instruction stringlengths 15 21.8k |
|---|
I am attempting to perform a Grignard reaction involving methyl 3-butenoate and methyl magnesium iodide in order to yield the unsaturated tertiary alcohol 2-methyl-4-penten-2-ol. The issue in doing this is that conditions are involved in the acidic workup of the bromomagnesium alkoxide the would also result in the acid... |
We have a reaction
$$
2N_2O_5 \rightarrow 4NO_2 + O_2
$$
which has a rate constant $k=6,2\cdot10^{-4}/\mathrm{min}$ at temperature $T=318.15\ \mathrm{K}$. How much oxygen is formed in litres when $1.00\ \mathrm{mol}$ of $N_2O_5$ is at $318.15\ \mathrm{K}$ in $104\ \mathrm{kPa}$ pressure for $20$ hours. Correct ans... |
How much oxygen is formed in this First Order Reaction? |
If the neutralization between strong acid and bases has enthalpy of neutralization of around $\pu{-57.1 kJ mol^-1}$, why is it that when I try to calculate the enthalpy of formation of water from $\ce{H+}$ and $\ce{OH-}$ ions I get approximately $\pu{-55.8 kJ mol^-1}$ using the reference values?
Why is there this d... |
Are monosubstituted cyclopropanes achiral or chiral? |
When water boils and you suddenly shut the heat off, a lot of steam arises from it just after you shut the heat off. Why this happens, I thought that maybe water condenzes very fast in small droplets so they get flown up? |
I understand that in large quantities the reaction is explosive but couldn't the flow of gas just be regulated to control the reaction? It seems like producing hydrogen chloride like this then dissolving it would be a very straightforward way to make hydrochloric acid.
To clarify, when I say 'typically' I mean o... |
Why isn't hydrochloric acid typically made via the photochlorination of hydrogen? |
According to IUPAC only physical quantities and variables must be italicised.
https://iupac.org/wp-content/uploads/2016/01/ICTNS-On-the-use-of-italic-and-roman-fonts-for-symbols-in-scientific-text.pdf states that 'a good general rule is that quantities, or variables, can be given a value, but labels cannot'.
So ... |
How is the rate of adsorption related to the critical temperature of a gas? My textbook says more the critical temperature, better are they adsorbed. But I cannot really understand why. They threw in another confusing statement that says that easily liquefiable gases are readily adsorbed. I am thoroughly confused.
I... |
I notice that saliva seems to clean well, much better than plain water. For example, tar spots on the car can be difficult to get off. I typically use really powerful solvents to get them off, like 95% acetone and things like that. Yet, saliva works too.
Why is this? |
Why does saliva clean so well? |
Synthesis of silver nanoparticles by electrochemical Method
[![enter image description here][1]][1]
The silver content in these products consists of both silver ions and silver particles. Typically 90% of silver content is in the form of ionic silver and the remaining 10% of the silver content is in the form of ... |
While oil and fossil fuel are dense in energy. I have known only one way to retrieve energy from it, which is burn it. I wish it should have some way we could have a way to get energy from it without moving parts
Are there any way we could get energy from oil, gas, diesel, etc. without burning it? So we could making... |
Are there any chemical pathway or catalyst that could produce electricity from fossil fuel without combustion? |
It is a common fact that Cl2 reacts to form HCl and HOCl when dissolved in water. However, how exactly does the reaction proceed?
The first step could either be that the oxygen atom in H2O attacks Cl2, forming Cl- and H2OCl+, which then loses a proton to become HOCl.
But it could also be that chlorine attacks the H i... |
It is a common fact that $\ce{Cl2}$ reacts to form $\ce{HCl}$ and $\ce{HOCl}$ when dissolved in water. However, how exactly does the reaction proceed?
The first step could either be that the oxygen atom in $\ce{H2O}$ attacks $\ce{Cl2}$, forming $\ce{Cl-}$, and $\ce{H2OCl+}$, which then loses a proton to become $\ce{HO... |
I have seen in many books wherein dehydration reactions are carried out using Al2O3. But I don't understand how Al2O3 acts as a dehydrating agent.
Is there any mechanism involved in it? |
According to IUPAC, only physical quantities and variables must be italicised.
[*Section 8 Use of Italic and Roman Fonts for Symbols in Scientific Text* of ICTNS Guidelines for Drafting IUPAC Technical Reports and Recommendations](https://iupac.org/wp-content/uploads/2016/01/ICTNS-On-the-use-of-italic-and-roman-f... |
For my electrochemistry lab I'm using $\pu{10 mL}$ of $\ce{ZnSO4}$ and $\pu{10 mL}$ of $\ce{CuSO4}$ solutions connected with a salt bridge. I connect $\ce{Zn}$ metal and $\ce{Cu}$ metal to a voltmeter and dip those metals in the correct beakers. The voltage I get is $\pu{1.044 V}.$
However when I add $\pu{10 mL}$ of... |
Does the concentration affect the voltage in electrochemistry? |
We have a reaction
$$\ce{2N2O5 -> 4NO2 + O2},$$
which has a rate constant $k=6,2\cdot10^{-4}/\mathrm{min}$ at temperature $T=318.15\ \mathrm{K}$. How much oxygen is formed in litres when $1.00\ \mathrm{mol}$ of $\ce{N2O5}$ is at $318.15\ \mathrm{K}$ in $104\ \mathrm{kPa}$ pressure for $20$ hours. Correct answer: $6.... |
How much oxygen is formed in this first order reaction? |
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/pxdHw.jpg
Hello.
I read about different methods how to clean this specific(attached photo)pocket pH meter before storage and i can't figure out what is the right way.
One method says to stir the pH meter(glass electrode)in distilled ... |
How to clean pocket pH meter before storage? |
[![enter image description here][1]][1]
Hello.
I read about different methods how to clean this specific(attached photo)pocket pH meter before storage and i can't figure out what is the right way.
One method says to stir the pH meter(glass electrode)in distilled water and
replace the protective cap,other says t... |
what is cyclopropane's reaction with lithium aluminium hydride? I think it must lead to ring-opening but I didn't find any article favoring this in my texts. |
On the one hand it is stated that reversible processes cannot occur, as they are infinitely slow.
On the other hand phase transitions are said to be reversible processes? |
As phase transitions are considered reversible processes, shouldn't they be non-spontaneous? |
When considering Fusion, the matter that gets converted into energy what specific matter is converted exactly like a quark and is most of the energy created from the matter turning into energy? |
I have gone through a simple idea that proteins have different conformations; it is a dynamic system. Moreover, whenever we do ensemble experiments, so we get an average picture. There are some questions-:
Q.1 Often protein structures are reported in PDB (protein data bank), so what do they signify? The most stable ... |
What do X-ray diffraction and NMR tell about the Proteins? |
I am assuming that the -I inductive effect in 2,3-dinitrophenol is stronger than in 2,4-dinitrophenol since it operates through less bonds, therefore on inductive grounds it should have a lower pKa?
However I am unclear whether there are any differences in π-resonance effects. Any help?
|
How does the relative acidity of 2,3-dinitrophenol compare to that of 2,4-dinitrophenol? |
I searched for the answer for this question on Wikipedia and Stackexchange a lot but couldn't find same question or a required answer in some other similar question.
I understand that the function of the salt bridge is to complete the circuit and maintain electrical neutrality in both the half cells of a galvanic ... |
Does the salt bridge in a galvanic cell deplete over time? |
I have gone through a simple idea that proteins have different conformations; it is a dynamic system. Moreover, whenever we do ensemble experiments, so we get an average picture. There are some questions-:
Q.1 Often protein structures are reported in PDB (protein data bank), so what do they signify? The most stable ... |
how can I measure the pH of a HF:H2O:CH3OH solution? more specifically, how can I precisely and accurately measure the H+ ion concentration? |
how can I measure the pH of a HF:H2O:CH3OH solution? |
Dynamics can mean many things, and not all proteins undergo extensive conformational changes during their lifetime. Some are fairly rigid in solution.
XRD or NMR data represents a temporal average over the conformations of a protein construct sampled under the experimental conditions. A protein construct is a varia... |
I am assuming that the -I inductive effect in 2,3-dinitrophenol is stronger than in 2,4-dinitrophenol since it operates through less bonds, therefore on inductive grounds it should have a lower pKa?
However it's unclear to me whether there are any differences in π-resonance effects. Any help?
|
One standard definition of equilibrium in beginner chemistry is that for a reversible reaction, (dynamic) equilibrium has been achieved when the rate of the forward and backward reactions are equal. We also define the equilibrium constant for a given reaction in terms of a ratio involving the concentrations of products... |
I am doing an experiment on how pH buffers may affect amylase's break down of starch into glucose in a starch solution. I am using iodine reagent to identify how much starch is left after amylase is added. I am wondering, to which wavelength should I set the spectrophotometer to in order to measure the absorbance and p... |
what wavelength should I use to measure the transmittance of iodine colouring? |
According to my textbook, the reaction between $\ce{NOCl}$ and $\ce{R-NH2}$ is as follows:
[![][1]][1]
[1]: https://i.stack.imgur.com/O7dmd.jpg
But how exactly does the reaction proceed?
The first step (what I think) could be that $\ce{NOCl}$ dissociates into $\ce{NO+}$ and $\ce{Cl-}$ ions and then the ... |
According to my textbook, the reaction between $\ce{NOCl}$ and $\ce{R-NH2}$ is as follows:
> $$\ce{R-NH2 + NOCl -> RCl + N2 + H2O}$$
But how exactly does the reaction proceed?
The first step (what I think) could be that $\ce{NOCl}$ dissociates into $\ce{NO+}$ and $\ce{Cl-}$ ions and then the $\ce{Cl-}$ ion at... |
At the molecular level, I would like to know fundamentally how does a vitamin differs from a mineral. I understand both have, to say, Fe (Iron), then what exactly makes it a mineral Iron or a vitamin Iron. Does the properties of Iron changes from Vitamins to minerals? |
I am assuming that the -I inductive effect in 2,3-dinitrophenol is stronger than in 2,4-dinitrophenol since it operates through less bonds, therefore on inductive grounds it should have a lower $\mathrm{p}K_\mathrm{a}$?
However it's unclear to me whether there are any differences in π-resonance effects. Any help?
|
Why would the chloride ion attack the electron rich amine? The amine is the best nucleophile is the system and will attack the NO+. This gives a RNH-NO nitroso species which is then protonated on Oxygen, loses water and gives the diazonium cation. This adds loses nitrogen rapidly and adds Chloride to give the primary a... |
Dynamics can mean many things, and not all proteins undergo extensive conformational changes during their lifetime. Some are fairly rigid in solution.
XRD or NMR data represents an average over the conformations of a protein construct sampled under experimental conditions. A protein construct is a variant of the pr... |
[![enter image description here][1]][1]
Can anyone suggest a probable reason for this conversion? This seems like a simple conversion from hemiaminal to imine.
For secondary amine this kind of conversion might be possible by [![enter image description here][2]][2]
[1]: https://i.stack.imgur.com/SPsVF.png
... |
Can anyone suggest a mechanism for hemiaminal metal complex to imine complex? |
So in the following article
http://www.dynamicscience.com.au/tester/solutions1/chemistry/equilibrium/summarylechats.html
In this reaction, the forward reaction is exothermic while the reverse reaction is endothermic.
N2(g) + 3H2(g) <=> 2NH3(g) ΔH = -92 kJ/mol
If the forward reaction is exothermic, increasing ... |
[![enter image description here][1]][1]
Can anyone suggest a probable reason for this conversion? This seems like a simple conversion from hemiaminal to imine.
For secondary amine this kind of conversion might be possible by [![enter image description here][2]][2]
[1]: https://i.stack.imgur.com/SPsVF.png
... |
What is the product when phenol reacts with conc. $\ce{H2SO4}$ in excess?
I have been told that the major product will be *ortho* at low temperature and *para* at high temperature. Why cannot it form both *ortho-* and *para*-substituted product as in the case of picric acid?
|
Could someone please help me with the following question.
Due to the perspective of voids in the MgO structure, what is the maximal amount of Sr that can substitute with Mg.
And why is it unlikely that it will happen? |
According to the article [*Summary of Le Chatelier's Principle* on dynamicscience.com.au](http://www.dynamicscience.com.au/tester/solutions1/chemistry/equilibrium/summarylechats.html), for the process
> $$\ce{N2(g) + 3 H2(g) <=> 2 NH3(g)}\quad ΔH = \pu{-92 kJ/mol}$$
the forward reaction is exothermic, while the r... |
Could someone please help me with the following question.
Due to the perspective of voids in the MgO structure, what is the maximal amount of Sr that can substitute with Mg.
And why is it unlikely that it will happen?
Since the quota between the radiis is 0.84 and the size of the octahedral void is 0.414 the at... |
> Shouldn't it clearly be the opposite, as increasing temperature favors the reverse reaction?
Yes, they made a mistake. For all the other scenarios, they paired a figure of the rate changes with a figure of the matching concentration changes. For this scenario (increase in temperature) they matched it with a correc... |
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/ZMSPk.png
This reaction isn't going by changing the time or temperature conditions. So, I added some (0.5 equivalent) triflic acid to increase the electrophilicity of the carbonyl. The reaction is proceeding but conversion isn't high. Is tri... |
How to increase the conversion for the reaction between 2-acetylpyridine and diamine? |
> Shouldn't it clearly be the opposite, as increasing temperature favors the reverse reaction?
Yes, they made a mistake. For all the other scenarios, they paired a figure of the rate changes with a figure of the matching concentration changes. For this scenario (increase in temperature) they matched it with a correc... |
This picture is from https://chemistry.stackexchange.com/questions/68859/how-are-the-number-of-tetrahedral-voids-twice-the-number-of-octahedral-voids-in:
[![enter image description here][1]][1]
Let's say the red circles represent a layer of atoms above, and the pink circles a layer of atoms below. The T's and O's... |
I don't understand why nitrogen dioxide $\ce{NO2}$ is coloured brown when nitrate $\ce{NO2-}$ and dinitrogen tetroxide $\ce{N2O4}$ are not. I understand it is due to absorption of light when its frequency matches the energy of an electronic transition. But what makes $\ce{NO2}$ special, i.e. what electronic transition ... |
I know HPLC is a form of column chromatography that uses high pressure to pump a sample mixture/eluent through a column. However, I'm not sure if this technique is being used to purify and isolate organic products? After doing some research, I found that automated flash chromatography systems use LPLC technique rather ... |
Can we use HPLC to purify an organic reaction product? |
This picture is from https://chemistry.stackexchange.com/questions/68859/how-are-the-number-of-tetrahedral-voids-twice-the-number-of-octahedral-voids-in:
[![enter image description here][1]][1]
Let's say the red circles represent a layer of atoms above, and the pink circles a layer of atoms below. The T's and O's... |
[![enter image description here][1]][1]
It is given that the above statement is **false**. Why does o-nitrophenol, in spite of intramolecular hydrogen bonding, have a lower pKa than o-chlorophenol?
[1]: https://i.stack.imgur.com/1bRjI.png |
[![o-nitrophenol vs. o-chlorophenol][1]][1]
It is given that the above statement is **false**. Why does *o*-nitrophenol, in spite of intramolecular hydrogen bonding, have a lower $\mathrm{p}K_\mathrm{a}$ than *o*-chlorophenol?
[1]: https://i.stack.imgur.com/1bRjI.png |
[![o-nitrophenol vs. o-chlorophenol][1]][1]
It is given that the above statement is **true**. Why does *o*-nitrophenol, in spite of intramolecular hydrogen bonding, have a lower $\mathrm{p}K_\mathrm{a}$ than *o*-chlorophenol?
[1]: https://i.stack.imgur.com/1bRjI.png |
The thing you have to realise is that H-bonding can *lower* the ease with which the acidic H is removed, but it does not render it completely 'locked' within the molecule. What you have to understand is, the hydrogen bond shown here is not **that** strong as compared to the other kinds of H-bonds which have been observ... |
The thing you have to realise is that H-bonding can *lower* the ease with which the acidic H is removed, but it does not render it completely 'locked' within the molecule. What you have to understand is, the hydrogen bond shown here is not **that** strong as compared to the other kinds of H-bonds which have been observ... |
I understand the procedure but not the questions. The strange thing is that the problem is over-determined: I can calculate the amount of HCl not neutralized by calcium carbonate either by looking at the amounts of the two (assuming the reaction goes to completion) or by the titration (assuming that neutralizing means ... |
I understand the procedure but not the questions. So there are two reactions:
$$\ce{2HCl(aq) + CaCO3(s) -> H2CO3(aq) + 2 Cl-(aq) + Ca2+(aq)}$$
$$\ce{HCl(aq) + NaOH(aq) -> H2O(l) + Cl-(aq) + Na+(aq)}$$
The first reaction has reactants in non-stoichiometric amounts. The second reaction, a titration, is done with s... |
My answer starts with the premise that a static equilibrium exists (although that is debatable).
> How could we be sure that one certain reaction in equilibrium is dynamic?
If your reaction is at dynamic equilibrium, changing the temperature or the concentration of one of the reactant or product species (by addin... |
> A compound has $67.3 \% \rm~C,4.62 \%~N,6.93 \%~ H$ and O. Determine the molecular formula of the compound knowing its molar mass is $283\rm~\frac{g}{mol}$.
My solution : The percentage for the oxygen is $$100-( 67.3+4.62+6.93)=21.15$$ percent oxygen. Lets determine the number of moles for every substance.
Fo... |
Rather than starting out with 100 g of unknown, I would start out with 1 mol of unknown, i.e. 283 g. That way, you can directly calculate how many moles of each element are in one mole of compound:
$$ n = 67.3 \% \cdot \frac{\pu{283 g}}{\pu{12 g mol-1}} = \pu{15.86 mol}$$
Or to get the stoichiometric coefficient... |
The thing you have to realise is that H-bonding can *lower* the ease with which the acidic $\ce{H}$ is removed, but it does not render it completely 'locked' within the molecule. What you have to understand is, the hydrogen bond shown here is not **that** strong as compared to the other kinds of H-bonds which have been... |
This touches on how smell works, but my intent is ask about the mechanism for why do ionised smell like they do? I would like to get one step past ozone if that is the primary mechanism. |
what causes the smell of a room ionizer? If ozone, what are we actually smelling when ozone interacts with nasal mucous? |
I wanted to ask a question about the kinetics of an oxidation reaction using Chromium reagents.
I was given a lecture today on the mechanism of alcohol oxidations using Chromate (VI) reagents:
[![enter image description here][1]][1]
My previous [knowledge][2] of Rate-Determining steps (RDS) were that on an ... |
Let me crash the party here.
**TL;DR: Dispersion interactions are *not* due to fluctuating induced-dipole attractions, even if everyone tries to explain it that way.**
(I know that this must seem like an outrageous statement, and surely downvote fingers are itching now. Bear with me.)
Based on the [Hellmann-Fe... |
Let me crash the party here.
**TL;DR: Dispersion interactions are *not* due to fluctuating induced-dipole attractions, even if everyone tries to explain it that way.**
(I know that this must seem like an outrageous statement, and surely downvote fingers are itching now. Bear with me.)
Based on the [Hellmann-Fe... |
> A compound has $67.3 \% \rm~C,4.62 \%~N,6.93 \%~ H$ and O. Determine the molecular formula of the compound knowing its molar mass is $283\rm~\frac{g}{mol}$.
My solution : The percentage for the oxygen is $$100-( 67.3+4.62+6.93)=21.15$$ percent oxygen. Lets determine the number of moles for every substance.
Fo... |
I am supposed to synthesize tripeptide Ala-Asn-Phe using Merrifield... So I:
1. attached protected Phe as the first amino acid
2. got rid of protecting group (BOC)
3. added asparagine with 2 protecting groups - BOC for alpha NH2 group and FMOC for the gamma NH2 group
4. got rid of BOC and added Ala protected wit... |
I am supposed to synthesize tripeptide, $\mathrm{Ala-Asn-Phe}$, using Merrifield peptide synthesis procedure. Accordingly, I have done followings:
1. Attached protected $\mathrm{Phe}$ as the first amino acid.
2. Got rid of protecting group ($\mathrm{BOC}$)
3. Added asparagine with 2 protecting groups - $\mathrm{B... |
I am reading an introductory textbook on electronics: *Practical Electronics for Inventors* by Paul Scherz and Simon Monk. In a section discussing the motion of electrons in circuits, the textbook mentions something called *free electron-bond electron interactions*:
> It is likely that those electrons farther "down ... |
I'm studying about the s-block elements in my course of Inorganic Chemistry and I happened to come across the following text.
> Electrons may be quite readily excited to a higher energy level, for example in the flame test. To perform this test, a sample of **Metal Chloride** or any salt of metal moistened with conc. ... |
Let's say I have a 50 lb CO2 tank which can probably contain about 1000 L of the gas at 122 atm. Suppose I want to use the tank to fill a 0.5 L plastic bottle which only has air in it.
We know that gases always assume the shape and volume of their container. If that is true then that would mean that I can transfer t... |
How much CO2 can I fit in a 0.5 L plastic bottle? |
Can we obtain information regarding the interactions between different molecules, their excess molar volumes using the radial distribution functions?
If I obtain the radial distribution function of the Nitrogen atom in pure acetonitrile and then in a mixture of acetonitrile and some other substance. Can I correlate ... |
Can we relate the interaction between species using the radial distribution function? |
I'm trying to study the [Tea leaf paradox][1], and asked a [question][2] about it on physics.stackexchange.com. To get further on the problem, I want to make a solution of very small objects in water that are distinguishable to the naked eye, and have (very close to) neutral buoyancy. I teach at a high school and have ... |
So I was reading about impurities of in water and I have a question in mind:
So say we have Distilled Water , Deionized Water , Tap Water and Soft water which was softening using dowex resin or any other cation exchange resin.
So my question is which samples would contain anions like $Cl^-$ and $PO_4^-$ and which... |
What is the black graphite looking slag that is formed when sterling silver is melted with borax? Is there a way to remove it from the surface of the sterling silver? It appears to be indestructible!
The melting is related to jewelry casting. All melting was done in an electric Ney muffle furnace. Here is a melt... |
What is the black slag formed when sterling silver is melted with borax? |
It's plastic shaker cups, they came with instructions saying they are not dishwasher safe but they did not deform in the dishwasher. Does this mean it's probably unsafe to clean them using the dishwasher due to stressing the plastic, unleashing chemicals?
Thinking of the study showing additives in PP5 plastic had est... |
PP05 plastic "not dishwasher safe" but does not deform? Leaching chemicals? |
Can **butan-1-ol** be written as **butanol**, and is it connected to **butan-1-ol** having Isomers? |
Can butan-1-ol be written as butanol, and is it connected to butan-1-ol having Isomers? |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.