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> Is there a formal definition of the two terms?
One form of the fundamental equation of thermodynamics is:
$$\mathrm{d}U = T\mathrm{d}S - P \mathrm{d}V + \sum_{i}\mu_i \mathrm{d}N_i$$
In this equation, the total internal energy has canonical variables $V$, $S$, and $\mathrm{d}N_i$, where $S$ is the total entr... |
What's the difference between ΔG° and ΔG°'? |
> Is there a formal definition of the two terms?
One form of the fundamental equation of thermodynamics is:
$$\mathrm{d}U = T\,\mathrm{d}S - P\, \mathrm{d}V + \sum_{i}\mu_i \,\mathrm{d}N_i$$
In this equation, the total internal energy has canonical variables $V$, $S$, and $\mathrm{d}N_i$, where $S$ is the tota... |
How can I determine if a coordination compound has a tetrahedral or square planar geometry without any experimental data (such as magnetic spin) by just looking at its formula?
For example, what is the geometry of the following complexes:
- $\ce{[CoCl4]^2-}$
- $\ce{[Ni(CN)4]^2-}$
- $\ce{[CuCl4]^2-}$
Do t... |
This question pertains to the change of state of liquid using a Metering Device as the refrigerant enters an Evaporator Coil of an HVAC system:
[![enter image description here][1]][1]
The Metering Device takes liquid and then reduces the pressure and then spits out 75 percent liquid and 25 percent vapor. I don't ... |
Metering Device decreases pressure yet produces saturated liquid? |
Obviously, there are general stability arguments that can be made to estimate relative pKas, such as evaluating the stability of the conjugate base of an acid, or thinking about how polarized the bond to hydrogen is.
However, is there a theory that can be absolute and account for the many exceptions to the above gu... |
> Is there a formal definition of the two terms?
One form of the fundamental equation of thermodynamics is:
$$\mathrm{d}U = T\mathrm{d}S - P \mathrm{d}V + \sum_{i}\mu_i \mathrm{d}N_i$$
In this equation, the total internal energy has canonical variables $V$, $S$, and $\mathrm{d}N_i$, where $S$ is the total entr... |
> Is there a formal definition of the two terms?
One form of the fundamental equation of thermodynamics is:
$$dU = TdS - P dV + \sum_{i}\mu_i dN_i$$
In this equation, the total internal energy has canonical variables $V$, $S$, and $dN_i$, where $S$ is the total entropy (in units of $\frac{\mathrm J}{\mathrm K}... |
I was sent data for a molecule referred to as **1,2'-bis(4-aminophenoxy)benzene**. I haven't been able to figure out if that is a real molecule.
If I drop the prime, I know _1,2-bis(4-aminophenoxy)benzene_ should look like that:
> [![1,2-bis(4-aminophenoxy)benzene][1]][1]
and Google agrees. But with the prime,... |
How to conveniently separate Cd impurities from ZnO without contaminating it? |
I just wrote my chemistry exam a few hours ago. But was left with doubt over a question.
**Q.** Explain why the energy of an electron in an orbital is negative?
A. I wrote that from the following equation, $E_n = -R_h\left(1-\frac{1}{n^2}\right)$, we can see that the energy will always be negative.
Is my answe... |
Why is the energy of an electron always negative? |
I just wrote my chemistry exam a few hours ago. However, I am still confused about the following question:
>Why is the energy of an electron in an orbital always negative?
I wrote that from the following equation
$$E_n = -R_h\left(1-\frac{1}{n^2}\right),$$
we can see that the energy will always be negative.... |
First, a reminder that most scientific "laws" are convenient mathematical approximations. They aren't guaranteed to work for every case, and they aren't guaranteed to have underlying physical meaning.
In the case of the [Dulong-Petit Law][1]:
> Despite its simplicity, Dulong–Petit law offers fairly good prediction f... |
First, a reminder that most scientific "laws" are convenient mathematical approximations. They aren't guaranteed to work for every case, and they aren't guaranteed to have underlying physical meaning. As such, don't think of exceptions as "not obeying the law"; it's more correct to say that the law isn't obeying realit... |
First, a reminder that most [scientific "laws"][1] are only **convenient mathematical approximations**. They aren't guaranteed to work for every case, and they aren't guaranteed to have underlying physical meaning. As such, don't think of exceptions as "not obeying the law"; it's more correct to say that the law isn't ... |
My professor told us that for the sake of simplicity, we will assume that the order of reflection for Braggs' Law is always equal to 1 but failed to explain why. Is it because d(h,k,l) for materials has been determined using an order of reflection 1? |
Why is the order of reflection simplified to n = 1? |
Can someone explain this one, especially the formation of the secondary carbocation (in the solution)?
 |
Can someone explain this question? |
As for safety, calcium chloride, $\ce{CaCl2}$, is in sea water and [added to foods][1], such as beans and pickles. It's about as dangerous as table salt, sodium chloride, $\ce{NaCl}$ (actually, $\ce{CaCl2}$ is safer for concrete).
However, it absorbs only so much water until it dissolves and stops being effective. W... |
Can someone explain this one, especially the formation of the secondary carbocation (in the solution)?
> 
Solution:
> 
After the electrophilic attack by $\ce{H+}$ on the π bond, I had expected the carbonation f... |
Can someone explain 3‐(propan‐2‐yl)cyclohex‐1‐ene forming a carbocation? |
Be, Mg, Ba, Zn, Ni, Ca, Cu, Fe, Mn, Cd, Pb, Hg, Al carbonate salts are all insoluble.
I (perhaps naïvely) believe that I could precipitate carbonates from those mixing a soluble salts of these (e.g. CaCl2) with Na2CO3.
I (perhaps naïvely) believe that it would also work using NaHCO3, yielding CO2 and H2O as addit... |
Other than CO2 release, what are the disadvantages of precipitating metal carbonates using NaHCO3 instead of Na2CO3? |
In my basic organic chemistry class, I learned that only primary and secondary alcohols undergo oxidation (using KMnO4).
However, what is the outcome of reacting tertiary alcohol (1-methylcyclopentanol) with a strong oxidant like KMnO4 with no heat?
(P.S: I am specifically interested to know what happens with no heat... |
Can someone explain this one, especially the formation of the secondary carbocation (in the solution)?
> 
Solution:
> 
After the electrophilic attack by $\ce{H+}$ on the π bond, I had expected the carbocation f... |
Which is correct IUPAC name: chloromethylbenzene or chlorophenylmethane? I think it should be chloromethylbenzene because ring always gets priority over the chain unless a primary functional group is present. But the answer is chlorophenylmethane. Can you please explain? |
Which is correct IUPAC name: chloromethylbenzene or chlorophenylmethane? |
Why do processes like roasting and calcination require a temperature lower than the melting point? Since intermolecular forces are lower in a liquid won't it be easier to oxidise (roasting) / decompose (calcination) in this state than in a solid? |
Why does Freundlich adsorption isotherm does not have a term for the surface area ??
in the formula given by Freundlich adsorption isotherm that is given by
>$$ \frac{x}{m}= k P ^{1/n}$$
>Where "x" is the mass of gas adsorbed on mass "m" of the adsorbent and pressure "P". "k "and "n" are constants which depend on t... |
Why does Freundlich adsorption isotherm does not have a term for the surface area? |
The ratio
$$\frac{x}{m}= k P ^{1/n}$$
can be re-expressed in terms of the area $A$, surface-to-volume ratio $\lambda$, and density $\rho$ (note that $m=A\rho/\lambda)$:
$$\frac{x}{A}= k' P ^{1/n}$$
where
$$k'=k\rho/\lambda$$
The advantage of using $k$ as opposed to $k'$ is that you don't need to dete... |
The Balmer series, for example, is formed when the electron jumps from $n_2 = 3, 4, 5, \ldots, ∞$ to $n_1 = 2.$
The Humphry Davy series (The *last* series is formed when electron jumps from $n_2 = 7, 8, 9, \ldots, ∞$ to $n_1 = 6.$
Can't there be another series formed when electron jumps from $n_2 = 8,9,10... \ldo... |
Which is correct IUPAC name: chloromethylbenzene or chlorophenylmethane? I think it should be chloromethylbenzene because ring always gets priority over the chain unless a primary functional group is present. But the answer is chlorophenylmethane. Can you please explain? ![enter image description here](https://i.stack.... |
Why does Freundlich adsorption isotherm does not have a term for the surface area ??
in the formula given by Freundlich adsorption isotherm that is given by
>$$ \frac{x}{m}= k P ^{1/n}$$
>Where "x" is the mass of gas adsorbed on mass "m" of the adsorbent and pressure "P". "k "and "n" are constants which depend on t... |
In the image, the Rydberg constant seems to have two units. How is that possible?
 |
What is the unit of the Rydberg Constant? |
My book states that it depends upon "The number of photons of same frequency or wavelength ABSORBED or EMITTED"
From what I understood, if many hydrogen atoms within the discharge tube EMIT the **same wavelength**, then, on passing the radiation through a prism, these waves will **overlap** on the photographic plate (... |
What does Brightness/ intensity of spectral lines depend on? |
Why does the hexachlorocopper(II) ion not form? |
Why is halogenation of ketones in a base is "base promoted" and not "base catalysed" ?
I seek an answer with reference to the specific step in the mechanism , if the reaction is not "catalyzed" then how is the given base used up ? |
The ratio
$$\frac{x}{m}= k P ^{1/n}$$
can be re-expressed in terms of the area $A$, surface-to-volume ratio $\lambda$, and density $\rho$ (note that $m=A\rho/\lambda)$:
$$\frac{x}{A}= k' P ^{1/n}$$
where
$$k'=k\rho/\lambda$$
The advantage of using $k$ as opposed to $k'$ is that you don't need to dete... |
The ratio
$$\frac{x}{m}= k P ^{1/n}$$
can be re-expressed in terms of the area $A$, surface-to-volume ratio $\lambda$, and density $\rho$ (note that $m=A\rho/\lambda)$:
$$\frac{x}{A}= k' P ^{1/n}$$
where
$$k'=k\rho/\lambda$$
The advantage of using $k$ as opposed to $k'$ is that you don't need to dete... |
The ratio
$$\frac{x}{m}= k P ^{1/n}$$
can be re-expressed in terms of the area $A$, surface-to-volume ratio $\lambda$, and density $\rho$ (note that $m=A\rho/\lambda)$:
$$\frac{x}{A}= k' P ^{1/n}$$
where
$$k'=k\rho/\lambda$$
The advantage of using $k$ as opposed to $k'$ is that you don't need to dete... |
First, typically only high concentrations of chloride will interfere with the colorimetric test...I assume you are using NitraVer or something similar? If you aren't using seawater (i.e., Cl- > 100 mg/L) then you will be okay. But, let's say you are using seawater. There is an easy solution, simply make your standards ... |
I am used to thinking of exothermic reactions as being defined as having negative ∆H. However, I also am used to hearing/thinking of exothermic reactions as "releasing heat".
Since change in enthalpy ∆H = Q + V∆P, it seems that enthalpy and heat flow (Q) are not strictly the same thing. Is it not therefore possib... |
Exothermic: enthalpy or heat? |
Benzene has a molecular formula of C6H6 right? Surely it has some alkene like properties because of the double bonds, so can it undergo a hydration reaction to create alcohol? |
Does benzene react with steam to create an alcohol? |
Strange as it may seem, [benzene can be reached with steam over a suitable catalyst](https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.jstage.jst.go.jp/article/jpi1959/14/1/14_1_54/_pdf&ved=2ahUKEwi2w_L3zI3jAhWRWc0KHQzRB6AQFjABegQIBBAB&usg=AOvVaw3_pjoxniXW2cZjolyLu-uQ). The result is a complete breakdow... |
The overall reactions with the enthalpies of water electrolysis at room temperature can be represented by Equation below:
$$ 2H2O+237.2 kJ/mol+48.6 kJ/mol \to 2H2+O2 $$
Where 237.23 kJ/mol is the maximun electrical work can perform and should be calculated by:
$$\Delta H^。=0 kJ/mol-(-285.83 kJ/mol)=285.83 kJ/... |
How to calculate the value of heat absorption/ heat release during water electrolysis? |
I am used to thinking of exothermic reactions as being defined as having negative $ΔH.$ However, I also am used to hearing/thinking of exothermic reactions as "releasing heat".
Since change in enthalpy $∆H = Q + VΔP,$ it seems that enthalpy and heat flow $(Q)$ are not strictly the same thing. Is it not therefore ... |
The overall reactions with the enthalpies of water electrolysis at room temperature can be represented by the equation below:
$$\ce{2H2O + \pu{237.2 kJ mol-1} + \pu{48.6 kJ mol-1} → 2 H2 + O2}$$
Where $\pu{237.23 kJ mol-1}$ is the maximum electrical work can perform and should be calculated by:
$$
\begin{ali... |
What is the meaning of reduction and oxidation in organic chemistry?
In general chemistry I learned an **OIL RIG** mnemonic, i.e. oxidation is loss and reduction is gain (of electrons).
But what do we say about their usage in organic chemistry? I have seen their usage a lot of times in the form of reducing agents ... |
Benzene has a molecular formula of $\ce{C6H6},$ right? Surely it has some alkene-like properties because of the double bonds, so can it undergo a hydration reaction to create alcohol? |
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/4IbNC.jpg
When acetic acid looses hydrogen acetate, ion is formed which attacks 4-chlorobutene forming methyl butenoate. How does cyclic structure form?
does the lone pair of oxygen attacks butene internally? |
What is this fluorinated organic substance? |
First, typically only high concentrations of chloride will interfere with the colorimetric test...I assume you are using NitraVer or something similar? If you aren't using seawater (*i.e.*, $\ce{Cl-} \gt \pu{100 mg/L}$) then you will be okay. But, let's say you are using seawater. There is an easy solution, simply make... |
I'm wondering why radium appears to buck the general trend that first ionisation energies decrease as you move down a group in the periodic table: barium (the group 2 element preceding it) has a first ionisation energy of $\pu{502.9 kJ/mol}$, whereas radium has a slightly higher first I.E. of $\pu{509.3 kJ/mol}$ (from ... |
It is known that $\mathrm{S_N1}$ (Substitution Nucleophilic Unimolecular) follows the order of rate of reaction:
>Tertiary ($3^\circ$) > Secondary ($2^\circ$) > Primary ($1^\circ$)
For $\mathrm{S_N2}$ (Substitution Nucleophilic Bimolecular) the order of rate:
> Tertiary ($3^\circ$) < Secondary ($2^\circ$) < Pri... |
Why does Freundlich adsorption isotherm does not have a term for the surface area??
in the formula given by Freundlich adsorption isotherm that is given by
>$$ \frac{x}{m}= k P ^{1/n}$$
>Where $x$ is the mass of gas adsorbed on mass $m$ of the adsorbent and pressure $P$. $k$ and $n$ are constants which depend... |
The ratio
$$\frac{x}{m}= k P ^{1/n}$$
can be re-expressed in terms of the area $A$, surface-to-volume ratio $\lambda$, and density $\rho$ (note that $m=A\rho/\lambda)$:
$$\frac{x}{A}= k' P ^{1/n}$$
where
$$k'=k\rho/\lambda$$
The advantage of using $k$ as opposed to $k'$ is that you don't need to dete... |
In my basic organic chemistry class, I learned that only primary and secondary alcohols undergo oxidation (using $\ce{KMnO4}$).
However, what is the outcome of reacting tertiary alcohol (1-methylcyclopentanol) with a strong oxidant like $\ce{KMnO4}$ with no heat?
(P.S: I am specifically interested to know what happen... |
I have a protein that I purified in PBS buffer, pH 7. I will do dialysis to remove salt and will then further purify the protein with ion exchange chromatography.
I will need to use another buffer (Tris-HCl) with pH 8 in the chromatography, and so my question is:
Can I change the buffer system for my protein in th... |
Change buffer in dialysis? |
In my basic organic chemistry class, I learned that only primary and secondary alcohols undergo oxidation (using $\ce{KMnO4}$).
However, what is the outcome of reacting tertiary alcohol (1-methylcyclopentanol) with a strong oxidant like $\ce{KMnO4}$ with no heat?
P.S. I am specifically interested to know what hap... |
Wikipedia says polyimides are known for _“thermal stability, good chemical resistance, excellent mechanical properties”_. I guess that's why they're used industrially as fibers.
But where do they derive there good stability (thermal, mechanical and chemical) from? How do these properties differ from, e.g., polyamide... |
What makes polyimides good polymers for fibers? |
Which is the correct IUPAC name for this molecule: chloromethylbenzene or chlorophenylmethane?
I think it should be chloromethylbenzene because the ring always gets priority over the chain unless a primary functional group is pres... |
[![enter image description here][1]][1]
1,4-dimethylcyclohexane,
[1]: https://i.stack.imgur.com/mU1T6.png
I am having difficulty identifying the second product (is it an ether? a kind of epoxide?)therefore I am out of ideas on how to reach it.
However, I do have a general idea how to receive the first produ... |
I thought that the correct IUPAC name for the molecule below would be chloromethylbenzene because the ring always gets priority over the chain unless a primary functional group is present. However, it seems the correct name is chlorophenylmethane. Can someone explain why that is?
) would be chloromethylbenzene because the ring always gets priority over the chain unless a primary functional group is present. However, it seems the correct name is chlorophenylmethane. Can s... |
Why is halogenation of ketones in base described as being "base-promoted" and not "base-catalysed"?
If the reaction is not "catalyzed" then how is the base used up? |
How do we find the oxidation state of individual carbon in Mg3C2.Explain with the help of structure if possible.For the average oxidation number ,we can exploit the fact that the molecule will be electrically neutral,but what about the individual atoms of carbon? |
[![Oxidation of 1,4-dimethylcyclohexane][1]][1]
[1]: https://i.stack.imgur.com/mU1T6.png
I am having difficulty identifying the second product. Is it an ether, or a kind of epoxide? I am out of ideas on how to reach it.
However, I do have a general idea how to receive the first product, in the means of knowi... |
Is it true in assuming that a higher boiling/melting point means that an organic compound will be more soluble in water?
I'm trying to distinguish between the solubility of aldehydes vs. ketones based on boiling point. I received a question in a test today about it, comparing propanal with propanone, based solely on... |
I will use IEX chromatography to purify a protein and will then use a equilibration buffer Tris-HCl, pH 8 to set the start conditions for my column and optimize the binding of my protein. Then inject my sample and further on elute with the same buffer but with a salt gradient.
My sample will contain my protein as we... |
Do I have to change my sample buffer before IEX chromatography? |
> Which of the following has the highest molar conductivity?
>(A) Diaminedichloroplatinum (I)
>(B) Tetraamminedichlorocobalt (III) chloride
>(C) Potassium hexacyanoferrate (II)
> (D) Hexaaquochromium (II) bromide
So in this I since mobility depends on the size and charge and the number of particles, how can we det... |
Which of the following has the highest molar conductivity? |
I am currently studying for my organic chemistry exam, but there is one problem I do not understand. Unfortunately, I do not have any solutions.
See image for the problem.
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/ut6xw.jpg
My first thought was the Dienone-phenol-rearrangeme... |
>If $R_1$ and $R_2$ are the resistance of 2 solution of equal volume , then the conductance of the mixture in the same conductivity cell is ??
In general , I didn't grasp the meaning very well or the approach.
Like will we add the resistances as now both the solution are there to resist, or add the conductance or ... |
If $R_1$ and $R_2$ are the resistance of 2 solution of equal volume , then the conductance of the mixture in the same conductivity cell is? |
How do we find the oxidation state of individual carbon in Mg2C3.Explain with the help of structure if possible.For the average oxidation number ,we can exploit the fact that the molecule will be electrically neutral,but what about the individual atoms of carbon? |
How do we find the oxidation state of individual carbon in Mg3C2.Explain with the help of structure if possible.For the average oxidation number ,we can exploit the fact that the molecule will be electrically neutral,but what about the individual atoms of carbon? |
>"Since change in enthalpy ∆H = Q + VΔP, it seems that enthalpy and heat flow (Q) are not strictly the same thing."
First, note that, when you write "∆H = Q + VΔP," you are assuming the only type of work is PV-work. That's a reasonable assumption for these discussions. It's just important to make that assumption e... |
>"Since change in enthalpy ∆H = Q + VΔP, it seems that enthalpy and heat flow (Q) are not strictly the same thing."
First, note that, when you write "∆H = Q + VΔP," you are assuming the only type of work is PV-work. That's a reasonable assumption for these discussions. It's just important to make that assumption e... |
>"Since change in enthalpy ∆H = Q + VΔP, it seems that enthalpy and heat flow (Q) are not strictly the same thing."
First, note that, when you write "∆H = Q + VΔP," you are assuming the only type of work is PV-work. That's a reasonable assumption for these discussions. It's just important to make that assumption e... |
>"Since change in enthalpy ∆H = Q + VΔP, it seems that enthalpy and heat flow (Q) are not strictly the same thing."
First, note that, when you write "∆H = Q + VΔP," you are assuming the only type of work is PV-work. That's a reasonable assumption for these discussions. It's just important to make that assumption e... |
>"Since change in enthalpy ∆H = Q + VΔP, it seems that enthalpy and heat flow (Q) are not strictly the same thing."
First, note that, when you write "∆H = Q + VΔP," you are assuming the only type of work is PV-work. That's a reasonable assumption for these discussions. It's just important to make that assumption e... |
>"Since change in enthalpy ∆H = Q + VΔP, it seems that enthalpy and heat flow (Q) are not strictly the same thing."
First, note that, when you write "∆H = Q + VΔP," you are assuming the only type of work is PV-work. That's a reasonable assumption for these discussions. It's just important to make that assumption e... |
>"Since change in enthalpy ∆H = Q + VΔP, it seems that enthalpy and heat flow (Q) are not strictly the same thing."
First, note that, when you write "∆H = Q + VΔP," you are assuming the only type of work is PV-work. That's a reasonable assumption for these discussions. It's just important to make that assumption e... |
>"Since change in enthalpy ∆H = Q + VΔP, it seems that enthalpy and heat flow (Q) are not strictly the same thing."
First, note that, when you write "∆H = Q + VΔP," you are assuming the only type of work is PV-work. That's a reasonable assumption for these discussions. It's just important to make that assumption e... |
Historically, the Plimsoll symbol (aka Plimsoll line) was created as hull mark that would serve as a ready indicator of whether a ship was overloaded and thus running too low in the water. It was later adopted by chemists to indicate standard state (currently defined by IUPAC as 1 bar).
Why was the Plimsoll symbo... |
>If $R_1$ and $R_2$ are the resistances of two solutions of equal volume what is the conductance of the mixture in the same conductivity cell?
In general, I grasped neither the approach, nor the meaning very well.
Do we add the resistances as now both the solution are there to resist, or do we add the conductanc... |
>"Since change in enthalpy ∆H = Q + VΔP, it seems that enthalpy and heat flow (Q) are not strictly the same thing."
First, note that, when you write "∆H = Q + VΔP," you are assuming the only type of work is PV-work. That's a reasonable assumption for these discussions. It's just important to make that assumption e... |
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