSpring-2003/NR/rdonlyres/4F188B64-BCAC-4D1F-A096-B47FB5663813/0/BE462lect07.pdf

https://www.staff.ncl.ac.uk/r.w.harrington/hydrogels.html

Thanks

I used to defrost -80C freezers all the time. DNA, RNA, enzymes, and tissue samples should be fine in a -20C freezer for 24 hours as long as they don't thaw completely. Chemicals you'd have to check to make sure they can tolerate the change in temperature. To expedite the process of defrosting the freezers, I would remove everything, unplug the unit safely according to equipment procedures, and then (using thermo resistant gloves because it's cold inside!) as the ice was thawing scrape it off (using plastic) into buckets and use paper towels to wipe up any excess water and ice, leaving the doors and interior compartments open the entire time. This way, the interior of the unit had more time to warm up to completely defrost instead of slowly melting the ice all day. This process took me just a day to do. I'd start in the morning, the ice would be completely melted off by lunch time/early afternoon, and then it would warm up overnight. The next morning, I'd plug it back in and by lunchtime the samples would be back in the -80C freezer.

On that note, however, -80C freezers shouldn't need to be defrosted. I also agree with Artur; if there is poor ventilation/circulation it could cause the freezer to build up with ice. Also, if the refrigerant is low. Perhaps a service call might be needed as a checkup for the freezer?

Dear Chandra,

please refer to the paper in the link:http://www.jsts.org/html/journal/journal_files/2013/12/year2013volume13_06_18.pdf

and the link: https://link.springer.com/content/pdf/10.1007%2FBF02665519.pd

Best wishes

Andrea Calcaterra thanks for the explanation.

As indicated the number of particles (molecules for not dissociating compounds and ions) contribute to the total osmolarity of the solution. In my opinion you may try to preparare a solution without using HCl. This is a strong acid, completely dissociated and contribute to the osmolarity of the solution with a coefficient of 2 in respect to its concentration since one mole generate two ions (so two particles osmotically active).

Hi, I think this paper is useful to you.

Chemical composition, antioxidant and antimicrobial activities of basil (Ocimum basilicum) essential oils depends on seasonal variations

You should heat the fresh Ni2O3 (which is a hydrate) at 250-350^oC.

Thanks a lot Michael! This is great!

The calculation does not seem to make sense to me. The units are not matched up (kg^-1 times g).

do you mean that the toxic chemical is 10ug/kg in a parent substance and the person is ingesting 0.5g per day of the parent substance?

If yes then it should be 10 ug/Kg *0.0005 Kg/day ÷ 50 KgBW

If No then is the person ingesting 0.5 g of the toxic chemical each day?

Dear kiran,

Hydrocarbons are best analysed on GC with FID and ECD detector Please have a look on Literature to use this analytical Technique.

Regards

interesting question

Thanks a lot Dear Djahli,

you can use DOE to generate different combinations to check if any reactions between each other occured.

hope to be hopeful.

Dear Juliette, thanks again for the suggestions! In fact, I don't know a pore size of used silica. And I'm not sure if I can evaluate it. However, you was right, that the critical point was DTT removing. In fact, I'm afraid to lose immobilized silane molecules by treatment of silica in basic solutions at step 8. Thereby I tried sonication in PBS instead of slightly basic solution. And it was successful. Also sonication in aceton to remove F5M at step 10 resulted almost in no fluorescence in control measurements.

Thanks for such nice information kindly provide me reference for the mentioned values.

A simple t-test will tell you if the 2 data sets are significantly different. If they are significantly different it should be clear which gives the nest removal. However, this is statistics, and if the %removal is too small then neither may be significant in the real world

hello abbas einali

I recommend you send email to M.r NIBPOUR, I think he has been Phd student in tarbiat modares university yet, having good experience in laboratory study's suspended sediments sinking in sea water body or M.R. MOHAJERI (mohajeri@srbiau.ac.ir).

I hope you could get good advice.

sincerely you.

According to my little knowledge, sodium hypochlorite (NaClO) is suitable for bleaching many items including the natural fibers of cellulose. It is available in most countries. Hydrogen peroxide is a good bleach but it needs high temperature to whiten "this requires due care".

Sometimes, chemists may combine 2 bleaches on a substrate but please try with small amounts on little fibers with precautions "in the hood". If this works, then one can proceed. Wishing you success.

Nothing more low-cost than buying a bottle of thiobarbituric acid.

Very often we use few layers of 2D h-BN as a substrate on top of SiO2/Si to reduce trap charge (in SiO2) induced carrier scattering in 2D TMD channel. If SiO2 trap charge induced scattering is critical for your 2D TMDs, then the above strategy would be helpful.

Hi Pavan,

Granite processing requires lot of water when compared to other stones. That is why, the quantum of granite slurry is more. Due to its high fineness, zoning all the materials would be little difficult. You can homogenize the particle size before using them.

For characterization, you can use tests like XRF, XRD and SEM.

U can expect changes in the argillaceous-calcareous ratios mainly SiO2 and content CaO which might have an effect on the behavior of both cement pastes and concrete mix.

Also, low CaO and high SiO2 and Al2O3 contents might affect the chemical composition of mixtures.

All the best!

Several things. To reduce small metal colloids you'll need low concentration of metal salt precursor (usually the silver diammine complex for silver nanoparticles and low reactant concentration. Keep the material in colloidal suspension and never dry or filter. Remember too, in air, you're producing silver oxide on the surface - that is silver in the +1 oxidation state. For a more general overview, see:

September 2nd, 2015 Silver colloids and invisible ink https://www.brainshark.com/malvern/vu?pi=560497681&b=1&tx=120486&c1=22

February 18th, 2016 Metal colloids - their preparation, application and characterization https://www.brainshark.com/malvern/vu?pi=529368070&b=1&tx=120486&c1=22