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[![Photoelectric question][1]][1]
[1]: https://i.stack.imgur.com/7rNgw.png
My attempt:- 1)At 0.68e15 Hz frequency of light,Metal A gives 7.2eV Kinetic Energy(KE).
2)At 1e15 Hz frequency of light, Metal B, gives 6eV Kinetic Energy.
3) At 1.1e15 Hz frequency of light, Metal C gives 5.5eV Kinetic Energy.
... |
In my book it is given that first electron gain enthalpy is greater than second for elements. Should we compare the magnitudes in such cases or the actual numbers with signs? Does the same comparision hold with Electron Affinity at 0K?
For example Be has positive Electron Affinity and F has negative Electron Affinity.... |
This is a classic experiment.
On a plate with a little water place a candle and light it. Place a drinking glass over it. The light goes out while sucking up the water.
At least two things happen:
1. The oxygen O₂ is changed to CO₂
2. The air is heated up a few degrees
3. Water is sucked up
But then I tr... |
**Changes in volume**
The chemical reaction for burning a candle is something like this:
$$\ce{C25H52 + 38 O2(g) -> 25 CO2(g) + 26 H2O(g)}$$
For every 38 dioxygen molecules used, you are making 25 carbon dioxide molecules and 26 water molecules (which start out as a gas, but will condense once they reach an ar... |
How can I calculate Kp given Gibb's free energy? |
Using the following relations:
$\Delta{G}^⦵ = \Delta{H}^⦵ -T\Delta{S}^⦵$
$K_P = e^{\frac{-\Delta{G}^⦵}{RT}}$
How would you find the temperature at which $K_P = 1$?
>! $K_P = 1$ when $\frac{-\Delta{G}^⦵}{RT} = 0$, which is when $-\Delta{G}^⦵ = 0$
Given what $\Delta{G}^⦵$ must equal, how could you find T? |
Using the following relations:
$\Delta{G}^⦵ = \Delta{H}^⦵ -T\Delta{S}^⦵$
$K_P = e^{\frac{-\Delta{G}^⦵}{RT}}$
How would you find the temperature at which $K_P = 1$?
>! $K_P = 1$ when $\frac{-\Delta{G}^⦵}{RT} = 0$, which is when $\Delta{G}^⦵ = 0$
Given what $\Delta{G}^⦵$ must equal, how could you find T?
... |
Adding acids or bases to water, so that either pH or pOH decreases independently of the other, will that affect the auto-ionization of water? For example, pure water + auto-ionized state, with some base added to remove some protons, will it auto-ionize a bit more (create more H+ and OH-) or a bit less (remove some H+ a... |
Auto-ionization equilibrium of water shifted with acid-base addition? |
The problem is as follows:
> In a galvanic cell the cathode is an $Ag^{+}(1.00\,M)/Ag_{(s)}$
> half-cell. The anode is a standard hydrogen electrode immersed in a
> buffer solution containing $0.10\,M$ benzoic acid $(C_6H_5COOH)$ and
> $0.050\,M$ of sodium benzoate $(C_6H_5COO^{-}Na^{+})$. The measured
> cell vo... |
Does it exist a quick way to obtain the pKa of an acid in a galvanic cell other than having to work with a logarithm? |
The problem is as follows:
> In a galvanic cell the cathode is an $Ag^{+}(1.00\,M)/Ag_{(s)}$
> half-cell. The anode is a standard hydrogen electrode immersed in a
> buffer solution containing $0.10\,M$ benzoic acid $(C_6H_5COOH)$ and
> $0.050\,M$ of sodium benzoate $(C_6H_5COO^{-}Na^{+})$. The measured
> cell vo... |
It depends how you write the reaction.
> For example, pure water + auto-ionized state, with some base added to remove some protons, will it auto-ionize a bit more (create more H+ and OH-) or a bit less (remove some H+ and OH-)?
If we call the base $\ce{B}$ and the conjugate acid $\ce{BH+}$, you could write:
$$... |
Could someone please enlighten me on what would be the theoretical effect of a counter ion on the colour of the flame emmited by a metallic salt in a flame test?
Eg. NaCl - what would be the effect of the non metal on the general colour of the flame of the coumpond.
I am looking into specific groups of metallic salts... |
*Lacking an answer for 3 years, I'm going to attempt to answer this based on internet definitions and logic. Please, I welcome any insight from chemistry experts to improve this answer.*
First of all, the Wikipedia link quoted actually gives *two* definitions for protomer. The one quoted is the "structural biology" ... |
The article by Hu et al. \[[1](https://doi.org/10.1177/154405910608501212)\] mentions a compound "*dithreitol*" in the *Saliva Proteome Analysis* section (emphasis mine):
> For the "shotgun" approach, saliva samples (1 mL) were pre-fractionated with the use of Millipore ultracentrifuge filters (Millipore Corp., Bill... |
What is "dithreitol"? |
I've read at many places that temperature is the average kinetic energy of particles present in an object.I just don't get this intuitively how kinetic energy is connected with temperature?And how is heat connected with temperature then?then what exactly is temperature?All of the description given online is very confus... |
What exactly is temperature? |
I'm trying to create Copper (II) Acetate crystals, but in these times of Coronavirus it's difficult to come by hydrogen peroxide. I could be patient, but I'm not, so I'm trying to make it electrochemically. I have 5% vinegar and lots of copper scrap, and an adjustable power supply. Unfortunately I can't barely get any ... |
Heat is the transfer of energy to or from the body in forms other than matter flow or work (organized energy transfer, such as pushing).
Temperature is only a well-defined property for a collective body (you wouldn't be able to tell me the temperature of a single atom, for example). Like you said, it's the property ... |
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/28FIf.png
Here, when they write v/(mol s^-1 (kg protein)^-1) is 0.30 for the first row first column, do they mean that the value is 0.30 mol s^-1 (kg protein)^-1 or 0.30/(mol s^-1 (kg protein)^-1)?
|
I've read at many places that temperature is the average kinetic energy of particles present in an object. I just don't intuitively get how kinetic energy is connected with temperature. And how is heat connected with temperature then? Then what exactly is temperature? All of the descriptions given online are very confu... |
I'm studying 12th. In my book they mentioned that [Co(en)3]3+ exhibit optical isomerism. But in that same book, a choose is like this * Which of this doesn't exhibit isomerism * and it's answer is [Fe(en)3]3+. They both show same structure, then why they are saying [Fe(en)3]3+ don't show isomerism? |
Do [Fe(en)3]3+ exhibit optical isomerism? |
I'm studying 12th. In my book they mentioned that $\ce{[Co(en)3]^3+}$ exhibit optical isomerism.
But in that same book, a choose is like this:
> Which of this doesn't exhibit isomerism?
and the answer is $\ce{[Fe(en)3]^3+}.$ Since both complexes have the same structure, then why they are saying $\ce{[Fe(en)3]^... |
Does tris(ethylenediamine)iron(III) exhibit optical isomerism? |
I'm studying 12th. In my book they mentioned that $\ce{[Co(en)3]^3+}$ exhibits optical isomerism.
But in that same book, there is a question
> Which of this doesn't exhibit isomerism?
and the answer is $\ce{[Fe(en)3]^3+}.$ Since both complexes have the same structure, then why they are saying $\ce{[Fe(en)3]^3+... |
The article by Hu et al. \[[1](https://doi.org/10.1177/154405910608501212)\] mentions a compound "*dithreitol*" in the *Saliva Proteome Analysis* section (emphasis mine):
> For the "shotgun" approach, saliva samples (1 mL) were pre-fractionated with the use of Millipore ultracentrifuge filters (Millipore Corp., Bill... |
Recall the flame emission experiment is basically an *atomic* emission experiment. We don't say it is a compound emission experiment. The job of the flame/plsama or any high temperature medium is to decompose the compound into the constituent atoms or even ions for an experiment. Once a dilute metal salt solution is as... |
Could someone please enlighten me on what would be the theoretical effect of a counter ion on the colour of the flame emitted by a metallic salt in a flame test?
Eg. NaCl - what would be the effect of the non-metal on the general colour of the flame of the compound?
I am looking into specific groups of metallic sal... |
$\newcommand{\Ket}[1]{\left|#1\right>}$
$\newcommand{\Bra}[1]{\left<#1\right|}$
$\newcommand{\BraKet}[2]{{\left<#1}\left|#2\right>}$
It's an older question, but one worth answering!
For the uninitiated, second quantization is a bookkeeping technique that describes many-particle systems as excited states of a ... |
$\newcommand{\Ket}[1]{\left|#1\right>}$
$\newcommand{\Bra}[1]{\left<#1\right|}$
I'm currently revising for my qualifiers, and I've come across a point of confusion, one that several places give seemingly contradictory results.
To my understanding:
In Hartree-Fock, the variationally determined ground state, $... |
Are Hartree-Fock solutions eigenfunctions of the electronic hamiltonian? |
Why do most people want to believe that on burning fuel little or no carbon monoxide is created?
Yes, it could be true, mainly CO2 is formed, but read these qualifying [comments from a source](https://www.abe.iastate.edu/extension-and-outreach/carbon-monoxide-poisoning-checking-for-complete-combustion-aen-175/):
... |
**Temperature vs kinetic energy**
>[OP:] I've read at many places that temperature is the average kinetic energy of particles present in an object.
Temperature has to do with the average kinetic energy of particles, but to say the two concepts are the same is incorrect. What is correct is that if the particles in... |
Why do most people want to believe that on burning fuel little or no carbon monoxide is created?
Yes, it could be true, mainly CO2 is formed, but read these qualifying [comments from a source](https://www.abe.iastate.edu/extension-and-outreach/carbon-monoxide-poisoning-checking-for-complete-combustion-aen-175/):
... |
**Temperature vs kinetic energy**
>[OP:] I've read at many places that temperature is the average kinetic energy of particles present in an object.
Temperature has to do with the average kinetic energy of particles, but to say the two concepts are the same is incorrect. What is correct is that if the particles in... |
Why do most people want to believe that on burning fuel little or no carbon monoxide is created?
Yes, it could be true, mainly CO2 is formed, but read these qualifying [comments from a source](https://www.abe.iastate.edu/extension-and-outreach/carbon-monoxide-poisoning-checking-for-complete-combustion-aen-175/):
... |
I'm sorry this is probably a ridiculous question. I surprisingly could not find the answer from googling.. also sorry about the tags I couldn't find better ones.
Is this the correct way to write an uncertain measurement of 0.75 mL that might be between 0.7 mL and 0.8 mL?:
0.75 mL ± 0.05 mL
Thanks |
How do I write a measurement with a margin of error using ±? |
Is this the correct way to write an uncertain measurement of 0.75 mL that might be between 0.7 mL and 0.8 mL?:
0.75 mL ± 0.05 mL |
>To calculate $\Delta H$, the change in enthalpy at $\mathrm{100^\circ C}$ for the reaction below, one needs what addition information?
>$$\ce{N2(g) + 3H2(g) -> 2NH3(g)}$$
>$\Delta H^\circ = \pu{-92.0 kJ}$ at $\mathrm{25^\circ C}$
> (a) The equilibrium constant for the reaction at $\mathrm{100^\circ
C}$
... |
I am currently conducting an experiment into the glucose content of certain sports drinks. However, I have hit a roadblock. A majority of the drinks that I intend to test, contain sucrose. I am thinking that by adding $\pu{1.0M~ HCl}$, to say, $\pu{100mL}$ of solution (sports drink), it will decompose the sucrose into ... |
Here is a partial answer with a quantitative description of how the hydration enthalpy could impact the electrode potential. In particular, select salts can undergo hydrolysis resulting in the liberation of H+, for example with copper or iron:
> $\ce{Fe[(H2O)6](3+) (aq) + H2O (l) = [Fe(H2O)5(OH)](2+) (aq) + H3O+ (aq... |
I'm having trouble understanding why the top SN2 reaction proceeds faster. I know that benzylic and allylic halides react faster in SN2 reactions than non-conjugated halides. I think it's because the transition state is more stable but how can you explain that using MO Theory?
[![m][1]][1]
> This is what my pro... |
Why is the top SN2 reaction faster? (Molecular Orbital Theory) |
If 40.0 grams of Aluminum and 25.0 gram of Cl2 reacted together how much AlCl3 can be produced? |
I'm trying to migrate away from Gaussian09, using Gamess-US instead for molecular modelling of some heavy alkaline earth metal complexes, using density functional theory(DFT). In some of my previous Gaussian inputs I used the [SDD][1] (Stuttgard/Dresden) pseudopotential with the metallic cátion(Sr+2). Now I intend to r... |
How to reproduce Gaussian09 SDD pseudopotential in Gamess-US? |
First, an answer providing a quantitative description of how the hydration enthalpy could impact the electrode potential. In particular, select salts can undergo hydrolysis resulting in the liberation of H+, for example with copper or iron:
> $\ce{Fe[(H2O)6](3+) (aq) + H2O (l) = [Fe(H2O)5(OH)](2+) (aq) + H3O+ (aq)}$... |
First, I present an example, which provides a quantitative description of how the hydration enthalpy could impact the electrode potential. In particular, select salts can undergo hydrolysis resulting in the liberation of H+, for example with copper or iron:
> $\ce{Fe[(H2O)6](3+) (aq) + H2O (l) = [Fe(H2O)5(OH)](2+) (... |
First, I present an example, which provides a quantitative description of how the hydration enthalpy could impact the electrode potential. In particular, select salts can undergo hydrolysis resulting in the liberation of H+, for example with copper or iron:
> $\ce{Fe[(H2O)6](3+) (aq) + H2O (l) = [Fe(H2O)5(OH)](2+) (... |
I did some research. Found some semiempirical methods that work even with heavy lanthanide compounds ([RM1][1]). But could not find any references to semiempirical methods compatible with the heavier members of the alkali earth group: Sr, Ba and Ra. If there is such method, does any open source / free software implemen... |
Are there any semiempirical methods that work with heavy alkaline earth metals? |
I’m designing an experiment which requires I measure final and initial lead concentrations for the determination of aqueous lead uptake by different mediums. Because lead concentrations would be measured on the ppm scale, I’d need to use a spectrophotometer to measure light absorbance by the water samplings. I could th... |
First, I present an example, which provides a quantitative description of how the hydration enthalpy could impact the electrode potential. In particular, select salts can undergo hydrolysis resulting in the liberation of H+, for example with copper or iron:
> $\ce{Fe[(H2O)6](3+) (aq) + H2O (l) = [Fe(H2O)5(OH)](2+) (... |
I'm trying to migrate away from Gaussian09, using Gamess-US instead for molecular modelling of some heavy alkaline earth metal complexes, using density functional theory (DFT). In some of my previous Gaussian inputs I used the [SDD][1] (Stuttgard/Dresden) pseudopotential with the metallic cation ($\ce{Sr^{+2}}$). Now I... |
>In my book it is given that first electron gain enthalpy is greater than second for elements. Should we compare the magnitudes in such cases or the actual numbers with signs?
###Successive Electron Gain Enthalpies
After the addition of one electron atom becomes negatively charged and second electron is to be added... |
>In my book it is given that first electron gain enthalpy is greater than second for elements. Should we compare the magnitudes in such cases or the actual numbers with signs?
###Successive Electron Gain Enthalpies
After the addition of one electron atom becomes negatively charged and second electron is to be added... |
>In my book it is given that first electron gain enthalpy is greater than second for elements. Should we compare the magnitudes in such cases or the actual numbers with signs?
###Successive Electron Gain Enthalpies
After the addition of one electron atom becomes negatively charged and second electron is to be added... |
>In my book it is given that first electron gain enthalpy is greater than second for elements. Should we compare the magnitudes in such cases or the actual numbers with signs?
###Successive Electron Gain Enthalpies
After the addition of one electron atom becomes negatively charged and second electron is to be added... |
>In my book it is given that first electron gain enthalpy is greater than second for elements. Should we compare the magnitudes in such cases or the actual numbers with signs?
###Successive Electron Gain Enthalpies
After the addition of one electron atom becomes negatively charged and second electron is to be added... |
I am asked to determine what is the O.S. of oxygen in $\ce{Na2O2}$
I was under the impression that oxygen had a charge of -2 and I multiplied that charge by 2 giving me a total of -4.
However, the computer program I am using, states that I am wrong. Can someone clarify why? |
What is the oxidation state of oxygen in Na2O2? |
Another possibility is the grease spot photometer (aka Bunsen photometer) [German Wiki page](https://de.wikipedia.org/wiki/Fettfleck-Photometer). This can be homemade, you need a piece of paper, some wax or oil, two light sources, a meter stick and for the measurement of solutions also some e.g. cardboard to shield unw... |
Another possibility is the **grease spot photometer** (aka Bunsen photometer) [German Wiki page](https://de.wikipedia.org/wiki/Fettfleck-Photometer). This can be homemade, you need a piece of paper, some wax or oil, two light sources, a meter stick and for the measurement of solutions also some e.g. cardboard to shield... |
The $CO$ triple bond has a bond enthalpy of 1072 kJ/mol while the $N_2$ 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, including
>... |
Why is the carbon monoxide triple bond stronger than the nitrogen-nitrogen triple bond? |
Another possibility is the **grease spot photometer** (aka Bunsen photometer) [German Wiki page](https://de.wikipedia.org/wiki/Fettfleck-Photometer). This can be homemade, you need a piece of paper, some wax or oil, two light sources, a meter stick and for the measurement of solutions also some e.g. cardboard to shield... |
Another possibility is the **grease spot photometer** (aka Bunsen photometer) [German Wiki page](https://de.wikipedia.org/wiki/Fettfleck-Photometer). This can be homemade, you need a piece of paper, some wax or oil, two light sources, a meter stick and for the measurement of solutions also some e.g. cardboard to shield... |
$\newcommand{\ket}[1]{\left|#1\right>}$
$\newcommand{\bra}[1]{\left<#1\right|}$
> (1) Is this all correct so far?
Yep.
> (2) If so, is it justified to use it in numerical derivations as an
> eigenfunction of the Hamiltonian, i.e. can we write
> $\hat{H}\ket\Phi\overset{?}{=}E_{0}\ket\Phi$ or are we restricted... |
$\newcommand{\ket}[1]{\left|#1\right>}$
$\newcommand{\bra}[1]{\left<#1\right|}$
> (1) Is this all correct so far?
Yep.
> (2) If so, is it justified to use it in numerical derivations as an
> eigenfunction of the Hamiltonian, i.e. can we write
> $\hat{H}\ket\Phi\overset{?}{=}E_{0}\ket\Phi$ or are we restricted... |
I have a compound, dimethylaminoethanol (DMAE) bitartrate, which I originally purchased as a supplement and possible smart drug. I bought an absurd amount of it. It didn’t do anything for me as a supplement. I understand that DMAE, not the bitartrate salt, is commonly used in cosmetics, & I’d like to play with it for t... |
How can I remove the bitartrate anion from an organic bitartrate salt? |
The problem is as follows:
> In a galvanic cell the cathode is an $Ag^{+}(1.00\,M)/Ag_{(s)}$
> half-cell. The anode is a standard hydrogen electrode immersed in a
> buffer solution containing $0.10\,M$ benzoic acid $(C_6H_5COOH)$ and
> $0.050\,M$ of sodium benzoate $(C_6H_5COO^{-}Na^{+})$. The measured
> cell vo... |
Perhaps you can add H2S to create PbS (as a starting step). Then, based on an extract from Wikipedia on Lead Sulfide:
>Although of little commercial value, PbS is one of the oldest and most common detection element materials in various infrared detectors.[12] As an infrared detector, PbS functions as a photon detect... |
Take $\rm NaCl$ for instance, a salt that will melt when it reaches its melting point, and compare it with $\rm NH_4NO_3$, a salt that doesn't melt, but instead decomposes to $\rm N_2O$ and $\rm H_2O$ on heating to a high enough temperature.
How can we determine if a salt will simply melt, or if it will decompose o... |
How can we tell if a salt will melt or decompose? |
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