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*p*-chlorophenol is more acidic than *p*-fluorophenol due to presence of vacant d orbitals. But then is *p*-bromophenol more acidic than *p*-chlorophenol since it has vacant f orbitals also? But I guess that’s wrong, isn’t it? Please give your suggestions. |
Is p-bromophenol more acidic than p-chlorophenol? |
![/Users/nehaparmar/Downloads/IMG_1655-1.JPG][1]
In the textbook passage that is seen in the picture, I am having trouble understanding the third last sentence in the paragraph that starts with "2." The statement reads: "It cannot; any solution containing both NH4+ and OH- must also contain NH3. The OH- and NH4+ r... |
This question is simpler than the previous one about intuition of entropy; I just need to know whether the T term in dSSurr = -dH/T refers to the temperature of the surroundings or the system. I think it needs to be both, no? For example, for water to boil, the system must have T $\geq$ 100 degrees C. But can it also b... |
In entropy change of surroundings, what is T? |
This question is simpler than the previous one about intuition of entropy; I just need to know whether the T term in dSSurr = -dH/T refers to the temperature of the surroundings or the system. I think it needs to be both, no? For example, for water to boil, the system must have T $\geq$ 100 degrees C. But can it be sai... |
The problem asks to determine the [H+] in a 0.20 M solution of Na3PO4. The Ka of HPO4- was given (4.5*10^-13), which then allows one to calculate the corresponding Kb(2.22*10^-2).
As any acid-base problem, I simply set up the expression $x^2/.20M=2.22*10^-2$ with x being [OH-] and solved for [H+].
However, the s... |
This question is simpler than the previous one about intuition of entropy; I just need to know whether the $T$ term in $dS_{Surr} = \frac{-dH}{T}$ refers to the temperature of the surroundings or the system. I think it needs to be both, no? For example, for water to boil, the system must have $T \geq$ 100 degrees C. Bu... |
I be mistaken, but are you referring to vapor pressure?
Vapor pressure or equilibrium vapour pressure is defined as the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature in a closed system. The equilibrium vapor pressure is an indication of a... |
Calculate the number of moles of NO₂ (g) produced per hour per liter of air? |
![/Users/nehaparmar/Downloads/IMG_1655-1.JPG][1]
In the textbook passage that is seen in the picture, I am having trouble understanding the third last sentence in the paragraph that starts with "2." The statement reads: "It cannot; any solution containing both $\ce{NH4+}$ and $\ce{OH-}$ must also contain $\ce{NH3}... |
A reaction of importance in the formation of smog is that between ozone and nitrogen monoxide described by
$\ce{O3(g) + NO(g)->O2(g) + NO2(g)}$
the rate law for this reaction is:
rate of reaction = $\ce{k[O3][NO]}$
Given that k = 2.98 × 106 M<sup>–1</sup>·s<sup>–1</sup> at a certain temperature, calculate t... |
A reaction of importance in the formation of smog is that between ozone and nitrogen monoxide described by
$\ce{O3(g) + NO(g)->O2(g) + NO2(g)}$
the rate law for this reaction is:
rate of reaction = $\ce{k[O3][NO]}$
Given that k = $2.98 × 10^6$ M<sup>–1</sup>·s<sup>–1</sup> at a certain temperature, calculat... |
Is 1.5M NaOH a strong enough base to deprotonate benzyl alcohol? I realize that NaOH generally does not deprotonate benzyl alcohol, but we performed an extraction in a Fischer esterification lab with benzyl alcohol an acetic acid to synthesize benzyl acetate. Acetic acid was added in excess, and the final ester product... |
Is 1.5M NaOH a strong enough base to deprotonate benzyl alcohol? |
The problem asks to determine the $\ce{[H+]}$ in a 0.20 M solution of $\ce{Na3PO4}$. The K<sub>a</sub> of $\ce{HPO4-}$ was given (4.5 x 10<sup>-13</sup>), which then allows one to calculate the corresponding K<sub>b</sub>(2.22 x 10<sup>-2</sup>).
As any acid-base problem, I simply set up the expression $\frac{x^2}{0... |
I'd like to accurately calibrate a digital thermometer I'm building in the range $50^\circ$ to $120^\circ$ Celsius.
I'm aware that one can buy various chemicals that have melting points in this range, but are there any readily available household / pharmaceutical items I could use instead? |
What is the pH of a solution prepared by mixing 25.00 mL of 0.10 M methylamine, CH3NH2,
with 25.00 mL of 0.10 M methylammonium chloride, CH3NH3Cl? Assume that the volume of
the solutions are additive and that Kb = 3.70 × 10-4 for methylamine.
1) First, I multiplied .025 L with .10 M and received .0025 moles.I then... |
Why are inert gas (especially Xenon) compounds powerful oxidizing agents? |
Would it be feasible to jury-rig an automotive catalytic converter to make Nitric Oxide for use in the Ostwald Process? Given reasonable safety precautions, would it be safe enough to be practical for a home lab? |
jury-rigging an automotive catalytic converter for use in the Ostwald Process? |
I have two questions regarding chemical shifts on aromatic systems.
First, what does being near an aromatic system do to protons? If we look at the spectra of 1-napthalenemethanol and then 9-anthracenemethanol, the peak of the two aliphatic protons of the benzylic methylene group get shifted way up. Can someone exp... |
Proton NMR questions. What happens to chemical shifts of protons close to aromatic systems? |
I have two questions regarding chemical shifts on aromatic systems.
First, what does being near an aromatic system do to protons? If we look at the spectra of 1-napthalenemethanol and then 9-anthracenemethanol, the peak of the two aliphatic protons of the benzylic methylene group get shifted way up. Can someone exp... |
What happens to chemical shifts of protons close to aromatic systems in ¹H-NMR? |
The aromaticity found in certain ring systems (e.g. benzene, see [Hückel's rule][1]) causes a magnetic field because of the circular motion of the electrons in the ring (see picture).
![Clayden et al. Organic Chemistry 2nd edition, p. 277][2]
(Source: Clayden et al. Organic Chemistry 2nd edition, p. 277)
Thi... |
In determining the empirical formula of a compound which constitutes a diatomic molecule, should we calculate the molar mass of the divalent molecule by multiplying the molar mass of the element by 2, or should we leave it as it is. Because, I happened to come across a problem, where I had to calculate the empirical fo... |
In determining the empirical formula of a compound which constitutes a diatomic molecule, should we calculate the molar mass of the divalent molecule by multiplying the molar mass of the element by 2, or should we leave it as it is. Because, I happened to come across a problem, where I had to calculate the empirical fo... |
Do I have to consider the molecular mass of the oxygen atom or the diatomic oxygen molecule when determining the empirical formula of an iron oxide? |
In determining the empirical formula of a compound which constitutes a diatomic molecule, should we calculate the molar mass of the divalent molecule by multiplying the molar mass of the element by 2, or should we leave it as it is. Because, I happened to come across a problem, where I had to calculate the empirical fo... |
What is the pH of a solution prepared by mixing 25.00 mL of 0.10 M methylamine, CH3NH2,
with 25.00 mL of 0.10 M methylammonium chloride, CH3NH3Cl? Assume that the volume of
the solutions are additive and that Kb = 3.70 × 10-4 for methylamine.
1) First, I multiplied .025 L with .10 M and received .0025 moles.I then... |
I am having some trouble with understanding the NOE. The carbon NMR spectra can't be integrated, because the protons attached to the carbon atoms will make primary carbon atom relaxation faster than tertiary, **so their peaks will have bigger intensity**. With a bigger acquisition time, the peaks will be more proportio... |
How do I get an accurate surface area from a nitrogen isotherm?
I've been doing some surface areas on MOFs and upon showing my boss the isotherms he asked me to convert them to show the "range", which will give the most accurate surface area.
I'm using Micromeritics ASAP-2020 software and I believe that you meas... |
How to calculator "accurate" surface area of a microporous material using Micromeritics equipment? |
What is the equation that demonstrates the relationship between molar conductivity and temperature? |
it is violet in trichloromethane , but brown in water. why? in Shriver Atkins book they tried to explain this by Molecular Orbital Theory which was not clear to me |
why iodine has different colors in different medium? |
How to calculate "accurate" surface area of a microporous material using Micromeritics equipment? |
It is violet in trichloromethane, but brown in water. why? In the Shriver Atkins book, they tried to explain this using *Molecular Orbital Theory* which was not clear to me |
Why is iodine different colors in different mediums? |
Why does iodine have different colors in different mediums? |
I understand this is a simple question (I’m in high school), but for some reason the numbers just are not working for me.
Given:
$$\Delta H^\circ_\text{c} = -1301\ \mathrm{kJ}\ \text{for}\ \ce{C2H2(g)}$$
$$\Delta H^\circ_\text{f} = -394\ \mathrm{kJ}\ \text{for}\ \ce{CO2(g)}$$
$$\Delta H^\circ_\text{f} = -242\ \m... |
A solution is created by mixing 250 mL of 1 M $\ce{HCl}$, 250 mL of 1 M $\ce{CH3COOH}$ and 500 mL of 1.5 M $\ce{CsOH}$.
The $K_\text{a}(\ce{CH3COOH}) = 1.8 \times 10^{-5}$
What is the pH of this solution?
I am stuck between $\ce{HCl}$ and $\ce{CsOH}$ since they are both a strong acid and base (respectively) me... |
Are the following processes exothermic or endothermic?
a) When solid $KBr$ is dissolved in water, the solution gets colder.
b) Natural gas ($CH_4$) is burned in a surface.
c) When concentrated $H_2SO_4$ is added to water, the solution gets very hot.
d) Water is boiled in a teakettle.
**Attempt at solutio... |
Exo- or endothermic? Clarification required regarding a few cases |
Many metals form compounds with s-block elements that are essentially entirely ionic. However, elements like silver, copper, lithium and so on, can form bonds that are significantly covalent in character. What are the factors that govern whether a particular metal will bond with significant covalent character? Is this ... |
What makes a metal more inclined to bond covalently? |
The second step of Djerassi's synthesis of 19-nor-17α-ethynyltestosterone (norethindrone), involves the protection of the ketone in position 3 via enolether formation, as in the picture:
![synthesis step][1]
What is the mechanism of this reaction? I couldn't find it anywhere. I suppose it should be similar to an ... |
Would it be feasible to jury-rig an automotive catalytic converter to make Nitric Oxide for use in the Ostwald Process for the production of Nitric Acid? Given reasonable safety precautions, would it be safe enough to be practical for a home lab? |
Solvent leveling means that strong acids completely dissociate in that solvent so it is impossible to distinguish between two acids that completely dissociate in it. A solvent levels and acid if the $K_a$ of that acid is greater than 1. However, that's not completely dissociated. An acid can have a $K_a$ of 2, 3 or 25 ... |
Why does solvent leveling occur? |
I think you are confusing terms:
*exothermic* means that it releases heat, that is energy, because the energy of the products is lower than the one of the reagents.
*endothermic* means that it absorbs heat (energy) because the products are at a higher level of energy than the reagents.
When a solution becomes... |
I'd like to accurately calibrate a digital thermometer I'm building in the range $50^\circ$ to $120^\circ$ Celsius.
I'm aware that one can buy various chemicals that have melting points in this range, but are there any readily available household / pharmaceutical items I could use instead?
From what I have read... |
Solvent leveling means that strong acids completely dissociate in that solvent so it is impossible to distinguish between two acids that completely dissociate in it. A solvent levels and acid if the $K_a$ of that acid is greater than 1. However, that's not completely dissociated. An acid can have a $K_a$ of 2, 3 or 25 ... |
When recharging a lead-acid battery, how are the terminals of the battery connected to the voltage source. I mean, do we connect the positive terminal of the battery to the negative terminal of the source and vice versa? Or does the positive go with the positive and the negative with the negative? |
How is a car battery recharged? |
I'm having a doubt on the mechanism of oxymercuration Demercuration reaction. How does the reaction, initially heading towards anti addition(after cyclic transition state formation) , get spoiled by NaBH4 and ends up being stereorandom? Can anyone point out the importance of using mercury as well? The explanation would... |
Solvent leveling means that strong acids completely dissociate in that solvent so it is impossible to distinguish between two acids that completely dissociate in it. A solvent levels and acid if the $K_\text{a}$ of that acid is greater than 1. However, that’s not completely dissociated. An acid can have a $K_\text{a}$ ... |
When recharging a lead-acid battery, how are the terminals of the battery connected to the voltage source. I mean, do we connect the positive terminal of the battery to the negative terminal of the source and vice versa? Or does the positive go with the positive and the negative with the negative? Also, are the electro... |
Would it be feasible to jury-rig an automotive catalytic converter for use in the Ostwald Process for the production of Nitric Acid? Given reasonable safety precautions, would it be safe enough to be practical for a home lab?
A Catalytic converter is a device used in cars to reduce Nitric oxide into nitrogen and Ox... |
Let's take a simple Daniell cell for example: ![Daniell cell][1]
[1]: https://i.stack.imgur.com/DRPk1.jpg
Where does the energy required to drive electrons through the external circuit and power up devices (like a light bulb) come from? Does the oxidation of zinc release that energy? And, does the reduction o... |
What's the source of electrical energy in galvanic cells? |
I'm having a doubt on the mechanism of oxymercuration Demercuration reaction.
How does the reaction, initially heading towards anti addition(after cyclic transition state formation) ,get spoiled by $\ce{NaBH4}$ and ends up being stereorandom? Can anyone point out the importance of using mercury as well? The explanati... |
The stereorandomization occurs in the formation of the cyclic mercurinium ion intermediate.
![formations of chiral mercurinium ion][1]
When the mercury acetate approaches the alkene, it can do so from either the top face:
![mercury approach from the top face][2]
or the bottom face:
![mercury approach fr... |
> Cobalt exhibits a more specific interaction with histidine tags,
> resulting in less nonspecific interaction than nickle. For this reason, cobalt >is the preferred divalent cation for purifying His-tagged proteins when
> high purity is a primary concern.
I read this last week, and I'm wondering, why is cobalt li... |
My problem sheet asks me: "Draw a mechanism for the formation of $\ce{EtCH2COOH}$ from the reaction of $\ce{MeCOCH(Et)COOEt}$ with $\ce{NaOH}$ in $\ce{EtOH}$"
This has got me stumped. The mechanisms that I have attempted use the hydroxide ion as the base/nucleophile, is this right? My initial thoughts were to make t... |
I've just found read that entropy increases through these reasons:
1. Changing the phase of the elements to a gas.
2. Increasing the molar mass increases the entropy.
I understand the first one, but I cant grasp the second one.
Because naturally you would think that $\ce{H2}$ would have a higher entropy than $\ce... |
Why is it that increasing the molar mass generally increases the Entropy? |
> Cobalt exhibits a more specific interaction with histidine tags, resulting in less nonspecific interaction than nickel. For this reason, cobalt is the preferred divalent cation for purifying His-tagged proteins when high purity is a primary concern.
I read this last week, and I'm wondering, why is cobalt like that... |
I've just found read that entropy increases through these reasons:
1. Changing the phase of the elements to a gas.
2. Increasing the **molar mass of that specific element** increases the entropy.
I understand the first one, but I cant grasp the second one.
Because naturally you would think that $\ce{H2}$ wo... |
What is the pH of a solution prepared by mixing 25.00 mL of 0.10 M methylamine, $\ce{CH3NH2}$,
with 25.00 mL of 0.10 M methylammonium chloride, $\ce{CH3NH3Cl}$? Assume that the volume of
the solutions are additive and that K<sub>b</sub> = 3.70 × 10<sup>-4</sup> for methylamine.
1) First, I multiplied 0.025 L with ... |
I want to know the differnce **between "delta G" and "delta G with a o on top"**? I couldn't figure it out.
Ex:
1. `delta G with o` = -RT ln k
2. `delta G` = `delta G with o` + RT ln k
What is the difference, is it that `delta G with o` is the value predicted by the standard free energies and that `delta g`... |
What is the difference between "delta G" and "delta G with a o on top"? |
I want to know the differnce between $\Delta\mathrm{G}$ and $\Delta\mathrm{G}$ **"with an o on top"**? I couldn't figure it out.
Ex:
1. $\Delta\mathrm{G}$ `with o` = -RT ln k
2. $\Delta\mathrm{G}$ = $\Delta\mathrm{G}$ `with o` + RT ln k
What is the difference, is it that $\Delta\mathrm{G}$ `with o` is the v... |
What is the difference between $\Delta\mathrm{G}$ and $\Delta\mathrm{G}$ "with an o on top"? |
I want to know the differnce between $\Delta\mathrm{G}$ and $\Delta\mathrm{G}$ **"with an o on top"**? I couldn't figure it out.
Ex:
1. $\Delta\mathrm{G}^{\circ}$= $-RT\ln K$
2. $\Delta\mathrm{G} = \Delta\mathrm{G}^{\circ} + RT \ln K$
What is the difference, is it that $\Delta\mathrm{G}$ `with o` is the va... |
What is the difference between ΔG and ΔG "with an o on top"? |
A simple explanation would be that the "o on top" denotes standard state and the one without the "o on top" denotes conditions that are not standard state. However, that may not allow you to "get it" so let's look at the equations.
1. $\Delta\mathrm{G}^{\circ}$= $-RT\ln K$
2. $\Delta\mathrm{G} = \Delta\mathrm{G}^{\... |
The molar heat of fusion of ice is 6.01 kJ/mol.
Can you explain what this means? What I think it means is that it requires 6.01 kJ to melt a mole of ice. I'm not positive though.. |
Molar heat of fusion of ice? |
> Cobalt exhibits a more specific interaction with histidine tags, resulting in less nonspecific interaction than nickel. For this reason, cobalt is the preferred divalent cation for purifying His-tagged proteins when high purity is a primary concern.
I read this last week, and I'm wondering, why is cobalt like that... |
Wikipedia says :
> The term gram-atom (abbreviated gat.) has been used for a related but distinct concept, namely a quantity of a substance that contains Avogadro's number of atoms, whether isolated or combined in molecules. Thus, for example, 1 mole of MgB2 is 1 gram-molecule of MgB2 but 3 gram-atoms of MgB2.
Ca... |
What exactly does gram atoms means? |
$\ce{MgB2}$ is 1 gram-molecule of $\ce{MgB2}$ but 3 gram-atoms of $\ce{MgB2}$.
Why is this so? Let us consider this problem in the familiar mole:
If we were asked how many moles of the substance (molecule) were in this, we would state 1 mole, if there were ${45.3g}$ of substance. However, if we were asked how man... |
I have read numerous online questions similar to the one I am about to ask. But for most of them the answer has been that the reason one can add water to the unknown concentration solution during a titration is because:
1) Water has a pH of 7
2) This is a volumetric analysis, so as long as one record the volume o... |
Whilst the Bohr model is incomplete and incorrect, it had limited usage in predicting spectral lines. In the same way, could it possibly with limited accuracy, be used to predict the outcome of chemical interactions to within "an order of magnitude" for which it was so famously known to do for many physical phenomena? |
Usefulness of the outdated Bohr model? |
What is the most commonly used radius of an atom or molecule to describe the area that must touch another area of another molecule for the two to react. Is there one radius that always works or does it depend on the reaction? Of course the actual distance at which bonds can form or break varies but I was wondering if a... |
The way to determine the van der Waals volume of an atom in a molecule (Therefore, the volume of the molecule) is by doing a quantum calculation to obtain the wave function and, then, integrate it.
You can obtain the volume of your desire molecule by following these steps:
1. Do a quantum calculation with the de... |
The way to determine the van der Waals volume of an atom in a molecule (Therefore, the volume of the molecule) is by doing a quantum calculation to obtain the wave function and, then, integrate it.
You can obtain the volume of your desire molecule by following these steps:
1. Do a quantum calculation with the de... |
I would like to understand the term stability in organic chemistry. How do we know that i-butane is more stable than n-butane? is it because of formation enthalpies or is there any other physical/ chemical explanation for this? thanks.. |
Why is i-butane more stable than n-butane? |
I would like to understand the term stability in organic chemistry. We know empirically that i-butane is more stable than n-butane.
But why is it more stable?
Is it because of formation enthalpies or is there any other physical/chemical explanation for this? |
I'm reading a paper about the atmospheric chemistry on Titan {1}. It quotes "column photochemical and loss rates" for various species in units of $\mathrm{cm^{-2}s^{-1}}$. These figures are the overall rates at which these species are generated photochemically according to a model, and I would like to convert them int... |
How do I interpret a flux quoted in $\mathrm{cm^{-2}s^{-1}}$ in atmospheric chemistry? |
I read about entropy from different sources. Still don't get why entropy change has to be greater than zero for a process which goes forward. Is it a result of pure observation or is there any theoretical background of this phenomena? |
why everything goes in the direction of positive entropy change? |
It is well known that single atom of oxygen is not stable, and it forms $\ce{O2}$ molecule. But elements like carbon form a network of repeated bonds. As answered in another [question][1], last atoms in such network are unstable and need to create some bonds.
Is it possible to have a (free-standing) single atom of c... |
Is a single carbon atom stable? |
I want to know the differnce between $\Delta G$ and $\Delta G$ **"with an o on top"**? I couldn't figure it out.
Ex:
1. $\Delta G^\circ$= $-RT\ln K$
2. $\Delta G = \Delta G^\circ + RT \ln K$
What is the difference, is it that $\Delta G^\circ$ is the value predicted by the standard free energies and that $\D... |
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