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How to handle CO2 being evolved during vacuum distillation? |
Suppose there is a solid made of avogadro number of, say, aluminium atoms. This solid is kept at 273 K. According to Maxwell-Boltzmann distribution, all the particles or atoms will not have the same thermal energy. Some atoms are cooler than 273 K, some are much warmer than that etc. But is this true?
I mean, accord... |
><b>Why London Force is greater than dipole-dipole interactions in Alkyl Halides?</b>
[![enter image description here][1]][1]
As we know that most of the time London force is weaker than other forces.Then why in this case it's not so.
According to me,
Due to high charge separation(in C & X) dipole dipole intera... |
Setup: vacuum aspirator pump, distillation apparatus with stirring (instead of a bubbler). Partial vacuum around 5" Hg.
What would you suggest to hold the vacuum set-point? |
What will happen in an exothermic reaction if more than required energy is given?I mean will it produce even more energy which will be highly dangerous or nothing will happen according to le chatelier's principle (as we are trying to carry reaction in backward direction ) |
I know that the first shell can hold up 2, the second and third can hold up to 8, and the fourth 18. But what about after that? |
I know that the first shell can hold up to 2, the second and third can hold up to 8, and the fourth 18. But what about after that? |
Question 2: https://imgur.com/a/MIvqrwU
2nd part of Question 2: https://imgur.com/a/2KChAnM
I mainly looked at the 13C-NMR aspect of this question. Given that there is a 190 peak, it is probably an aldehyde with a CH(which explains the +DEPT sign). The molecular formula also showed a degree of unsaturation of 5, whic... |
Determining structure from C-NMR spectrum, is my answer correct? |
The test is administered by breathing through a tube, and the results become apparent immediately. Indeed, this has something to do with oxidation of alcohol. As soon as the alcohol in the exhale reaches the contents of the test tube, the latter changes its color, and the police guys put you in the handcuffs. Or it doe... |
> Which chemical is used in drunken driver test?
> 1. Acidified K<sub>2</sub>Cr<sub>2</sub>O<sub>7</sub>
> 2. KMnO<sub>4</sub>
> 3. Chromyl Chloride
> 4. H<sub>2</sub>O<sub>2</sub>
On searching on Google, I got the answer as option 1, acidified potassium dichromate, but my questions are:
- How is t... |
Which chemical is used in drunken driver test? |
Question 2: https://imgur.com/a/MIvqrwU
2nd part of Question 2: https://imgur.com/a/2KChAnM
I mainly looked at the $\ce{^{13}C}$-$\mathrm{NMR}$ aspect of this question. Given that there is a peak at $\pu{190ppm}$, it is probably an aldehyde with a $\ce{CH}$ (which explains the +DEPT sign). The molecular formula also ... |
<b>Why London Force is greater than dipole-dipole interactions in Alkyl Halides?</b>
>[![enter image description here][1]][1]
As we know that most of the time London force is weaker than other forces. Then why in this case it's not so?
According to me, due to high charge separation (in C & X) the dipole-dipole... |
The more electropositive element should displace metal from it's salts' solution. This can be seen in reaction of copper salts with iron. But, if you try using for example potassium metal as the more electropositive metal in a displacement reaction you don't get a result since potassium will react with water before it ... |
The more electropositive element should displace metal from it's salts' solution. This can be seen in reaction of copper salts with iron. But, if you try using for example potassium metal as the more electropositive metal in a displacement reaction you don't get a result since potassium will react with water before it ... |
The more electropositive element should displace metal from it's salts' solution. This can be seen in reaction of copper salts with iron. But, if you try using for example potassium metal as the more electropositive metal in a displacement reaction you don't get a result since potassium will react with water before it ... |
It is not always a good idea to focus only on $\ce{^{13}C}$-$\mathrm{NMR}$ when you are doing structure elucidation on unknown compound using spectral data. Yes, $\ce{^{13}C}$-$\mathrm{NMR}$ gives you valuable info, so does FTIR to some extent. Yet, $\ce{^{1}H}$-$\mathrm{NMR}$ gives the most info about the compound as ... |
It is not always a good idea to focus only on $\ce{^{13}C}$-$\mathrm{NMR}$ when you are doing structure elucidation on unknown compound using spectral data. Yes, $\ce{^{13}C}$-$\mathrm{NMR}$ gives you valuable info, so does FTIR to some extent. Yet, $\ce{^{1}H}$-$\mathrm{NMR}$ gives the most info about the compound as ... |
It is not always a good idea to focus only on $\ce{^{13}C}$-$\mathrm{NMR}$ when you are doing structure elucidation on unknown compound using spectral data. Yes, $\ce{^{13}C}$-$\mathrm{NMR}$ gives you valuable info, so does FTIR to some extent. Yet, $\ce{^{1}H}$-$\mathrm{NMR}$ gives the most info about the compound as ... |
Since pKa of primary amides are close to alcohols, will there be an acid base reaction between amides and LiAlH4 besides reduction? |
While comparing the strengths of o-nitrophenol and p-nitrophenol, p-nitrophenol is found to be more acidic. The reason I studied for this is H-bonding in o-nitrophenol which makes the acid more stable, making it a weak acid.
But between o-methoxyphenol and p-methoxyphenol, o-methoxyphenol is more acidic because of mor... |
While comparing the strengths of *o*-nitrophenol and *p*-nitrophenol, *p*-nitrophenol is found to be more acidic. The reason I studied for this is $\ce{H}$-bonding in *o*-nitrophenol which makes the acid more stable, making it a weak acid.
But between *o*-methoxyphenol and *p*-methoxyphenol, *o*-methoxyphenol is mor... |
> Determine the structure of the compound whose spectral data is given below and explain your reasoning (5 marks for structure, 15 marks for reasoning). The peak at 7.27 ppm does not belong to the compound. What is the source of this peak?
(2.5 marks) Looking at the full spectrum you will see small peaks at about 4.2 ... |
What will happen in an exothermic reaction if more than required energy is given? I mean, will it produce even more energy which will be highly dangerous or nothing will happen according to Le Chatelier's principle (as we are trying to carry the reaction in an opposite direction)? |
With the addition of aqueous NaOH to an aspirin solutions in water the reaction will yield products of sodium acetylsalicylate and water. I would like to measure the amount of sodium apsirin formed that is disolved in water right after the NaOH reaction.
Attempt for the solution:
Given that sodium acetylsalicylate... |
Since $\mathrm{p}K_\mathrm{a}$ of primary amides are close to alcohols, will there be an acid-base reaction between amides and $\ce{LiAlH4}$ besides reduction? |
In the wikipedia article on gravimetric analysis, https://en.wikipedia.org/wiki/Gravimetric_analysis, it is said that gravimetric analysis was used to determine the atomic masses of many elements in the periodic table to six figure accuracy. There are, however, no references to that claim.
Could someone please tell ... |
How can one determine an atomic mass using gravimetric analysis? |
In the [Wikipedia article on gravimetric analysis](https://en.wikipedia.org/wiki/Gravimetric_analysis) it is said that gravimetric analysis was used to determine the atomic masses of many elements in the periodic table to six figure accuracy. There are, however, no references to that claim.
Could someone please tell... |
How can one determine an atomic mass with high precision using gravimetric analysis? |
How do we know that there are different types of orbitals? For example, what evidence is there for the existence of $\mathrm{p}$ orbitals instead of there being multiple $\mathrm{s}$ orbitals (for example, why isn't the electronic configuration of sodium $\mathrm{1s^1, 2s^2, 2s^2, 2s^2, 2s^2, 3s^2}$ instead of $\mathrm... |
Nice to meet you! We are studying the chalcogens at school. I should prove (show) the acid nature of $H_2S$ by writing two chemical interactions.
I am really sorry if the terms I am using aren't the right ones. It's the first time I've ever used this part of the language. Which reactions should I write, and why? I t... |
We are studying the chalcogens at school. I should prove (show) the acid nature of $\ce{H2S}$ by writing two chemical interactions.
I am really sorry if the terms I am using aren't the right ones. It's the first time I've ever used this part of the language. Which reactions should I write, and why? I think the first... |
I am doing some research regarding carotenoids and beta-carotene. After extracting the sample, I have not been able to find a way to measure antioxidant activity of BC. I have 0.1mM of DPPH solution dissolved in methanol, but I just read that you cannot use DPPH to measure beta carotene free radical inhibition. Is this... |
How is antioxidant activity of carotenoids determined? |
> An ideal gas, molar heat capacity $C_V=\frac{5}{2}R,$ is expanded adiabatically against a constant pressure of $1\ \mathrm{atm}$ until it doubles in volume. Given initial temperature of $25\ \mathrm{^\circ C}$ and initial pressure of $5\ \mathrm{atm}$, calculate final $T$ (etc.).*
The author uses the First Law to ... |
With the addition of aqueous NaOH to an aspirin solutions in water the reaction will yield products of sodium acetylsalicylate and water. I would like to measure the amount of sodium apsirin formed that is disolved in water right after the NaOH reaction.
Attempt for the solution:
Given that sodium acetylsalicylate... |
I am doing some research regarding carotenoids and beta-carotene. After extracting the sample, I have not been able to find a way to measure antioxidant activity of beta-carotene. I have $\pu{0.1mM}$ of DPPH (2,2-diphenyl-1-picrylhydrazyl hydrate) solution dissolved in methanol, but I just read that you cannot use DPPH... |
I am doing some research regarding carotenoids and beta-carotene. After extracting the sample, I have not been able to find a way to measure antioxidant activity of beta-carotene. I have $\pu{0.1mM}$ of DPPH (2,2-diphenyl-1-picrylhydrazyl) solution dissolved in methanol, but I just read that you cannot use DPPH to meas... |
When calculating equilibrium constant with partial pressures if there is a solid involved should we consider it in the total number of moles in mole fraction? |
Well, interesting question, I would re-word your question as "How can one determine an atomic mass with high **accuracy** using gravimetric analysis? Precision simply implies that you repeated a measurement and it agrees very well with *itself* even though it may be wrong. What we desire is high precision *and* high ac... |
How can one determine an atomic mass with high accuracy using gravimetric analysis? |
Well, interesting question, I would re-word your question as "How can one determine an atomic mass with high **accuracy** using gravimetric analysis? Precision simply implies that you repeated a measurement and it agrees very well with *itself* even though it may be wrong. What we desire is high precision *and* high ac... |
To solve the problem, think about what is the condition for a radial node- what happens to the density $|\Psi_{\textrm{3s}}|^2$ at a node? First some definitions: $r$ is the distance from the nucleus and $a_0$ is a constant distance called the Bohr radius (=0.5291 Å).
>! The density, given by $$|\Psi_{\textrm{3s}}|... |
Radius of sphere = 20nm
pH = 6
I can find the molar concentration of H+ and subsequently the number of H+ , but I am getting a fractional number (~ 2 x 10-2). This is obviously wrong as there should be atleast 1 proton in a compartment which has an acidic pH. What am I doing wrong?
Thanks in advance.
|
How to calculate the number of protons in a sphere given the volume and the pH? |
I'm writing this to show there is no solution. I'm hoping there is a flaw in my answer showing the way to a solution.
The key question, as the OP already stated, is what the two triplets at 6.2 and 7.4 ppm arise from. As they are the only multiplets in the spectrum, it makes sense to assume they couple with each oth... |
I am looking for a software package which can take a unit cell (and lattice parameters, etc.) and from that generate a crystal lattice. Ideally it will have functionality for orthorhombic, hexagonal, and other types of unit cells which are slightly less trivial than a cubic lattice.
Finally, it should work for molec... |
Software for generating a lattice from a unit cell for molecular crystals? |
I understand that Boltzmann's probability distribution gives the relative probability of one microscopic state in comparison to the other (P1/P2) but I don't know how exactly to understand this.
For example when looking at Hydrogen's ground state and Hydrogen's first excited state at some temperature T, let's say th... |
Interpretting relative probabilities based on Boltzmann's probability distribution? |
The spherical radius of a nano-droplet of a solution ($\mathrm{pH}$ of which is $6$) is given as $\pu{20nm}$.
I can find the molar concentration of $\ce{H+}$ and subsequently the number of $\ce{H+}$ ions, but I am getting a fractional number ($\approx 2 \times 10^{-2}$). This is obviously wrong as there should be a... |
The gas pressure equals the external pressure during isothermal irreversible expansion. To maintain P(gas)=P(ext), heat is supplied reversibly. By this reason delta S(surr) must be calculated above. Am I clear? |
I'm writing this to show there is no solution. I'm hoping there is a flaw in my argument leading the way to a solution.
The key question, as the OP already stated, is what the two triplets at 6.2 and 7.4 ppm arise from. As they are the only multiplets in the spectrum, it makes sense to assume they couple with each o... |
I am currently writing a lab report about the formation constant of FeSCN2+. All I could find online was a formation constant at 25 degrees C (890), which was 70% higher than the experimentally measured value at 21.7 degrees C (292). I was hoping to use Van't Hoff's equation to calculate the accepted value at 21.7 degr... |
The gas pressure equals to the external pressure during isothermal irreversible expansion. To maintain P(gas)=P(ext), heat is supplied reversibly. By this reason delta S(surr) must be calculated above. Am I clear? |
Im writing up a lab report at the minute and part of it concerns ions in solution and how they affect conductivity. I've been doing lots of reading and I think ive got the grasp of most of it, but its left me with a few questions.
>Symbols used:
> Resistance ($R$), Resistivity ($\rho$), Conductance ($G$), Cond... |
I am currently writing a lab report about the formation constant of $\ce{FeSCN^2+}.$ All I could find online was a formation constant at $\pu{25 °C}$ $(890),$ which was 70% higher than the experimentally measured value at $\pu{21.7 °C}$ $(292).$
I was hoping to use van't Hoff's equation to calculate the accepted val... |
I am trying to figure out the structure of the compound $\ce{C3H5NO}$ given just the following data from the 1H NMR spectrum:
> $\delta 5.8 ~ \text{(singlet, 1H)}; \delta 6.2 ~ \text{(triplet, 2H)}; \delta 7.4~ \text{(triplet, 2H)}$
From 2-2-1 combination I have the following candidates:
[![enter image descr... |
As pointed out in the comments, the concept of pH as a thermodynamic property of nanodroplets does not quite make sense unless the nanodroplets are in equilibrium (stable). If they are in equilibrium you can still apply the equation
$$\textrm{pH}=-\log_{10}(a_{\ce{H+}})$$ but now you have to be aware that the activit... |
I have pepsin powder which is now hydrated by humidity. Now i want to convert it BACK to powder form. How to do it?
|
How to convert Pepsin into powder form? |
I have pepsin powder which is now hydrated by humidity. Now i want to convert it BACK to powder form. How to do it? |
I have pepsin powder which is now hydrated due to humidity. I want to convert it back to the powder form. How to do it?
I don't have access to a freeze-dryer. |
How to convert pepsin into powder form? |
I have pepsin powder which is now hydrated due to humidity. I want to convert it back to the powder form. How to do it?
I don't have access to a freeze-dryer but let me know also about freeze-drying of pepsin. |
I have pepsin powder which is now hydrated due to humidity. I want to convert it back to the powder form. How to do it?
I don't have access to a freeze-dryer .
I prefer any cheap procedure other than freeze-dryer . |
We know, generally, that the keto tautomer is more stable than the corresponding enol tautomer. I would appreciate an explanation that goes beyond the thermodynamic reasoning, too.
In the nitroso-oxime tautomerism, the nitroso form is analogous to keto isomer and the oxime is analogous to the enol form.
Then why is... |
Why is the oxime tautomer more stable than its corresponding nitroso isomer? |
In NMR a spectrum consists of noise and peaks. While steps, such as repeated scans or smoothing of the spectra can reduce noise some still remains. As such one step usually taken is to bin the data so that only peaks are chosen, usually with a threshold and finding maxima/minima.
This raises the question however, whic... |
I'm writing this to show there is no solution. I'm hoping there is a flaw in my argument leading the way to a solution.
The key question, as the OP already stated, is what the two 2H triplets at 6.2 and 7.4 ppm arise from. As they are the only multiplets in the spectrum, it makes sense to assume they couple with eac... |
(1) $\ce{PH3-> P + 3/2 H2}$
Is the **decomposition** of phosphine on tungsten surface at low pressure is a pseudo first order reaction because this does not depend on the concentration of phosphine but on the surface area of tungsten covered by phosphine? But why for determining order of this **physisorption** proce... |
I was thinking about taking Mercury out of Mercury(ii)nitrate is it possible?
I've tried putting chunks of Fe into it, I've got the logic from the voltaic table ( where Fe is on the left side of Hg, so I think it would get it out of the compound). Can anyone please correct me and show me the right way? I've tried sear... |
I was thinking about obtaining mercury from mercury(II) nitrate. Is it possible?
I've tried putting chunks of Fe into it, I've got the logic from the voltaic table (where Fe is on the left side of Hg, so I think it would get it out of the compound). Can anyone please correct me and show me the right way? I've tried se... |
>1) For what condition do the equations [6] and [7] apply? I think that [7] is for strong electrolytes at low concentration though im not sure. So what about at high concentrations of strong electrolytes? What about weak electrolytes? 2) When would you use equation [6], when would you use equation [7]? Are they equiv... |
This is the picture that goes with the question:
[![enter image description here][1]][1]
Notice that the scale of the chemical shift increases with the strength of the magnetic field B. This means they are using the $\tau$ scale instead of the $\delta$ scale. The modern description of the signals would be 10 - x,... |
Thanks to the fine work by Karsten Theis the remaining task is **much** easier (well, it's actually possible).
You can use chemspider to generate a [library of plausible compounds][1]:
[![enter image description here][2]][2]
and then use screen the compounds based on known shift patterns or a spectral [simula... |
Thanks to the fine work by Karsten Theis the remaining task is **much** easier (well, it's actually possible).
You can use chemspider to generate a [library of plausible compounds][1]:
[![enter image description here][2]][2]
and screen the compounds based on expected shift and multiplicity patterns or a spect... |
Thanks to the fine work by Karsten Theis the remaining task is **much** easier (well, it's actually possible; please read the answers by Karsten Theis which explains that the shifts reported in the OP are incorrectly referenced).
You can use chemspider to generate a [library of plausible compounds][1]:
[![enter ... |
This is the picture that goes with the question:
[![enter image description here][1]][1]
Notice that the scale of the chemical shift increases with the strength of the magnetic field $B$. This means they are using the $\tau$ scale instead of the $\delta$ scale. The modern description of the signals would be $\del... |
I understand how carbon dating works, though I do not understand why it doesn't happen while a creature is living. Because while we are alive we still have carbon 14 in us, so shouldn't it work? |
Why does radiocarbon dating only work in nonliving creatures? |
Thanks to the fine work by Karsten Theis the remaining task is **much** easier (well, it's actually possible; please read the answers by Karsten Theis which explains that the shifts reported in the OP are incorrectly referenced). The corrected chemical shifts (from his answer) are:
$$\begin{align} &\delta\ 2.63 \tex... |
There are plenty of [good sources online][1] explaining the principle behind [radiocarbon dating][2]. For instance, the [wikipedia][3] explains:
> During its life, a plant or animal is in equilibrium with its surroundings by exchanging carbon either with the atmosphere, or through its diet. It will therefore have th... |
So our teacher asked us a simple question in the classroom:
> What happens when Ar and HCl are mixed at 77 K?
and no other information was given.
We replied various possible answers for that such as Debye bond will form between Ar−HCl, force of attraction is proportional to the inverse sixth power of Ar−HCl in... |
What happens when Ar and HCl are mixed at 77 K? |
Thanks to the fine work by Karsten Theis the remaining task is **much** easier (well, it's actually possible; please read the answers by Karsten Theis which explains that the shifts reported in the OP are incorrectly referenced). The corrected chemical shifts (from his answer) are:
$$\begin{align} &\delta\ 2.63 \tex... |
Thanks to the fine work by Karsten Theis the remaining task is **much** easier (well, it's actually possible; please read the answers by Karsten Theis which explains that the shifts reported in the OP are incorrectly referenced). The corrected chemical shifts (from his answer) are:
$$\begin{align} &\delta\ 2.63 \tex... |
Can Michaelis Menton constant be zero in the Michaelis Menton Equation, or is this a non-zero constant?
I am applying the equation in epidemiology so I wanted to assume that it is zero but I am not sure if it is possible for this constant to be zero? |
Can Michaelis Menton constant be zero in the Michaelis Menton Equation, or is this a non-zero constant? |
Can Michaelis-Menten constant be zero in the Michaelis-Menten Equation, or is this a non-zero constant?
I am applying the equation in epidemiology so I wanted to assume that it is zero but I am not sure if it is possible for this constant to be zero? |
Can Michaelis-Menten constant be zero in the Michaelis-Menten Equation, or is this a non-zero constant? |
What is the scientific term for the separation of dust particles from air by suction through a specialized flask in a way similar to the operation of a bong ?
|
What is the scientific term to describe the operation of a bong? |
It does not make sense for the constant to be zero. The constant is usually expressed as follows:
$$ K_M = \frac{k_{\mathrm{reverse}} + k_{\mathrm{catalytic}}}{k_{\mathrm{forward}}} $$
Since the $k$ values are strictly non-negative, the constant would only be zero if $k_{\mathrm{reverse}} = k_{\mathrm{catalytic}}... |
Colligative properties depend on the number of solute molecules? |
> Colligative properties are properties that are affected by the number of solute molecules dissolved in the solution. True or false?
I think the statement is false, and the correct one should use "number of solute particles". I asked my TA and he said the molecule version is true, although I show him an example tha... |
Do colligative properties depend on the number of solute molecules? |
What is the scientific term for the separation of dust particles from air by suction through a specialized flask in a way similar to the operation of a bong?
|
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