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Are all tetramers considered to be "dimers of dimers"? |
Are polar bond stronger than non-polar bonds? |
In the test for Cl<sup>-</sup> the chloride ions are converted into AgCl by the following reaction,
Cl<sup>-</sup> + AgNO<sub>3</sub>
→
NO<sub>3</sub><sup>-</sup> + AgCl
which is then dissolved in ammonium hydroxide by the formation of diammine silver chloride by the following reaction:
AgCl + 2NH<su... |
Aluminium oxide: $\ce{4Al + 2O_2 = 2Al2O3} \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, (\ce{\Delta H_f = -1675 kJ/mol})$
Magnesium oxide: $\ce{2Mg + O_2 = 2MgO} \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, (\ce{\Delta H_f = -602 kJ/mol})$
Iron (III) oxide: $\ce{4Fe + 3O_2 = 2Fe2O3} \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\... |
Why is the standard enthalpy of formation of aluminium oxide higher than magnesium oxide? |
I experimentally obtained the activation energy of a reaction to be approximately 101kJ/mol. I was then going to use the value for the activation energy to see how the number of particles with sufficient energy to undergo a successful reaction changes with temperature using the Maxwell-Boltzmann energy distribution. Ho... |
Will a sulfur piercing tarnish if submerged in sulfur water (hot spring)? |
Will a titanium piercing tarnish if submerged in sulfur water (hot spring)? |
Because you are comparing apples with donuts. If I eat enough apples they will add more calories than that donut I gobbled for breakfast.
To compare food calories properly you need to match serving sizes. Similarly, to compare reaction energies fairly you need to use a common basis for the extent of reaction. For... |
In electrochemistry, I know that standard emf of a cell (also called standard electrode potential (E°)) is an intensive property.
But, I wanted to know whether non-standard emf will also be intensive or extensive?
(Also, in general, is electromotive force intensive or extensive?) (I mean emf used in other topics ... |
Because you are comparing apples with donuts. If I eat enough apples they will add more calories than that donut I gobbled for breakfast.
To compare food calories properly you need to match serving sizes. Similarly, to compare reaction energies fairly you need to use a common basis for the extent of reaction. For... |
$$\begin{align}
&\text{Aluminium oxide:} &\ce{4Al + 2O_2 &-> 2Al2O3} &(\Delta H_\mathrm f &= \pu{-1675 kJ/mol})\\[1.5em]
&\text{Magnesium oxide:} &\ce{2Mg + O_2 &-> 2MgO} &(\Delta H_\mathrm f &= \pu{-602 kJ/mol})\\[1.5em]
&\text{Iron (III) oxide:} &\ce{4Fe + 3O_2 &-> 2Fe2O3} &(\Delta H_\mathrm f &= \pu{-824 kJ/mol})... |
Consider the following rxns:
$$\begin{align}\ce{C + O2&->CO2}\tag{1}\\[1em]
\ce{2C + O2&->2CO}\tag{2}\\[1em]
\ce{2CO + O2&->2CO2}\tag{3}\\[1.5em]
[(2)+(3)]/2 &= (1)\end{align}$$
[![Ellingham Diagram for Carbon][1]][1]
Since $G$ is a state function, why aren't the straight lines corresponding to these reacti... |
$$\begin{align}
&\text{Aluminium oxide:} &\ce{4Al + 3O_2 &-> 2Al2O3} &(\Delta H_\mathrm f &= \pu{-1675 kJ/mol})\\[1.5em]
&\text{Magnesium oxide:} &\ce{2Mg + O_2 &-> 2MgO} &(\Delta H_\mathrm f &= \pu{-602 kJ/mol})\\[1.5em]
&\text{Iron (III) oxide:} &\ce{4Fe + 3O_2 &-> 2Fe2O3} &(\Delta H_\mathrm f &= \pu{-824 kJ/mol})... |
We all know how CO2, as a greenhouse gas affects the climate and causes global warming. I was thinking of a small device, which could be attached to the exhaust pipe of an automobile. It could convert the CO2 into something having negligible greenhouse effect, such as water. Is this feasible? Thanks! |
Actually, the mechanism of $\ce{Ag3N}$ creation (and also the associated Silver amide, $\ce{AgNH2}$, and the imide $\ce{Ag2NH}$) has not been definitely accounted for, either by accident investigation reports or per a recent review of the literature, on possible paths to explosive Silver nitride.
I have ideas of a... |
Actually, the mechanism of $\ce{Ag3N}$ creation (and also the associated products, Silver amide $\ce{AgNH2}$, and the imide $\ce{Ag2NH}$), have not been definitely accounted for, either by accident investigation reports or per a recent review of the literature, on possible paths to explosive Silver nitride.
I have ... |
Actually, the mechanism of $\ce{Ag3N}$ creation (and also the associated products, Silver amide $\ce{AgNH2}$, and the imide $\ce{Ag2NH}$), have not been definitely accounted for, either by accident investigation reports or per a recent review of the literature, on possible paths to explosive Silver nitride.
I have ... |
The $\ce{CO}$ triple bond has a bond enthalpy of 1072 kJ/mol while the $\ce{N2}$ triple bond has a bond enthalpy of 945 kJ/mol, at least according to my source. The molecules are isoelectronic, so I couldn't think of any way to explain it using MO theory. I've read many explanations that did not make much sense, includ... |
Actually, the mechanism of $\ce{Ag3N}$ creation (and also the associated products, Silver amide $\ce{AgNH2}$, and the imide $\ce{Ag2NH}$), have not been definitely accounted for, either by accident investigation reports or per a recent review of the literature, on possible paths to explosive Silver nitride.
I have ... |
Are all protein tetramers considered to be "dimers of dimers"? |
**How strong is the "hydrophobic force"?**\
\
Hydrophobic interactions are weak interactions but have a greater strength than hydrogen bonds. I find the strength of the hydrogen bond in literature to be near 1 pN. Finding the strength of the hydrophobic bond has proven to be a bit more elusive. I would guess that the... |
**How strong is the "hydrophobic force"?**\
\
Hydrophobic interactions are weak interactions but can have greater strength than hydrogen bonds. I find the strength of the hydrogen bond in literature to be near 1 pN. Finding the strength of the "hydrophobic bond" has proven to be a bit more elusive. I would guess that... |
> Both water and ethanol are colourless. How can I observe that they are infinitely soluble ?
They have different refractive index. You will see Schlieren as you mix them, which will eventually disappear. If two solutions don’t mix, there will be a visible interface. If you have trouble seeing it, mix it and let it ... |
In a reaction between an aliphatic primary amine and a ketone, I could expect a ketimine as a product or intermediate. My question regards tautomerization of this intermediate: has tautomerization between the two possible imine structures ever been observed, or is even possible? I tried to search imine tautomerism and ... |
**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... |
Is my solution correct? |
Consider the following reactions:
$$\begin{align}\ce{C + O2&->CO2}\tag{1}\\[1em]
\ce{2C + O2&->2CO}\tag{2}\\[1em]
\ce{2CO + O2&->2CO2}\tag{3}\\[1.5em]
[(2)+(3)]/2 &= (1)\end{align}$$
[![Ellingham Diagram for Carbon][1]][1]
Since $G$ is a state function, why aren't the straight lines corresponding to these r... |
how can i solve this problem? What mathemathical mistake do i have? |
how can i solve this problem? What mathemathical mistake do i have? |
What hydrocarbons burn in air without a change in volume? |
In a reaction between an aliphatic primary amine and a ketone, I could expect a ketimine as a product or intermediate. My question regards tautomerization of this intermediate: has tautomerization between the two possible imine structures ever been observed, or is even possible? I tried to search imine tautomerism and ... |
Is tautomerism in ketimines possible? |
I was looking at the table of bond energies, and what caught my eye was how the bond energy for a C=O bond is 736kJ/mol with the exception of the C=O bonds in CO2 being 799kJ/mol.
What causes CO2 to make such a big difference in a C=O bond?
[![][1]][1]
[1]: https://i.stack.imgur.com/ZrXbJ.png |
Why is the bond energy for a C=O bond higher in CO2? |
I was reading the [Lab Manual](https://ncert.nic.in/pdf/publication/sciencelaboratorymanuals/classXI/chemistry/kelm207.pdf) for Chemistry prepared by the [NCERT](https://en.wikipedia.org/wiki/National_Council_of_Educational_Research_and_Training) . While going through the the test for Chloride ions (pg 88) I came acros... |
I'm trying to synthesize [![this molecule][1]][1] from cyclohexanone, i thought about LDA then adding an R group that has a ketone but is that possible, as far as i know we can add halogen or alkyl chain only, if it's not possible how can I get this compound from cyclohexanone?
[1]: https://i.stack.imgur.com/p0NkT... |
Is it possible to add R chain that contains a carbonyl (ketone) to the alpha carbon? |
I'm trying to synthesize 2‐(3‐oxobutyl)cyclohexan‐1‐one from cyclohexanone:
[![2‐(3‐oxobutyl)cyclohexan‐1‐one][1]][1]
I thought about LDA, then adding an R group that has a ketone. Is that possible? As far as I know, we can add halogen or alkyl chain only. If it's not possible how can I get this compound from c... |
Why does vapor pressure of ice decrease faster than water when temperature decreases? |
**I found this problem:**
We have the following reversible reaction: $A \ce{<=>[\ce{k_1}][\ce{k_2}]} B $, described by the kinetics equation:
$$\frac{d[X]}{dt} = k_1([A]_0-[X])-k_2([B]_0+[X])$$
**Where**
$[X]$ is the increase of molar concentration;
$[A]_0$ and $[B]_0$ are the initial concentrations of $A$ and... |
Reversible equation in Chemical Kinetics — Should I use definite integral when solving the differential equation? |
I know for sure that if you fill a balloon with water (without leaving any air inside) and you start heating it, the balloon won't expand until the temperature reaches 100 °C.
I think it is because while the temperature is below 100 °C, the vapor pressure of the liquid is <760 mmHg so any expansion of the balloon is p... |
Why doesn't water evaporate in a balloon filled with water? |
I was looking at the table of bond energies, and what caught my eye was how the bond energy for a $\ce{C=O}$ bond is 736 kJ/mol with the exception of the $\ce{C=O}$ bonds in $\ce{CO2}$ being 799 kJ/mol.
What causes $\ce{CO2}$ to make such a big difference in a $\ce{C=O}$ bond?
[![][1]][1]
[1]: https://i.sta... |
I was looking at the table of bond energies, and what caught my eye was how the bond energy for a $\ce{C=O}$ bond is $\pu{736 kJ/mol}$ with the exception of the $\ce{C=O}$ bonds in $\ce{CO2}$ being $\pu{799 kJ/mol}$.
What causes $\ce{CO2}$ to make such a big difference in a $\ce{C=O}$ bond?
[![Bond energies][1]]... |
If we look at the character table of NH3 we see that these are the symmetry elements {E, 2 C3, 3 sigma v} present in the molecule. My question is - why are there 2 C3 rotation axes? Shouldn't there be only one which is present perpendicular to the plane consisting of 3 H's? |
If we look at the character table of NH3 we see that these are the symmetry elements {E, 2 C3, 3 sigma v} present in the molecule. My question is - why are there 2 C3 rotation axes? Shouldn't there be only one which is present perpendicular to the plane consisting of 3 H's?
[![enter image description here][1]][1]
... |
Which acetate salt is blue and turns yellow when dissolved in water? |
Why do we need weak or strong acids to displace the anions of other weak acids from salts? |
I’m not sure if this is a stupid question or not, but since bonds are not physically there as such, what does it mean when it can rotate? And how do pi bonds prevent rotation if they are not physical? |
If bonds are not physical things, what is meant by bond rotation? |
Well, the question is short. Can lewis acids and bases change the colour of a litmus paper? I can't seem to find the answer online (at least according to my high school level chemistry search history).
The intuitive answer I feel is that they shouldn't be able to, as lewis acids and bases are defined only by their a... |
Consider the reaction $\ce{A <=> B}$. Let $k_f$, $E_A$, and $A$ denote the forwards rate constant, activation energy, and pre exponential factor, respectively. Let $k_r$, $E_A'$, and $A'$ denote the backwards rate constant, activation energy, and pre exponential factor, respectively. I seem to have determined the follo... |
New relationship between exponential factors and entropy of a reaction? |
If we look at the character table of $\ce{NH3}$ we see that these are the symmetry elements ${E, 2 C_3, 3 \sigma_v}$ present in the molecule. My question is - why are there $2 C_3$ rotation axes? Shouldn't there be only one which is present perpendicular to the plane consisting of 3 $\ce{H}$'s?
|$C_{3v}$|$E$|$2 C_3$... |
If we look at the character table for the $C_\mathrm{3v}$ point group (which $\ce{NH3}$ is an example of), we see that these are the symmetry elements ${E, 2 C_3, 3 \sigma_v}$ present in the molecule. My question is — why are there $2 C_3$ rotation axes? Shouldn't there be only one, which is perpendicular to the plane ... |
How are there two C3 rotation axes in ammonia? |
The question actually relates to Titanium piercings. Per Wikipedia on the topic of [Body Piercing Materials](https://en.wikipedia.org/wiki/Body_piercing_materials), to quote:
>Titanium body jewelry is often manufactured in either commercially pure grades 1 to 4, grade 5 TI6AL4V alloy or grade 23 Ti6AL4V ELI alloy.... |
**How strong is the "hydrophobic force"?**\
\
Hydrophobic interactions are weak interactions but can have greater strength than hydrogen bonds. I find the strength of the hydrogen bond in literature to be near 1 pN. Finding the strength of the "hydrophobic bond" has proven to be a bit more elusive. I would guess that... |
I can look up the enthalpy of formation of water vapor and get -241,826 KJ/mol. I want to use this to compute the total energy of water vapor at STP from the energies of O2 and H2 gas. What I don't know is whether I should use the electronic energies of H2 gas and O2 gas or the total energies of H2 gas and O2 gas, whic... |
Does the enthalpy of formation include translational and rotational energy? |
According to the book "The Chemistry of Organophosphorus Pesticides", the insecticide Chlormephos (S-(chloromethyl) O,O-diethyl phosphorodithioate) has an oral LD50 in rats of 7 mg/kg. For reference, the oral LD50 in rats for diisopropyl fluorophosphate is around 5 mg/kg. Why is chlormephos only slightly less toxic tha... |
Why is Chlormephos highly toxic despite requiring metabolic activation? |
If you have a bottle of water, a closed system, some of the water molecules in the liquid phase will have enough energy to escape that phase, forming water vapour, contributing to vapour pressure, based on the accepted answer for [this question][1].
[1]: https://chemistry.stackexchange.com/questions/7449/why-doe... |
Can you use vapour pressure to do work? |
How to plot an adiabatic potential in dihydrogen H2 molecule with ORCA calculation?
! RHF OPT def2-QZVPP
* xyz 0 1
H 0.000000 0.00000 0.00000
H 0.800000 0.00000 0.00000
*
[![enter image description here][1]][1]
[1]: https://i.stac... |
ORCA: How to plot an adiabatic potential in dihydrogen H2 molecule? |
I stared to study ORCA, and I try to obtain classical results for dihydrogen as for example. I need to get a starting point to understand what needs to be done.
So, How to plot an adiabatic potential in dihydrogen H2 molecule with ORCA calculation?
! RHF OPT def2-QZVPP
* xyz 0 1
H 0.0... |
I stared to study ORCA, and I try to obtain classical results for dihydrogen as for example. I need to get a starting point to understand what needs to be done.
So, How to plot an adiabatic potential in dihydrogen H2 molecule with ORCA calculation?
! RHF OPT def2-QZVPP
%geom Scan
B 0 1 = 1.0, 3.0, 12... |
I’m typing this from my phone...sorry if the quality is sub par.
I have a very involved spreadsheet from a colleague of mine that was put together in 1994. The spreadsheet calculates the excess air involved in combusting landfill gas in an enclosed flare. I’m trying to step my way through it little by little.
A... |
I am looking at investigating factors affecting the solubility of drugs using databases. So far, I am thinking of having my independent variables being the polar surface area, melting point, and size. My dependent variable would be lipophilicity. The reason why I am not directly measuring the solubility is that databas... |
Can I use lipophilicity (partition coefficient) as a way to quantify solublity? |
Given a bottle of water, a closed system, some of the water molecules in the liquid phase will have enough energy to escape that phase, forming water vapour, contributing to vapour pressure.
Now consider the simple setup below:
[![enter image description here][2]][2]
Water is used as an example, does not hav... |
Can vapour pressure be used to 'generate' work for free? |
1) Consider Gibb's free energy $G = H - TS$. Can $G$ ever be negative? (note, I am not talking about $\Delta G$)
2) What about $H$ and $S$? Are they also nonnegative?.
3) Is $H \ge S$ always?
|
Can G, H, and S be negative? |
1) Consider Gibb's free energy of a reaction in a closed system $G = H - TS$. Can $G$ ever be negative? (note, I am not talking about $\Delta G$)
I would suspect no because there is always some energy on every system.
2) What about $H$ and $S$? Are they nonnegative?
I would suspect yes because if there are bon... |
In literature the stretching mode of $\ce{CO}$ is often said to be the diagnostic criteria for strength of back-donation by virtue of weakening the $\ce{CO}$ bond. However, when speaking about homoleptic carbonyls, the vibrations of individual $CO$ ligands interact, forming symmetric and asymmetric modes with considera... |
In the chapter [Environmental Chemistry](https://ncert.nic.in/textbook.php?kech2=7-7) in our textbook it's given that Powder of Kernel of Tamarind seeds can be used for water treatment as a substitute for alum.
But if I understand correctly, alum ionizes in water and these ions neutralize the electrical double layer... |
Contaminated brake fluid conducts electricity. In the automotive repair world, brake fluid is considered contaminated by two ways:
1. Brake fluid is hygroscopic. Higher water content in brake fluid means lower boiling point. Brake pads/rotors get hot which can boil the water near near the pads/rotors. Boiled water is ... |
Why does contaminated brake fluid conduct electricity? Using a voltmeter to test for water contamination in brake fluid |
I’m typing this from my phone...sorry if the quality is sub par.
I have a very involved spreadsheet from a colleague of mine that was put together in 1994. The spreadsheet calculates the excess air involved in combusting landfill gas in an enclosed flare. I’m trying to step my way through it little by little.
A... |
I know the that it(Resonance) is the delocalisation of pi electrons but how and why are those electrons delocalised? What is the driving force that causes the effect? |
What Resonance is, exactly? |
What is Resonance, exactly? |
Why are the "extents of reaction" the same for all reactants and products? |
More specifically why doesn’t both oxygen and hydrogen appear everywhere? If the electricity just breaks apart bonds wouldn’t the hydrogen and oxygen just immediately turn into gas and bubble up wherever they split apart? Why does each atom wait to turn into gas until they reach a particular electrode? |
In hydrolysis, why does oxygen only appear on the anode? |
According to the assumptions of Constant P and T and no non mechanical work, we get
ΔG=ΔH-TΔS
But there is another form of the Gibbs free energy equation which takes Reversible process and no non mechanical work as assumption
dG=Vdp-SdT
If I Use the assumptions constant Pressure and Temperature, according ... |
In electrolysis, why does oxygen only appear on the anode? |
Even [*pure* water is *somewhat* ionized][1]. If water is more conductive than *pure* brake fluid, the test is valid. Why don't you try this as an experiment? To sample(s) of brake fluid fresh from a new, unopened, can, add distilled water, drop by drop, stirring each time and look for a change in conductivity. Measure... |
Is there a decent on-line source for dissociation constants for acids and bases as CRC alternative?
This chemistry stackexchange old answer no longer has valid links:
https://chemistry.stackexchange.com/questions/6919/is-there-an-online-database-of-acid-and-basic-dissociation-constants
I can only find abrupt a... |
I used to work in a microbiology lab and they used zinc acetate as O2 absorber for the anaerobic chamber. Was this an efficient way to scrub O2 from the air? I am asking because I was to make an N2 gas source by removing the oxygen from airflow. I only need to be able to produce at most 500 ccm of 99% N2. Is there some... |
How efficient is Zinc Acetate as an Oxygen absorber? |
I used to work in a microbiology lab and they used zinc acetate as O2 absorber for the anaerobic chamber. Was this an efficient way to scrub O2 from the air? I am asking because I want to make an N2 gas source by removing the oxygen from airflow. I only need to be able to produce at most 500 ccm of 99% N2. Is there som... |
At constant pressure, which is the usual condition for chemical reactions, heat absorbed/released by the system is the same thing as enthalpy change. According to the Gibbs equation,
$$\mathrm dG = \mathrm dH - T\,\mathrm dS = \mathrm dH - đq$$But, $\mathrm dH=\mathrm đq$ at constant a pressure. So is the Gibbs ener... |
Is the change of the Gibbs free energy always zero at constant pressure? |
I had this question:
> Naturally occurring europium consists of two isotopes with a mass of 151 and 153. Europium-151 has an abundance of 48.030 and, and europium-153 has a natural abundance of 51.970. What is the atomic mass of europium? **Do not include units. Be sure to round to the correct number of significant... |
> In electrolysis, why does oxygen only appear on the anode?
Easy way to *remember* this is that oxidation occurs at the anode (both start with vowels), and oxidation implies a loss of hydrogen. If we lose hydrogen from water, we are left with oxygen.
If you wish to understand it crudely, the concept is that an... |
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