instruction stringlengths 15 21.8k |
|---|
> Yet, being at standard state does not mean that the reaction is at equilibrium, in fact Q=1 could be greater or less than K.
$\Delta_{\text{R}} G^\circ $ and K are linked. If $\Delta_{\text{R}} G^\circ $ is positive, K will be less than one. Consequently, Q > K and the reaction will go backwards.
> But yet $\De... |
If a gas expand in vaccum(Pex.) =0.Then why the work done is 0?Since the gas is expanding, it is doing some work on the piston so the work done must have some negative value. |
Why work done Is 0 and why not a negative value? |
If a gas expand in vacuum, $P_{ex.} =0$. Then why is the work done 0? Since the gas is expanding, it is doing some work on the piston so the work done must have some negative value. |
Selective reduction of nitro group to amine, in benzene ring containing nitrile? |
Let's suppose we want to titrate a solution containing an unknown monoprotic and weak acid. We use a strong base, such as $NaOH$. When the number (and moles) of hydroxide ions is equal to the amount of hydronium ions, here we have the equivalence point.
When titrating a strong monoprotic acid the equivalence points... |
I understand that the first step is the calculate the rotational constant. So to do this I assume I would use one frequency value and one J value? And the equation to use would be
wavenumber = BJ(J+1) right?
If I do this with the numbers for J=3 then I get 1.28 for B, which is apparently incorrect. I have seen ... |
[![enter image description here][1]][1]
I can't rationalize why S- is a worse nucleophile than N-. I thought nucelophilicity was related to electronegativity, the more electronegative an atom is, the less of a nucleophile it is. Sulfur is less electronegative than Nitrogen. What concept am I not considering or misun... |
Why is N- a better nucleophile than S-? |
Let's suppose we want to titrate a solution containing an unknown monoprotic and weak acid. We use a strong base, such as $\ce{NaOH}$. When the number (and moles) of hydroxide ions is equal to the amount of hydronium ions, here we have the equivalence point.
When titrating a strong monoprotic acid the equivalence p... |
> Let's suppose we want to titrate a solution containing an unknown monoprotic and weak acid. We use a strong base, such as $\ce{NaOH}$. When the number (and moles) of hydroxide ions is equal to the amount of hydronium ions, here we have the equivalence point.
The equivalence point is, when the molar amount of the sp... |
> Let's suppose we want to titrate a solution containing an unknown monoprotic and weak acid. We use a strong base, such as $\ce{NaOH}$. When the number (and moles) of hydroxide ions is equal to the amount of hydronium ions, here we have the equivalence point.
The equivalence point is, when the molar amount of the sp... |
If Resonance can stabilize both carbo cation and anion then why can't hyperconjugation stabilize carbanion ? Since both Resonance and Hyperconjugation are pretty much the same, i.e both involve delocalisation or diffusion of electrons( at least in model) ? |
Why hyperconjugation can't stabilize carbanion? |
I am attempting to perform a Fisher esterification of 3-butenoic acid (vinyl acetic acid). I believe that this should theoretically work and not disturb the unsaturated region of the molecule, but I'm not certain. Has anyone had any practical experience with this in the lab or seen any literature referencing a Fischer ... |
>Estimate the bond length of 12C16O (pure rotational spectrum) given J''=3 (15.356 cm-1) and J'=9 (38.356)
I understand that the first step is the calculate the rotational constant. So to do this I assume I would use one frequency value and one J value? And the equation to use would be
$$\nu = BJ(J+1)$$
If I... |
So a conjugated system is a system of connected p orbitals or alternating single and multiple bonds.
I know that conventionally, we count the number of adjacent parallel p orbitals or alternating single-double bonds to see which molecule is "more conjugated" or not. However, when considering the following molecules... |
How can we calculate the "degree" of conjugation? |
It is common practice to define the standard state of a gas when describing its thermodynamic properties. For instance, the free energy of an ideal gas can be defined relative to the free energy in its standard state (the gas at a partial pressure of 1 bar and at the same temperature), as
$$G = G^\circ + RT\log\lef... |
The starch and iodide test is to detect amylose, a polysaccharide. We add an iodide solution to a sample and observe a color change with the starch; it turns dark blue. I am doing a bio/chem experiment on how pH changes Amylase digestion of Starch.
My recent trials have all failed, as the amylase starch solution ... |
It's well known that activated charcoal is an adsorbent and due to very big surface area per unit of mass it can adsorb a lot of particles.
Let's take as an example for my question [this product](https://www.amazon.com/dp/B01N7NHVZK/) on Amazon.
My questions are the followings:
1. How much do this apply to th... |
Is activated charcoal an air purifier? |
**Question:** What might serve as an initial starting photocatalyst for this large water-splitting solar simulator? Surely there must have been some planned experiments!
----
The Gizmodo article [Insane Light System Blasts the Energy of 10,000 Suns][1] and Phys.org's [Let there be light: German scientists test 'a... |
I think that the molecule can be drawn in three ways but the book says that the correct answer is option D i.e.,2 can anyone explain how ?[![][1]][1]
[1]: https://i.stack.imgur.com/f4L0l.jpg |
How many resonance structures can be drawn for the following molecule? |
> Let's suppose we want to titrate a solution containing an unknown monoprotic and weak acid. We use a strong base, such as $\ce{NaOH}$. When the number (and moles) of hydroxide ions is equal to the amount of hydronium ions, here we have the equivalence point.
The equivalence point is, when the molar amount of the sp... |
For Question 2; I think that the molecule can be drawn in three ways but the book says that the correct answer is option D i.e.,2 can anyone explain how ?
[![General Organic Chemistry question][1]][1]
[1]: https://i.stack.imgur.com/f4L0l.jpg |
> Let's suppose we want to titrate a solution containing an unknown monoprotic and weak acid. We use a strong base, such as $\ce{NaOH}$. When the number (and moles) of hydroxide ions is equal to the amount of hydronium ions, here we have the equivalence point.
The equivalence point is, when the molar amount of the sp... |
The situation is as follows:
> A sample of $\pu{19.40 g}$ from a certain compound consisting only in $\ce{K, Cr}$ and $\ce{O}$, receives a treatment. This gives $\pu{7.6 g}$ of $\ce{Cr2O3}$ and $\pu{9.70 g}$ of the compound is transformed into $\pu{13.85 g}$ of $\ce{KClO4}$. Using this information find the empirical... |
Do the procedure used to find the empirical formula from combustion analysis be extended in other cases when is not specifically mentioned? |
> Let's suppose we want to titrate a solution containing an unknown monoprotic and weak acid. We use a strong base, such as $\ce{NaOH}$. When the number (and moles) of hydroxide ions is equal to the amount of hydronium ions, here we have the equivalence point.
The equivalence point is, when the molar amount of the sp... |
I have a doubt, Ideal solutions are solutions where intermolecular forces between solute-solute and solvent-solvent are nearly equal to solute-solvent. Since intermolecular forces between A-A = B-B, doesn't that mean, they both have same volatility? But in Raoult's law, the graph shows that one of the vapour pressure i... |
If volatility depends on intermolecular forces, then why in Raoult's law, two substances have different volatility? |
So I am performing a relatively simple coprecipitation experiment to synthesize ceramics. All my precursors are in aqueous solutions. But due to the high surface tension of water, drying the water is affecting my surface area and porosity. So I have introduced a solvent washing step, where I try to replace water by et... |
I've been given the following exercise in organic chemistry, and I'm at a complete loss. The text book doesn't cover the subject at all. I have some knowledge of melonic ester synthesis. As an undergraduate student in biology, I have a really hard time grasping the concepts, so an in-depth explanation would be much app... |
Why in the particle in a box model do the values of n begin at 1 but in the harmonic oscillator they begin at 0? I understand what the wave-functions and their corresponding probabilities look like and that the PIB has 0 nodes for n=1 which means the number of nodes is n-1, so for n = 0 it would have -1 nodes which is ... |
At the instant the boiling point is reached, the vapour pressure of the solution should be equal to atm. pressure. And since the boiling is continued the pressure will keep on increasing. Thus the relationship between the pressures will be be $P_5 ... |
The relationship between the temperatures at different times and pressures at different times is? |
I want to use some fine WRe wire (50 micron diameter, 80/20) in a particular environment where it has to conduct a few millamps of current while supporting 100g of mass. The problem being the contact between the wire and its copper/bronze supports has to be extremely consistent. We are looking for changes in current in... |
Tungsten-Rhenium alloy connections to Copper. Methods? |
Let's suppose we want to titrate a solution containing an unknown monoprotic and weak acid. We use a strong base, such as $\ce{NaOH}$. When the number (and moles) of hydroxide ions coming directly from the base is equal to the amount of hydronium ions due to the acid, here we have the equivalence point.
When titrat... |
I think that three distinct products may result namely
a)1,1-Dichloro-2-methylpropane. b) 1,2-Dichloro-2-methylpropane
c)1,3-Dichloro-2-methylpropane .
But the book says only two distinct products may form .Can anyone explain how ? |
How many distinct dichlorination products can result when isobutane is subjected to free radical chlorination? |
My colleagues are looking to replace their old floorstanding WD-XRF with a newer, smaller benchtop instrument. Everywhere we've looked the newer XRFs are energy-dispersive (ED), which I understand are often preferred over WD for being lower maintenance, among other reasons.
I'm trying to find a clear answer on how ... |
Does ED-XRF heat the sample? |
I am doing an electrolysis experiment with two copper wires inside of test tubes that are both submerged underwater, with 20v per wire. Test tube A is creating oxygen gas at a high rate, but test tube B is creating a smoke-like gas that is heavier than the water and coming out of the test tube that is submerged in wate... |
copper wire smoking underwater? |
I'm coming from a Physics background and am trying to make sense of the energy level diagram for para-helium and ortho-helium.
From what I've gathered each column shows the different energy levels for different orbitals so that for example the leftmost column with $^1S$ written on top shows the energy levels of 1s,... |
We did an experiment where copper iodide 4-methylpyridine and copper iodide imidazole was formed and now we are asked what orbital the electron is excited from and to.
After much research we still struggle to answer this question. We came to the conclusion that the structure of our two products are tetrahedral and t... |
According to Hard-Soft Acid Base (HSAB) Theory, "soft" lewis bases bind to "soft" lewis acids, and "hard" lewis bases bind to "hard" lewis acids.
$\ce{Fe3+}$ is a hard lewis acid. In $\ce{SCN-}$, either the $\ce{N}$ or the $\ce{S}$ side of the molecule can bind with $\ce{Fe3+}$. Of the two, $\ce{N}$ is the harder le... |
Why does thiocyanate bind to Fe3+ with the S side instead of the N side? |
We did an experiment where copper iodide 4-methylpyridine and copper iodide imidazole was formed and now we are asked what orbital the electron is excited from and to.
After much research we still struggle to answer this question. We came to the conclusion that the structure of our two products are tetrahedral and t... |
According to hard and soft acids and bases (HSAB) theory, "soft" Lewis bases bind to "soft" Lewis acids, and "hard" Lewis bases bind to "hard" Lewis acids.
$\ce{Fe^3+}$ is a hard Lewis acid. In $\ce{SCN-}$, either the $\ce{N}$ or the $\ce{S}$ side of the molecule can bind with $\ce{Fe^3+}$. Of the two, $\ce{N}$ is t... |
Why does thiocyanate bind to Fe³⁺ with the S side instead of the N side? |
I am doing an electrolysis experiment with two copper wires inside of test tubes that are both submerged underwater, with 20 V per wire. Test tube **A** is creating oxygen gas at a high rate, but test tube **B** is creating a smoke-like gas that is heavier than the water and coming out of the test tube that is submerge... |
I have a valuable soccer ball. It is not real leather, but a synthetic leather.
I used this cleaning agent to remove a few marks:
https://www.amazon.co.uk/Motsenbockers-Lift-Off-Graffiti-Remover-Trigger/dp/B00N3B25LU
However, I stupidly forgot to wait for the ball to dry and then placed it within an orange pla... |
The title of the question is about sample heating by ED-XRF instrument. Yet, OP is wondering its limitations and like to understand what kind of compounds analysts might lose to some sample heating if they switch to ED-XRFs (bench-top?). I hope this may be addressed by MaxW, when OP has said whay kind of samples they a... |
The title of the question is about sample heating by ED-XRF instrument. Yet, OP is wondering its limitations and like to understand what kind of compounds analysts might lose to some sample heating if they switch to ED-XRFs (bench-top?). I hope this may be addressed by MaxW, when OP has said whay kind of samples they a... |
I have a doubt, Ideal solutions are solutions where intermolecular forces between solute-solute and solvent-solvent are nearly equal to solute-solvent. Since intermolecular forces between A-A = B-B, doesn't that mean, they both have same volatility? But in Raoult's law, the graph shows that one of the vapour pressure i... |
Why does the rotational constant B decrease and transition spacings decrease as the mass of a particle increase?
I understand from a purely equation perspective that since
B = h/8pi^2cI
that as I increases the denominator increases and so B decreases. But what is the physical reasoning behind this? Why or in... |
A reading of the [Corey-Schmidt<sup>1</sup>][1] paper on the oxidation of non-conjugated primary alcohols and aldehydes to the corresponding carboxylic acids with dipyridinium dichromate (PDC) in dimethylformamide (DMF) makes no explicit mention of drying DMF but flame-dried glassware is employed. Perhaps this implies ... |
A reading of the [Corey-Schmidt<sup>1</sup>][1] paper on the oxidation of non-conjugated primary alcohols and aldehydes to the corresponding carboxylic acids with dipyridinium dichromate (PDC) in dimethylformamide (DMF) makes no explicit mention of drying DMF but flame-dried glassware is employed. Perhaps this implies ... |
> Let's suppose we want to titrate a solution containing an unknown monoprotic and weak acid. We use a strong base, such as $\ce{NaOH}$. When the number (and moles) of hydroxide ions is equal to the amount of hydronium ions, here we have the equivalence point.
The equivalence point is, when the molar amount of the ... |
Why does the rusting process start from the bent/squeezed portion of iron? |
[![enter image description here][1]][1]
I circled what I believe to be the chiral centers and I added the locants for the longest carbon chain. One of the chiral centers is in a side chain, so that carbon doesn't have a locant. How should its absolute configuration be included into the IUPAC name?
[1]: https://i.... |
How is the chirality of sidechains written in the IUPAC name? |
Its given in my book that alkyl halides react with alcoholic potassium cyanide to give alkyl cyanide through $\mathrm{S_N2}$ mechanism.
But why do we need to use alcoholic $\ce{KCN}$ (potassium cyanide dissolved in alcohol)? My understanding is that polar protic solvent favours $\mathrm{S_N1}$ over $\mathrm{S_N2}.$ |
> Let's suppose we want to titrate a solution containing an unknown monoprotic and weak acid. We use a strong base, such as $\ce{NaOH}$. When the number (and moles) of hydroxide ions is equal to the amount of hydronium ions, here we have the equivalence point.
The equivalence point is, when the molar amount of the ... |
> Let's suppose we want to titrate a solution containing an unknown monoprotic and weak acid. We use a strong base, such as $\ce{NaOH}$. When the number (and moles) of hydroxide ions is equal to the amount of hydronium ions, here we have the equivalence point.
The equivalence point is, when the molar amount of the ... |
> Let's suppose we want to titrate a solution containing an unknown monoprotic and weak acid. We use a strong base, such as $\ce{NaOH}$. When the number (and moles) of hydroxide ions is equal to the amount of hydronium ions, here we have the equivalence point.
The equivalence point is, when the molar amount of the ... |
I was doing some homework and I was reading about how ICP is suitable for mass spectrometry and it said how its high temperature favours ionization which is good in MS. But also, because the temperature is so high in a plasma, wouldn't there be a very high collisional frequency which could cause side reactions/disrupti... |
Why does the rotational constant B decrease and transition spacings decrease as the mass of a particle increase?
I understand from a purely equation perspective that since
$$B = \frac{h} {8\pi ^2 cI}$$
that as $I$ increases the denominator increases and so $B$ decreases. But what is the physical reasoning be... |
I understand that increasing the concentration of reactants in a galvanic cell generally causes the voltage of the cell to increase. But is that really the case always? Consider a standard cell of zinc and copper, 1M and 1L each solution of copper nitrate and zinc nitrate in each half cell. What if I then, I. Another c... |
What is the oxidation state of copper in Gilman's reagent?In R-Cu bond the oxidation state is +1
.Thus in R-Cu-R bond the oxidation state has to be +2.But if that so why positive Li act as counter ion in Gilman's reagent?.And why is it named as dialkyl cuprate (ate- for anionic complexes)? |
What is the oxidation state of copper in Gilman's Reagent? |
Editing for clarity and more details.
My colleague has been using XRF to quantitatively analyze 47-mm diameter Teflon membrane filters for metals, minerals, and rare earths. Much of their analysis has been focused on quantifying metals like iron, steel, and copper. It seems they are looking into replacing their larg... |
XRF is touted as "non-destructive," but what actually happens to the sample? |
XRF is "non-destructive," but what actually happens to the sample? |
Outline the steps involved in the Hartree–Fock method for the calculation of molecular electronic structure.
I understand the basics of HF, in that it does not account for electron correlation (neither non-dynamical or dynamical) but I do not understand what the question means by steps.
Are the steps of the HF m... |
I think this question is same as wondering as to why a certain cancer patient has a cancer in the kidney but not on the skin? Nobody knows. In the same way, rusting is a random process as well. It can start anywhere. This iron sheet is not ultrapure iron sheet of homogeneous nature. One can see a lot of spots in trough... |
Outline the steps involved in the Hartree–Fock method for the calculation of molecular electronic structure.
I understand the basics of HF, in that it does not account for electron correlation (neither non-dynamical or dynamical) but I do not understand what the question means by steps.
Are the steps of the HF ... |
I understand that increasing the concentration of reactants in a galvanic cell generally causes the voltage of the cell to increase. But is that really the case always?
Consider a standard cell of zinc and copper, 1 M and 1 L each solution of copper nitrate and zinc nitrate in each half cell. Another cell, increased... |
[![enter image description here][1]][1]
I circled what I believe to be the chiral centers and I added the locants for the longest carbon chain. One of the chiral centers is in a side chain, so that carbon doesn't have a locant. How should its absolute configuration be included into the IUPAC name?
[1]: https:... |
How is the chirality of side chains written in the IUPAC name? |
[![enter image description here][1]][1]
I circled what I believe to be the chiral centers and I added the locants for the longest carbon chain. One of the chiral centers is in a side chain, so that carbon doesn't have a locant. How should its absolute configuration be included into the IUPAC name?
[1]: https://i.... |
How is the chirality of sidechains written in the IUPAC name? |
> Outline the steps involved in the Hartree–Fock method for the calculation of molecular electronic structure.
I understand the basics of HF, in that it does not account for electron correlation (neither non-dynamical or dynamical) but I do not understand what the question means by steps.
Are the steps of the H... |
What are the steps of Hartree-Fock Theory? |
A reading of the [Corey-Schmidt<sup>1</sup>][1] paper on the oxidation of non-conjugated primary alcohols and aldehydes to the corresponding carboxylic acids with dipyridinium dichromate (PDC) in dimethylformamide (DMF) makes no explicit mention of drying DMF but flame-dried glassware is employed. Perhaps this implies ... |
What is the oxidation state of copper in Gilman's reagent? In $\ce{R-Cu}$ bond the oxidation state is +1. Thus in $\ce{R-Cu-R}$ bond the oxidation state has to be +2. But if that so why positive $\ce{Li}$ act as counter ion in Gilman's reagent? And why is it named as dialkyl cuprate (-ate for anionic complexes)? |
You know that for a generic system which during a process exchanges heat with a reservoir at a constant temperature $T_{a}$ it holds:
$$\Delta G=\Delta H-T_{a}\Delta S$$
Where:<br>
$\star)$$\Delta G$ is the Gibbs free energy change of the system during the process.<br>
$\star)$$\Delta H$ is the enthalpy change of t... |
Below is a chemistry practice problem. I am curious why the change in heat of the oxygen molecules affect the reaction?
Methylhydrazine (CH6N2) is commonly used as a liquid rocket fuel. The combustion reaction is below.When 4.00 g of methylhydrazine is combusted in a calorimeter, the temperature increases from 25.0... |
Below is a chemistry practice problem. I am curious why the change in heat of the oxygen molecules doesn't affect the calculations.
Methylhydrazine (CH6N2) is commonly used as a liquid rocket fuel. The combustion reaction is below.When 4.00 g of methylhydrazine is combusted in a calorimeter, the temperature increas... |
So we looked at the Stern-Gerlach experiment and I understand the basic principle; when a stream of silver atoms is passed through an inhomogeneous magnetic field, and the Ag atoms are deflected either up or down depending on their spin.
What I don't understand is how this proves that spin operators don't commute. ... |
What is the physical significance of the fact that spin operators do not commute? |
Tight binding model for systems with finite dimensions? |
Tight binding model for nanoparticles as finite systems? |
I'm trying to dry air by leading it through calcium chloride.
I'm measuring the resulting humidity with a simple capacitive humidity sensor. I do not see measurements below 10% relative humidity, but it is quite possible that it is a result of a calibration error (The sensor is not actually calibrated.)
But how d... |
Can I completely dry air with calcium chloride? |
Calcium chloride is deliquescent, it is hygroscopic, so much so that it dissolves in the water it has attracted by hygroscopy.
Sulfuric acid is hygroscopic, even if not anhydrous. So a solution containing water can be hygroscopic.
Is a concentrated solution of calcium chloride that was created by the solid salt a... |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.