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I am not 100% sure if this is the right place to ask, but please point me in the right direction if not.
I am designing a conductivity meter, and when it comes to displaying the results in mS/cm or µS/cm, I also need to convert to EC. The first place I found was [THIS][1] website which seems great as it has all the... |
Just a few hours ago, I had to deal with a mold problem on some untreated wood and was told by a hardware store worker that bleach was an effective way to deal with the problem, following up with some wood filler paste. I did as I was told and left the room airing out with a window open and two fans running for multipl... |
What compound(s) contribute to bleach's smell and are they dangerous? |
Just a few hours ago, I had to deal with a mold problem on some untreated wood and was told by a hardware store worker that bleach was an effective way to deal with the problem, following up with some wood filler paste. I did as I was told and left the room airing out with a window open and two fans running for multipl... |
I'm reading my Clayden textbook and something keeps nagging me. It says that when we're carrying out alkylation reactions with an enol attacking an alkyl halide with strong base catalysis (with hydroxide), we should keep the base separate from the alkyl halide electrophile to prevent it from performing the SN2 attack i... |
Why can't the N- end of the nitrile anion attack the alkyl halide in an SN2 fashion during an alkylation reaction when OH- can? |
Does electron emit photon when it moves? |
I've been doing some research into graphene for a project I'm working on, and have found that it can potentially be as strong as or even stronger than current superconductors. However, from my current understanding, a substance can only be electrically conductive if it has any free-flowing electrons or ions in its stru... |
How is graphene electrically conductive? |
When the photoelectric effect happens or blackbody radiation happens or when an electron jumps from a ground to an excited state, we say light is emitted by electron.
Now, light is made up of photons. So, can we say that electron emits photons? |
Q 1 By saying oscillator I.e atoms in the wall of black body. Do we mean electron ? Because boundary of any atom is electron right.
Q2 My textbook say that quantum is the smallest value of energy that can be emitted or absorbed. On web , it says charge of an electron i.e 1.6*10$^{-19}$C
so , is this the smallest val... |
Q 1 By saying oscillator I.e atoms in the wall of black body. Do we mean electron ? Because boundary of any atom is electron right.
Q2 My textbook say that quantum is the smallest value of energy that can be emitted or absorbed. On web , it says charge of an electron i.e 1.6*10$^{-19}$C
so , is this the smallest val... |
Would there be a general relation between the pH (say, as measured by a pH strip) and the titration-measured "acid value" of a organic chemical?
The acid value is typically defined as "the mass of potassium hydroxide (KOH) in milligrams that is required to neutralize one gram of chemical substance."
If you determ... |
There is no *theoretical* limit to the number of rows, but...
* On one hand, as Tom Lehrer states, [there may be many others but they haven't been discovard][1].
* On the other hand, after all [s, p, d, f orbitals][2] are filled in the seventh period, there *might* be a new row, or there might be an *extension* of ... |
I understand rust. Fe + H<sub>2</sub>0 → OH<sup>-</sup> → Fe(OH)<sub>2 or 3</sub> and/or Fe<sub>n</sub>O<sub>m</sub>
I understand rust prevention and steels that are resistant to rusting. Trying to google this question gives thousands of answers on prevention.
But what I'm interested in is how to *force* steel ... |
It is known that potential difference on metal/electrolyte or any kind of interphase can't be measured since voltmeter needed to measure it is made of metal which would in contact with metal and solution develop its own potential difference at interphase and as such affect the measurement. To solve this problem, potent... |
How is it Possible to Measure Electrode Potential? |
I wondered if there was a way to determine the number of pi electrons in a conjugated system from UV- vis data. I am Modelling the electrons as particles in an infinite box of length L equal to the length of the conjugated system but I am unsure how to interpret the number of pi electrons- also for systems that have mo... |
For those who understand plastics and epoxies in particular, curious to know if I can add a correctly proportional amount of flexane urethane to epoxy paint without worrying about compatibility issues. IOW is there any non-typical or particular ingredient in epoxy that might prevent successful mixing of the two?
For... |
As a pretense, my understanding of chemistry extends only to a high school honors level.
As I know it, electrons occupy orbitals in which they could possibly be situated, and constantly move around those orbitals by their attraction to the nucleus and repulsion to each other.
Why is it that this specific arrang... |
Why do electrons have to constantly be moving? |
I have a 2L jug of SLA printer-related waste that's been sitting under my desk for a while now and I'd really like to finally figure out how to get rid of it. It contains:
- Ethanol (primarily) and isopropanol, saturated (in the literal sense) with uncured resin (photo-polymers, photo-initiators, binders). Note ther... |
I know pyridine is a polar aprotic solvent (owing to a permanent dipole generated), but if acidified it forms pyridinium cation. So, does it then function as polar protic solvent? |
For those who understand plastics and epoxies in particular, curious to know if I can add a correctly proportional amount of flexane urethane to epoxy paint without worrying about compatibility issues. IOW is there any non-typical or particular ingredient in epoxy that might prevent successful mixing of the two?
For... |
With context to the image shown, is there a reason as to why the conical flask shouldn't be closed with a bung and is there a way to describe this error?
[![][1]][1]
[1]: https://i.stack.imgur.com/JQy6C.png |
Why should the conical flask (apparatus on the right) used in Fractional Distillation be left open (without a bung)? |
I took the liberty of changing the tag to "history of chemistry", because that's the only context in which Bohr's model is still relevant. With that in mind, let's move on.
Sure, a bunch of stationary electrons would have energy and all. What forbids it is the fact that **a static configuration of charges can't be s... |
I understand that HCL with a specific target is used to excite the sample. The atoms in the sample absorbs the photons and re-emits at the same wavelength and the signals are measured by the detector. What about the signal from the source? Let's say only 20% of the energy from the source are being absorbed, wouldn't th... |
In atomic absorption spectroscopy, what signal is measured at the detector? |
> Wouldn't it make more sense that, since they are attracted to the nucleus and repulsed by each other, they find some sort of arrangement where they are all static and the same distance away from the nucleus and an equal distance away from each other (IE, they form one big s-shaped orbital and occupy it such that they... |
When an alcohol reacts with PBr3 the alcohol is going to act as a nucleophile.It attacks the PBr3 leaving Br- behind. The alcohol forms a bond with the PBr3.So,how the oxygen having 3 bonds makes the hydrogen to be more acidic? |
You raised an excellent point, which is not as simple a UV-Vis spectrophotometry because most molecules do no fluoresce or emit light, whereas atoms do. This issue makes an atomic absorption experiment slightly more challenging (at least in principle). The critical question is "what" signal reaches the detector. How do... |
Alcohol acts as a nucleophile in a reaction with $\ce{PBr3}.$ It attacks the $\ce{PBr3}$ leaving $\ce{Br-}$ behind. The alcohol forms a bond with the $\ce{PBr3}.$ How the oxygen having three bonds makes the hydrogen more acidic? |
I have a 2L jug of SLA printer-related waste that's been sitting under my desk for a while now and I'd really like to finally figure out how to get rid of it. It contains:
- Ethanol (primarily) and isopropanol, saturated (in the literal sense) with uncured resin (photo-polymers, photo-initiators, binders). Note ther... |
I have a 3L jug of SLA printer-related waste that's been sitting under my desk for a while now and I'd really like to finally figure out how to get rid of it. It contains:
- Ethanol (primarily) and isopropanol, saturated (in the literal sense) with uncured resin (photo-polymers, photo-initiators, binders). Note ther... |
How do you simplify for Q+w=m(h1-h2)? |
What are the additional chemicals required to make polyurethane foam more viscoelastic? |
$O_2N-CH_2-CO_2H$, $Me_3\overset{+}N-CH_2-CO_2H, NC-CH_2-CO_2H, HO-CH_2-CO_2H$
---
Since only the groups attached to $-CH_2-CO_2H$ are changing, we must look at the point of difference in each group and I was able to figure out that since there is no conjugation, we cannot compare these groups on the basis of the... |
If we apply pressure to a solid , does it change its electric conductivity?I am asking this because in 2020 they announced a superconductor at room temperature but under a pressure of 3/4 of the pressure in the core of the earth.Decreasing pressure decresed the critical temperature.So I was wondering if pressure affect... |
What would be the order of $pK_a$ values of the following:
$\ce{O2N-CH2-CO2H, Me3N^{+}-CH_2-CO_2H, NC-CH2-CO2H, HO-CH2-CO2H}$
---
Since only the groups attached to $\ce{-CH2-CO2H}$ are changing, we must look at the point of difference in each group and I was able to figure out that since there is no conjugatio... |
If we apply pressure to a solid, does it change its electric conductivity? I am asking this because in 2020 they announced a superconductor at room temperature but under a pressure of 3/4 of the pressure in the core of the Earth. Decreasing pressure decreased the critical temperature. So I was wondering if pressure aff... |
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/scUua.jpg
I made up a pretty silly example of a molecule here, but I hope it illustrates my point. It is a dial, but which is the scientifically-preferred order of numbering: left to right, or vice versa?
As you can see in this exampl... |
IUPAC: Would I prioritize low numbering to highest-priority group, OR try to assign lowest numbers overall? |
This question relates to
https://chemistry.stackexchange.com/questions/37784/is-there-any-law-for-ph-conservation-in-chemical-reactions
I had basically the same question, but I did not get the answer I was looking for from the above link.
For me this comes from a cooking background. If I add some acid to ph-neut... |
Can a previously neutral mix of chemicals become acidic or alkaline somehow? |
You raised an excellent point, which is not as simple a UV-Vis spectrophotometry because most molecules do no fluoresce or emit light, whereas atoms do. This issue makes an atomic absorption experiment slightly more challenging (at least in principle). The critical question is "what" signal reaches the detector. How do... |
I think the source of confusion is connecting the general notion of neutrality with pH=7.0. pH is just a scale for representing the concentration of hydrogen ions in water =-log [$\ce{H+}$]. Unfortunately, companies have misused the term to a large extent by marketing.
What do you think about ethanol? Is it neutral?... |
From [Khan Academy][1] starting from 1:25:
My question is Why would sodium ions want to go down just because of one side is more positive than the other, I mean, isn't the same charges repelling each other? I don't think the degree of positivity will enable them to be attracted to each other.
Could anyone help me ... |
Why would sodium ions want to go down just because of one side is more positive than the other? |
Alcohol acts as a nucleophile in a reaction with $\ce{PBr3}.$ It attacks the $\ce{PBr3}$ leaving $\ce{Br-}$ behind. The alcohol forms a bond with the $\ce{PBr2+}.$ How the oxygen having three bonds makes the hydrogen more acidic? |
> What would be the order of $\mathrm{p}K_\mathrm{a}$ values of the following:
>
> - $\ce{O2N-CH2-CO2H},$
> - $\ce{Me3\overset{+}{N}-CH2-CO2H},$
> - $\ce{NC-CH2-CO2H},$
> - $\ce{HO-CH2-CO2H}?$
Since only the groups attached to $\ce{-CH2-CO2H}$ are changing, we must look at the point of difference in each grou... |
> What would be the order of $\mathrm{p}K_\mathrm{a}$ values of the following:
>
> - $\ce{O2N-CH2-CO2H},$
> - $\ce{Me3\overset{+}{N}-CH2-CO2H},$
> - $\ce{NC-CH2-CO2H},$
> - $\ce{HO-CH2-CO2H}?$
Since only the groups attached to $\ce{-CH2-CO2H}$ are changing, we must look at the point of difference in each grou... |
I understand that a hollow-cathode lamp (HCL) with a specific target is used to excite the sample. The atoms in the sample absorbs the photons and re-emits at the same wavelength and the signals are measured by the detector.
What about the signal from the source? Let's say only 20% of the energy from the source are ... |
What signal is measured at the detector in atomic absorption spectroscopy? |
In Bohr's atomic model, an electron can jump to a higher energy level by absorbing a photon with energy equal to the difference in energy between 2 energy levels. This should mean that the electron now has more kinetic energy than it had in the previous orbit. But the velocity of an electron in an orbit is inversely pr... |
If electrons absorb photons to reach higher energy levels in Bohr's atom, why do they have lesser kinetic energy? |
_____________________________
Operatively:
A plane of symmetry in a 2-D projection of a cyclohexane is a sufficient condition.
Alternatively, and lengthy, you conduct an analysis involving conformers but *not limited to the flipping of the ring*, that means you must let the chloromethyl rotate, in your example.
______... |
> What would be the order of $\mathrm{p}K_\mathrm{a}$ values of the following:
>
> - $\ce{O2N-CH2-CO2H},$
> - $\ce{Me3\overset{+}{N}-CH2-CO2H},$
> - $\ce{NC-CH2-CO2H},$
> - $\ce{HO-CH2-CO2H}?$
Since only the groups attached to $\ce{-CH2-CO2H}$ are changing, we must look at the point of difference in each grou... |
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/scUua.jpg
I made up a pretty silly example of a molecule here, but I hope it illustrates my point. It is a dial, but which is the scientifically-preferred order of numbering: left to right, or vice versa?
As you can see in this exampl... |
I am having trouble in this question:
> [![Structure of H₂S₂O₈][1]][1]
> Hydrolysis of one mole of ***peroxy disulphuric*** acid with one mole of water produces :
> - a)two moles of sulphuric acid only
> - b)two moles of peroxymonosulphuric acid
> - c)one mole of sulphuric acid and one mole of peroxy monosulphuric... |
Hydrolysis of one mole of peroxydisulphuric acid with one mol. of water produces? |
My textbook states:
> Metallic hydrides are formed by many d- and f-block elements. Unlike saline hydrides, they are almost always non-stoichiometric, being deficient in hydrogen, for example, LaH$_{2.87}$, YbH$_{2.55}$, etc.
After some research online, I found that non-stoichiometric compounds are so called beca... |
Why are hydrides of transition metals called hydrogen-deficient? |
> What would be the order of $\mathrm{p}K_\mathrm{a}$ values of the following:
>
> - $\ce{O2N-CH2-CO2H},$
> - $\ce{Me3\overset{+}{N}-CH2-CO2H},$
> - $\ce{NC-CH2-CO2H},$
> - $\ce{HO-CH2-CO2H}?$
Since only the groups attached to $\ce{-CH2-CO2H}$ are changing, we must look at the point of difference in each grou... |
[![enter image description here][1]][1]
The above diagram is from our textbook of a Daniel cell.
[![enter image description here][2]][2]
This is a diagram from our textbook showing a Daniel cell when an external voltage opposing the cell potential is a applied. Here ${E}_{ext}$ is less than cell potential.
... |
[![enter image description here][1]][1]
The above diagram is from our textbook for a Daniel cell.
[![enter image description here][2]][2]
This is a diagram from our textbook showing a Daniel cell when an external voltage opposing the cell potential is a applied. Here ${E}_{ext}$ is less than cell potential.
... |
One possible explanation involves atomic size. You need a large enough atom in the middle to stabilize all the occupied orbitals in the octahedral structure; sulfur makes it but oxygen does not.
[This reference](https://studylib.net/doc/8101421/molecular-orbitals-in-sf6) gives the molecular orbitals for sulfur hexa... |
I need an adhesive that can bind to ABS plastic but is highly resistant to ethanol, isopropanol, and water. It's for use in an environment where it will spend a significant amount of time soaking in >95% alcohols, with agitation.
Temperature and pressure requirements aren't a big deal, this is for use at near room t... |
[![enter image description here][1]][1]
According to this textbook, H₂O has lower reduction potential (-0.83 V) than Zn (-0.76 V). This mean zinc is unable to reduce water to hydroxide. If so, why [this video][2] demonstrate that by heating zinc in water, a reaction occurs producing hydrogen gas from the bubbles w... |
Can water oxidize zinc? |
Although, OP indicated the confusion regarding $\delta^\pm $ charge compared with electronegativity, the text body indicated whole lot of confutations over interatomic/intermolecular forces. Thus, I start with the electronegativity.
According to [IUPAC Gold Book]( https://goldbook.iupac.org/terms/view/E01990), elec... |
Context:
In the process of trying to calibrate a number of hygrometers, I came across the method of using wet salt in an airtight container: over time, with a given salt and at a given temperature, the relative humidity in the container will stabilize at a predictable percentage.
The various salts suggested for t... |
Can potassium carbonate be used to calibrate hygrometers? |
This question is about how much the combustion efficiency increases with oxygen enrichment in modern combustion engine designs. A desirable way to answer is to give the fuel efficiency dependency on oxygen percentage of air volume intake.
Some clues can maybe be had from
> Engineering Science and Technology,
Volu... |
How much does oxygen enrichment improve some combustion engines? |
So, we just finished an AP chem lab where the question was basically:
>Given the results of the lab were that $\pu{5 grams}$ of $\ce{CaCl2}$ and $\pu{45ml}$ of water produced a $\pu{13.33 ^\circ C}$ change, find the new temperature change of $\pu{10 grams}$ of $\ce{CaCl2}$ in $\pu{40ml}$ of water.
Our teacher us... |
**Please edit the table to include missing data**
Avogadro constant in the "CRC Handbook of Chemistry and Physics"
| Edition | Years(s) | page | value | CODATA? |
|---------|-----------|-------|--------------|-------------------|
| 1 [(Link)](https://books.google.com/books?id=07AHIEp6vYQC&printse... |
One possible explanation involves atomic size. You need a large enough atom in the middle to stabilize all the occupied orbitals in the octahedral structure; sulfur makes it but oxygen does not.
[This reference](https://studylib.net/doc/8101421/molecular-orbitals-in-sf6) gives the molecular orbitals for sulfur hexa... |
Determine the normality of sulfuric acid solution, given that it gives a yellow color with methyl orange and a red color with methyl red.[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/5hbou.png
can someone help me with this? what should do first?
i know that normality = (g of solute... |
Determine the normality of sulfuric acid solution, given that it gives a yellow color with methyl orange and a red color with methyl red.[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/5hbou.png
can someone help me with this? what should do first?
i know that normality = (grams of so... |
I am studying the methods of removal of [permanent hardness][1] of water, and came across the "synthetic resins method". From my textbook,
> Cation exchange resins contain large organic molecules with $-\text{SO}_3\text{H}$ groups and are water insoluble. Ion exchange resin **$\text{RSO}_3\text{H}$ is changed to $\t... |
How does the treatment of resin R-SO3H with sodium chloride lead to formation of RNa? |
It is a typing mistake. Cation exchange process can be written as
$$\ce{R-SO3^-H^+ (s) + NaCl (aq) -> R-SO3^-Na+(s) + H^+(aq) +Cl^-(aq)}$$
You can immediately see why the resin must be in sodium form for water softening. If the acid form of the resin is used for softening water, what would you get? Extremely st... |
According to both caffeine's [PubChem page][1] and [ChemSpider page][2] its boiling point lies at $\pu{173 °C}$ and its melting point at $\pu{\sim 235 °C}.$ How can it melt at that temperature if it already sublimated at $\pu{173 °C}?$ Or is that the temperature of the triple point? If so, how come none of those pages ... |
Why do we observe much stronger (in most cases complete) fluorescence quenching by $\ce{Pd^2+}$ than $\ce{Pt^2+}?$ I work with complexes of both metals and there is no real 100% explanation I can find why this is the case. I am looking for a full quantum mechanical explanation (if possible). If you know a piece of lite... |
> What would be the order of $\mathrm{p}K_\mathrm{a}$ values of the following:
>
> - $\ce{O2N-CH2-CO2H},$
> - $\ce{Me3\overset{+}{N}-CH2-CO2H},$
> - $\ce{NC-CH2-CO2H},$
> - $\ce{HO-CH2-CO2H}?$
Since only the groups attached to $\ce{-CH2-CO2H}$ are changing, we must look at the point of difference in each grou... |
> What would be the order of $\mathrm{p}K_\mathrm{a}$ values of the following:
>
> - $\ce{O2N-CH2-CO2H},$
> - $\ce{Me3\overset{+}{N}-CH2-CO2H},$
> - $\ce{NC-CH2-CO2H},$
> - $\ce{HO-CH2-CO2H}?$
Since only the groups attached to $\ce{-CH2-CO2H}$ are changing, we must look at the point of difference in each grou... |
I concluded on this question after discussion with the physical chemistry professor at my home university, and reading some physical chemistry books.
Although many references include the concentration of water in the expression of Ka, this is incorrect: the activity of pure water is 1. In dilute solutions, $a(\ce{H2... |
In this reaction scheme, two dehydrobrominations occur. A bulky base is used but both hydrogens are sterically hindered. How is it possible to determine, which one is removed first? Or is this an $E_1$ elimination and the tertiary bromine leaves first?
[![Reaction scheme][1]][1]
[1]: https://i.stack.imgur.com/D... |
E1 or E2 Elimination? Which Elimination occurs first? |
I read about the laboratory method of producing hydrogen peroxide. The chemical reaction in question is: $$\text{BaO}_2.8\text{H}_2\text{O} + \text{H}_2\text{SO}_4 \rightarrow \text{BaSO}_4+\text{H}_2\text{O}_2 + 8\text{H}_2\text{O}$$
I wanted to find out why the *hydrated* form of barium peroxide is used. Apparently,... |
Why is hydrated barium peroxide used in the preparation of hydrogen peroxide? |
Reactants and products are connected with plus signs in a chemical reaction equation, e.g.
$$\ce{CH4 + 2 O2 -> CO2 + 2 H2O}.$$
Is there a strict mathematical interpretation of what looks like sums before and after the reaction arrow. If so, what do the sums represent, and what are the mathematical objects we woul... |
What is the mathematical meaning of the plus signs in a chemical reaction equation? |
I am performing a simple acid-base titration investigating the efficency of different pure antacid compounds, and in my results, I found out that NaHCO3 neutralized the fastest (using a pH by time graph). Later on, I decided to further prove these results, by calculating pKb values for each base, and out of my three ba... |
I have contradictory results in a research paper, how do I proceed with my analysis? |
What is the mathematical meaning of the plus (+) signs in a chemical reaction equation? |
> NH$_2$CO$_2$NH$_4$(s)⇌$2$ NH$_3$(g)+ CO$_2$(g)
I want to calculate K$_p$ for the reaction above, given that the total pressure is $0.63$ bar.
My calculations:
$0.63$ = p(CO$_2$) + p(NH$_3$)
, where p(NH$_3$) = $1/2$ p(CO$_2$) (For every NH$_3$ half a CO$_2$ is needed)
$0.63$ = p(CO$_2$) + ($1/2$ p(CO... |
What is the mathematical meaning of the plus sign (+) in chemical reaction equations? |
Reactants and products are connected with plus signs in a chemical reaction equation, e.g.
$$\ce{CH4 + 2 O2 -> CO2 + 2 H2O}.$$
Is there a strict mathematical interpretation of what looks like sums before and after the reaction arrow? If so, what do the sums represent, and what are the mathematical objects we woul... |
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