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For the reversible reaction of pyruvic acid to 2,2-dihydroxypropanoic acid, we calculated enthalpy using NMR and extrapolated from area (integration) and peaks etc.
We then plotted $\ln K$ vs $1/T.$ I am confused by this questions because I thought enthalpy was temperature dependent.
I guess my question was unc... |
We performed two experiments. Each of the peaks are referring to the methyl peaks in both reactant and product of the hydrolysis reaction.
1. We varied $\ce{H+}$ concentration of the reaction and the peaks move ever so slightly right (up field) as acid concentration increases. Why?
As more acid is added there ... |
Of course there are such solutions. Take, as an example, Sigma-Alrich's offer of methanolic solution of HCl (3 mol/L, e.g. [here][1]), or the dry ones in diethyl ether (e.g., 2 mol/L [here][2]), in cyclopentyl methyl ether (e.g., [here][3]), or in 1,4-dioxane (e.g. 4 mol/L, [here][4]).
[1]: https://www.sigmaald... |
For the reversible reaction of pyruvic acid to 2,2-dihydroxypropanoic acid, we calculated enthalpy using NMR and extrapolated from area (integration) and peaks etc.
We then plotted $\ln K$ vs $1/T.$ I am confused by this questions because I thought enthalpy was temperature dependent.
I guess my question was unc... |
I had a question in my exam,
>Which of the following can be the $n-factor$ of $P_{4}O_{6}$
A. 8
B. 9
C. 10
D. 12
I went for A. and B. options as in cold water $1$ mole of $P_{4}O_{6}$ on hydrolysis give $4$ moles of $H_{3}PO_{3}$, whereas in hot water it gives $3$ moles of $H_{3}PO_{4} + 1$ mole of $PH_{3}$, th... |
I had a question in my exam:
> Which of the following can be the $n$-factor of $\ce{P4O6}?$
> A. 8
> B. 9
> C. 10
> D. 12
I went for options A and B as in cold water $1$ mole of $\ce{P4O6}$ on hydrolysis give $4$ moles of $\ce{H3PO3}$, whereas in hot water it gives $3$ moles of $\ce{H3PO4}$ and $1$ mo... |
We performed two experiments. Each of the peaks are referring to the methyl peaks in both reactant and product of the hydrolysis reaction.
1. We varied $\ce{H+}$ concentration of the reaction and the peaks move ever so slightly right (up field) as acid concentration increases. Why?
As more acid is added there ... |
I have rarely seen any Chromium $\ce{(Cr)}$ square planar complexes and I have been told that $\ce{[Cr(CN)_4]^{-}}$ is tetrahedral...
So, my question is if the statement is actually correct and whether there any other known examples of square planar
complexes of Chromium? |
A mol is a unit but also has a magnitude. How can a unit have a magnitude? And if mole is used to measure an amount of substance than what does mass measure? |
What is the use of both mol and mass representing the same thing i.e. amount of something? |
I have rarely seen any chromium $(\ce{Cr})$ square planar complexes and I have been told that $\ce{[Cr(CN)4]-}$ is tetrahedral.
So, if the statement is actually correct, are there any other known examples of square planar complexes of chromium? |
I came across this article on wikipedia on ethylene glycol stating that it decomposes fairly quickly. I was under the impression that ethylene glycol was dangerous to let leach into soil, but I think I'm mistaken as [wikipedia][1] states
> it [ethylene glycol] breaks down in air in about 10 days and in water or soi... |
What does ethylene glycol decompose to when exposed to air for an extended period of time? |
Ferric chloride can be prepared by dissolving hematite in hydrochloric acid:
$$\ce{Fe2O3 + 6HCl -> 2FeCl3 + 3H2O }\tag{1}$$
But the resulting ferric chloride will be exposed from its formation to water.
After investigating a little, I found that anhydrous ferric chloride, when dissolved in water, hydrolysed an... |
What happens when ferric chloride is dissolved in water? |
I have small amount of rosemary herb powder mixed in a cup of water and it's only party dissolving. I was wondering if there is another powder that can be added to this water solution and dissolve the rosemary completely?
I would like to avoid using rosemary essential oil as it has a certain scent that is different ... |
This doesn't appear to be a rare case and there are plenty $\ce{Cr^2+}$ square planar complexes.
I found 15 square planar complexes with well-determined crystal structures $(R_\mathrm{int} < 10\%)$ by applying the following geometrical restrains:
[![CrEl4 fragmant][1]][1]
- Chromium must have C.N. exactly 4 (T4)... |
This doesn't appear to be a rare case and there are plenty $\ce{Cr^2+}$ square planar complexes.
I found 15 square planar complexes with well-determined crystal structures $(R_\mathrm{int} < 10\%)$ by applying the following geometrical restrains:
[![CrEl4 fragmant][1]][1]
- Chromium must have C.N. exactly 4 (T4)... |
How are catalysts for chemical reactions found?
Given a hoped for reaction, let's take the hydrogenation of carbon monoxide to methanol as an example, do chemists:
1. Proceed directly from some property of the reactants to an obvious (to the initiated) catalyst according to some grand unified theory of chemistry... |
To better illustrate my question, allow me to refer to the case of ammonium chloride, formed through a classic acid-base reaction.
The reaction between ammonia and hydrogen chloride to give ammonium chloride is a neutralization reaction, since ammonia acts as a base and hydrogen chloride acts as an acid.
The reac... |
To better illustrate my question, allow me to refer to the case of ammonium chloride, formed through a classic acid-base reaction.
The reaction between ammonia and hydrogen chloride to give ammonium chloride is a neutralization reaction, since ammonia acts as a base and hydrogen chloride acts as an acid.
The reac... |
Vapour-liquid equilibrium of a two-component ideal solution of trichloroethene (C2HCl3) and trichloromethane (CHCl3) is established at 25 °C. The mole fraction of CHCl3 in the vapour phase is 0.73. What is the mass fraction of C2HCl3 in the liquid phase? Round your answer to two significant figures.
The vapour... |
What is the mass fraction of C2HCl3 in the liquid phase using vapour pressure and mole fraction in gas phase? |
When a compound is synthesised or isolated, it needs to be characterised. This characterisation serves to determine whether something has been synthesised/isolated before and as a template for later generations to compare their synthesised/isolated compounds to the one you have.
Nowadays, one reports NMR and mass sp... |
Vapour-liquid equilibrium of a two-component ideal solution of trichloroethene ($\ce{C2HCl3}$) and trichloromethane ($\ce{CHCl3}$) is established at $25\,°C$. The mole fraction of $\ce{CHCl3}$ in the vapour phase is $0.73$. What is the mass fraction of $\ce{C2HCl3}$ in the liquid phase? Round your answer to two signif... |
> Vapour-liquid equilibrium of a two-component ideal solution of trichloroethene ($\ce{C2HCl3}$) and trichloromethane ($\ce{CHCl3}$) is established at $\pu{25 °C}$. The mole fraction of $\ce{CHCl3}$ in the vapour phase is $0.73$. What is the mass fraction of $\ce{C2HCl3}$ in the liquid phase? Round your answer to two ... |
Here are the electron affinities of the 16th and 17th groups.
[![electron affinities of the 16th and 17th group of the periodic table][1]][1]
The general trend for electron affinity down the group is that it decreases because of the increase in atomic radius.The exception of $\ce{Cl}>\ce{F}$, I can understand i... |
To better illustrate my question, allow me to refer to the case of ammonium chloride, formed through a classic acid-base reaction.
The reaction between ammonia and hydrogen chloride to give ammonium chloride is a neutralization reaction, since ammonia acts as a base and hydrogen chloride acts as an acid.
The reac... |
Why is it the case that for Jahn-Teller effects to occur in transition metals there must be degeneracy in either the $\mathrm{t_{2g}}$ or $\mathrm{e_g}$ orbitals? |
Why must there be degeneracy in the orbitals to have a Jahn-Teller effect? |
[![Image 1][1]][1]
The following reaction has been taken from my study material. This shows that the benzene ring is undergoing a nucleophilic aromatic substitution via benzyne mechanism (presence of a strong base like $\ce{NaNH2}$). My question is:
**Why is substitution preferred at the ortho position?**
The ... |
I need a little help on answering a question which popped into my head while I was reading about gas laws:
> Suppose that I have three canisters, each holding a different gas of
> unknown identity [let's call them gasses A, B, and C] . I also happen
> to have another tank of a different volume in which these gasse... |
Is chemical equilibrium and dynamic equilibrium the same thing? Both point to the reversible reactions and no net changes in concentration of product and reactant.
Dynamic equilibrium from Wikipedia:
In chemistry, and in physics, a dynamic equilibrium exists once a reversible reaction occurs. Substances transitio... |
What is the difference between chemical equilibrium and dynamic equilibrium? |
[![Image 1][1]][1]
The following reaction has been taken from my study material. This shows that the benzene ring is undergoing a nucleophilic aromatic substitution via benzyne mechanism (presence of a strong base like $\ce{NaNH2}$). My question is:
**Why is substitution preferred at the ortho position?**
The ... |
I came across this article on wikipedia on ethylene glycol stating that it decomposes fairly quickly. I was under the impression that ethylene glycol was dangerous to let leach into soil, but I think I'm mistaken as [wikipedia][1] states
> it [ethylene glycol] breaks down in air in about 10 days and in water or soi... |
Is chemical equilibrium and dynamic equilibrium the same thing? Both point to the reversible reactions and no net changes in the concentrations of product and reactant.
Dynamic equilibrium from Wikipedia:
In chemistry, and in physics, a dynamic equilibrium exists once a reversible reaction occurs. Substances tran... |
While talking about ionic bonds my book states :
>Higher the value of electron gain enthalpy of the atom, greater the ease of formation of the anion from it, i.e., other atom should have high value of electron gain enthalpy.
Now I think it should say **more negative** than just **higher** (as negative enthalpy me... |
Is chemical equilibrium and dynamic equilibrium the same thing? Both point to the reversible reactions and no net changes in the concentrations of product and reactant.
[Dynamic equilibrium from Wikipedia](https://en.wikipedia.org/wiki/Dynamic_equilibrium):
> In chemistry, and in physics, a dynamic equilibrium ex... |
All of the paths given by the OP can lead to discovery of catalysts. Usually, it is a combination of strategies and an accumulation of knowledge from different sources. I will give two examples, ammonia synthesis and enzymatic reactions.
**Ammonia synthesis**
$$\ce{N2(g) + 3H2(g) <=> 3NH3(g)}$$
The synthesis of ... |
Why is NH3 a stronger base than PH3,AsH3,SbH3,BiH3 and McH3? |
I was given a problem that requires me to synthesize (*1R,2R*)-2-methoxycyclohexanol from cyclohexene. I tried it with *syn*-hydroxylation of alkene $\pi$ bond with $\ce{OsO4}$ and NMO then directly transformed the hydroxyl group to methoxy group with $\ce{NaOH}$ and $\ce{CH3I}$.
During the protonation of one hydrox... |
How to prevent feasibility of intermolecular attack of 1,2-diol? |
Please help!
I was working on a mock research project/lab for my chemistry class testing the rate of electroplating of copper vs. voltage. I had copper and nickel electrodes and .1M copper sulfate solution. I made a huge mistake, however, and plugged the positive end into my nickel electrode and the negative end into ... |
Good day everyone,
I would like to ask how we can see entropy as an intrinsic property of molecules, namely as something depending also on their geometry (and not only as gross disorder). Is this what is called the "shape entropy" or there's no relation between the two concepts? Which are the parameters that determ... |
I would like to ask how we can see entropy as an intrinsic property of molecules, namely as something depending also on their geometry (and not only as gross disorder). Is this what is called the "shape entropy" or there's no relation between the two concepts? Which are the parameters that determine this "geometric" en... |
What is the white power that I have extracted from cinnamon? |
These might be basic question but they are quite confusing to me?
if $Sc^+$ doesn't exists why does $\ce{Ti^2^+}$ exist?
on the similar account why does this trend increases at first( till Mn) and then decreases?
My book just concludes that the general trend is due to increase in $Z_{ef}$ and decrease in effect... |
What is the white powder that I have extracted from cinnamon? |
These might be basic question but they are quite confusing to me?
if $Sc^+$ doesn't exists why does $\ce{Ti^2^+}$ exist?
on the similar account why does this trend increases at first( till Mn) and then decreases?
My book just concludes that the general trend is due to increase in $Z_{ef}$ and decrease in atomic... |
I would like to ask how we can see entropy as an intrinsic property of molecules, namely as something depending also on their geometry (and not only as gross disorder). Is this what is called the "shape entropy" or there's no relation between the two concepts? Which are the parameters that determine this "geometric" or... |
It's a standard question on the atomic emission spectrum.
> An atomic emission spectrum of hydrogen shows three wavelengths: 1875
> nm, 1282 nm, and 1093 nm. Assign this wavelengths to transitions in
> the hydrogen atom.
I understand how to calculate it but from both the answers in mybook and the answer from sl... |
It's a standard question on the atomic emission spectrum.
> An atomic emission spectrum of hydrogen shows three wavelengths: $1875$
> $nm, 1282 nm, and 1093 nm$. Assign this wavelengths to transitions in
> the hydrogen atom.
I understand how to calculate it but from both the answers in mybook and the answer fro... |
It's a standard question on the atomic emission spectrum.
> An atomic emission spectrum of hydrogen shows three wavelengths: $1875$
> $nm, 1282 nm, and 1093 nm$. Assign this wavelengths to transitions in
> the hydrogen atom.
I understand how to calculate it but from both the answers in mybook and the answer fro... |
It's a standard question on the atomic emission spectrum.
> An atomic emission spectrum of hydrogen shows three wavelengths: 1875 nm, 1282 nm, and 1093 nm. Assign this wavelengths to transitions in the hydrogen atom.
I understand how to calculate it, but from both the answers in my book and the [answer from slade... |
I was given a problem of reaction between (2R,3S)-3,4-dimethylpentan-2-ol and $\ce{POCl3}$ and pyridine. I know that $\ce{POCl3}$ will be attacked with hydroxyl group and the hydrogen on hydroxyl will be cleaved with pyridine so the hydroxyl group becomes good leaving group.
The reaction mechanism proceeds on E2 mec... |
Is (2R,3S)-3,4-dimethylpentan-2-ol feasible to be dehydrated with POCl3 and pyridine? |
How can i convert .gjf or .chk file to .wfn file? |
I am a homeschooling parent, so pardon me asking stupid questions.
Everywhere I read, it is said carbon based lifeforms eat carbon and after their death that atom starts a decay.
But what I cannot understand, we dont eat or work with food at atomic levels. Yes, life forms breaks down molecules from food and use th... |
how can carbon dating even work? Its at atomic level! |
I am a homeschooling parent, so pardon me asking stupid questions.
Everywhere I read, it is said carbon based lifeforms eat carbon and after their death that atom starts a decay.
But what I cannot understand, we dont eat or work with food at atomic levels. Yes, life forms breaks down molecules from food and use th... |
I'm a little embarrassed to ask this question at this stage of the climate game but, in searching, I seem to get contradictory answers.
For example, here: https://www.eia.gov/tools/faqs/faq.php?id=73&t=11
we see 215.4 lbs CO2 giving 1 million btu heat. Since 1 million btu = 293 kWh, we end up with 0.735 lbs/kWh.
... |
I'm a little embarrassed to ask this question at this stage of the climate game but, in searching, I seem to get contradictory answers.
For example, here: https://www.eia.gov/tools/faqs/faq.php?id=73&t=11
we see 215.4 lbs CO2 giving 1 million btu heat. Since 1 million btu = 293 kWh, we end up with 0.735 lbs/kWh.
... |
This seems to be a pretty easy problem but I cannot understand why we do not consider the contribution of H+ ions by water ( water dissociates into H+ and OH- ) and only that of HCl when we find the total H+ ion concentration, in the same way both NaCl and HCl contribu... |
This seems to be a pretty easy problem but I cannot understand why we do not consider the contribution of $\ce{H+}$ ions by water (water dissociates into $\ce{H+}$ and $\ce{OH-}$) and only that of $\ce{HCl}$ when we find the total $\ce{H+}$ ion concentration, in the... |
I want to do a PES scan of a radical structure in Gaussian. However, I'm not completely sure how to prepare an input file. I've figured out that charge and multiplicity are 0 and 2. What I don't know is how to indicate where a radical is. Will Gaussian figure it out itself by bonds and electrons count or do I have to i... |
What apparatus is needed to get a balloon full of anhydrous carbon dioxide from solid carbon dioxide? |
"6 grams of cinnamon can contain from to 42 to 189 mg cinnamaldehyde." http://herbpedia.wikidot.com/cinnamaldehyde That's not very much.
"Cinnamon consists of a variety of resinous compounds, including cinnamaldehyde, cinnamate, cinnamic acid, and numerous essential oils." https://www.hindawi.com/journals/ecam/201... |
In determining the solubility constant for Ca(OH)2, how does phenolphthalein end point compare with the methyl orange end points? |
I have seen so many conflicting answers to this question in various places so I wanted to ask it again.
[IUPAC defines a *transition element*](https://goldbook.iupac.org/terms/view/T06456) as
> an element whose atom has a partially filled d sub-shell, or which can give rise to cations with an incomplete d sub-shel... |
Is scandium considered a transition metal? |
For the reaction below:
NH4+ + H2O -> NH3 + H30+
I have the following values from a table to use:
[![enter image description here][1]][1]
[![enter image description here][2]][2]
And in the solution manual they tell me to use the Ka for this reaction. Why is this? Why do we use the Ka for NH3 when it is ... |
So i know that it can never be the first option
I dont think it will be the last option either as i read that it should be ortho substituted biphenyl
So when i look at option 2 and 3 I cant make out which one should be the correct answer.
... |
Which biphenyl is optically active? |
These might be basic question but they are quite confusing to me?
If $\ce{Sc+}$ doesn't exists, why does $\ce{Ti^{2+}}$ exist?
on the similar account why does this trend increases at first( till Mn) and then decreases?
My book just concludes that the general trend is due to increase in $Z_{\mathrm{eff}}$ and de... |
> Which biphenyl is optically active?
> [![1: 3‐iodo‐3'‐nitro‐1,1'‐biphenyl; 2: 2,2'‐dibromo‐6,6'‐diiodo‐1,1'‐biphenyl; 3: 2,2'‐diiodo‐1,1'‐biphenyl; 4: 2,6‐dimethyl‐1,1'‐biphenyl][1]][1]
I know that it can never be **1**. I don't think it will be **4** either as I read that it should be *ortho*-substituted biphe... |
A transition metal can be defined as an element that possesses an incomplete sub-level in one or more of its oxidization states. In the textbook I'm reading, it claims that zinc is not a transition metal because it has a full $d$-sub-level in all its oxidization states.
A quick google reveals that zinc has oxidizati... |
How is $\ce{Zn}$ not a transition metal? |
If water freezes at 32°F, what happens to that newly formed ice at that temperature? Does it start melting as soon as it’s frozen, or does it require more heat to melt again? If it does require more heat to melt, then how much? And what would happen if you were in between that melting point and the water’s freezing tem... |
If water freezes at 32°F (0°C) (at sea level), then what temperature does ice melt? |
So what i know is that when we rotate a fisher projection by 180° then we get identical compounds
Going with that i think the option 1 should be correct but in the key the option 4 is given as correct. How is that so?
Also is there any trick... |
Which of the following are identical? |
Snow in winter below 0°C, still sublimed very slowly over time. If I’m not mistaken, sublimation is an endothermic process. Where is this absorbed energy coming from when the surrounding temperature is below 0°C? |
Why does snow sublime even when the surrounding temperature is below 0°C? |
How is Zn not a transition metal? |
My textbook(NCERT) says:
> With exception of $\ce{Fe2(CO)9}$, all other metal carbonyls are soluble in hydrocarbon solvents.
*Weller, M.; Overton, T.; Rourke, J.; Armstrong, F. Inorganic Chemistry, 6th ed.* states:
> The most striking exception among the common metal carbonyls is nonacarbonyl diiron(0), which ... |
Recently I was taught how Aluminium is commercially extracted. The ore is first concentrated by leaching either by Baeyer's process for red bauxite(impurity-Fe2O3) or by Serpeck's process for white bauxite(impurity-SiO2).
Then alumina is reduced electrolytically via Hall-Heroult's process directly to 99% pure Al. B... |
Snow in winter below 0 °C, still sublimed very slowly over time. If I’m not mistaken, sublimation is an endothermic process. Where is this absorbed energy coming from when the surrounding temperature is below 0 °C? |
Why does snow sublime even when the surrounding temperature is below 0 °C? |
Recently I was taught how aluminium is commercially extracted. The ore is first concentrated by leaching either by Bayer's process for red bauxite (impurity: $\ce{Fe2O3}$) or by Serpeck's process for white bauxite (impurity: $\ce{SiO2}$).
Then alumina is reduced electrolytically via Hall–Héroult's process directly ... |
If water freezes at 32 °F, what happens to that newly formed ice at that temperature? Does it start melting as soon as it’s frozen, or does it require more heat to melt again? If it does require more heat to melt, then how much?
And what would happen if you were in between that melting point and the water’s freezing... |
If water freezes at 32 °F (0 °C) at sea level, then what temperature does ice melt? |
If I'm not wrong, I learned in 2011 introduction to neuropsychology course that all enzymes are proteins.
If the current smallest known proteins are of the TAL family (transcription activator-like) of 11 aminco acids,<br>
and if [bromelain][1] is an enzyme which is larger than TAL proteins,
**How come bromelain ... |
If I'm not wrong, I learned in 2011 introduction to neuropsychology course that all enzymes are proteins.
As far as I know, any protein, not even the smallest of the [TAL group][1] (which I understand to be the smallest currently known protein group), can be represented on a common-size two dimensional diagram (say,... |
If yes, could you please cite the source for it and the value? |
Does anybody have the literature value for the activation energy of the reaction between hydrocholoric acid and sodium bicarbonate? |
I know about [ACD/Spectrus Processor](https://www.acdlabs.com/products/adh/spectrusprocessor) which is a software platform to integrate analytical chemistry data from multiple mass spectrometer device vendors (e.g. Agilent Technologies, Bruker, Waters) to allow data processing. Are there comparable software platforms o... |
Software platforms with integration of multi vendor mass spectrometer device data? |
I know this question might be too basic for this site, but i really need helps. I begin studying organic chemistry and i thought i was lost somehow. My question is : Why is in the substitution with cyanide ions, we use KCN ? Why don't we use something like NaCN, HCN, etc? I don't understand why it is. |
So what i know is that when we rotate a fisher projection by 180° then we get identical compounds ( I might be wrong)
But how to tell if the compounds are enantiomers of each other or not.
For that how to get the same group i.e -cooh in... |
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