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What is the precipitate of this reaction of magnesium? |
Solid $\ce{NaHCO3}$ is heated to 90°C. At equilibrium the total pressure of the gases produced is 0.545 atm. Calculate $\ce{ΔG°}$ at 90°C for the reaction
$\ce{2 NaHCO3(s) ⇌ Na2CO3(s) + H2O(g) + CO2(g)}$
Using the $\ce{∆G° = -R*T*ln(K)}$ formula, I did the work below:
$\ce{∆G°}$ = -(8.31)(273.15+90)*ln(0.545)
... |
The minimum pressure for the existence of liquid solution is
(1) $0.6 atm$
(2) $0.8 atm$
(3) $0.77 atm$
(4) $0.9 atm$
Although this seems to be an informative question , i want to know how do we get this??
I know that the critical pressure for a liquid solution is $p={ a\over {27b^2}}$ but w... |
Solid $\ce{NaHCO3}$ is heated to 90°C. At equilibrium the total pressure of the gases produced is 0.545 atm. Calculate $\ce{ΔG°}$ at 90°C for the reaction
$\ce{2 NaHCO3(s) ⇌ Na2CO3(s) + H2O(g) + CO2(g)}$
Using the $\ce{∆G° = -R*T*ln(K)}$ formula, I did the work below:
$\ce{∆G°}$ = $-(8.31)(273.15+90)\ce{*}ln(0... |
The minimum pressure for the existence of liquid solution is
(1) $0.6\; atm$
(2) $0.8\; atm$
(3) $0.77\; atm$
(4) $0.9\; atm$
Although this seems to be an informative question, I want to know the process by which we get this answer.
I know that the critical pressure for a liquid solution is ... |
What is the minimum pressure for existence of a liquid solution? |
Which d-block cation has the maximum hydration enthalpy? |
The only things I can figure for $a$ and $b$ in $p=\dfrac{a}{27b^2}$ are the coefficients from the [van der Waals equation](http://en.wikipedia.org/wiki/Van_der_Waals_equation) for nonideal gases:
$$\left(p+\dfrac{n^2a}{V^2}\right)\left(V-nb\right)=nRT$$
These constants have appropriate units to give you pressure... |
For your reaction:
$$\ce{2 NaHCO3(s) ⇌ Na2CO3(s) + H2O(g) + CO2(g)}$$
$$K=P_{\ce{CO2}}\cdot P_{\ce{H2O}}$$
However, $K\ne0.545\text{ atm}$ because the **sum** of the pressures is $0.545\text{ atm}$ and the equilibrium constant is the **product** of the pressures.
$$P_{\ce{CO2}}+P_{\ce{H2O}}=0.545\text{ atm}... |
Molecules possessing a bond of order below 1 can be perfectly stable, in the sense that their resulting molecular structure lies in an energetic potential well. Strictly speaking it is enough that at $T=0\ K$ and in the absence of any interactions with matter or fields, the molecule will not spontaneously disassemble. ... |
I'm a enthusiastic and devoted amateur chemist (in disguise, I'm actually a mathematician), but lately I've been thinking to what extend it is safe to pursue my hobby. I'm after all an amateur with just high-school lab skills and some unnecessary math to back me up. I really love chemical experiments, but I don't want ... |
Molecules possessing a bond of order below 1 can be perfectly stable, in the sense that their resulting molecular structure lies in an energetic potential well. Strictly speaking it is enough that at $T=0\ K$ and in the absence of any interactions with matter or fields, the molecule will not spontaneously disassemble. ... |
With $\ce{(NH4)2HPO4}$, $\ce{Mg^2+}$ forms a white, crystalline precipitate of [magnesium ammonium phosphate hexahydrate][1]:
$$\ce{Mg^2+ + HPO4^2- + NH4^+ + OH- + 5H2O \rightleftharpoons Mg(NH4)PO4 \cdot 6H2O\downarrow}$$
This is a very sensitive test for $\ce{Mg^2+}$; however, calcium, strontium, barium and oth... |
Combustion of 0.2000g of vitamin C gives 0.2998g CO^2 and 0.819g of water.What is emperical formula of vitamin C?
My work:-
I calculated moles of products and found mole ratio but its not coming to be a whole number. HELP! |
Let's consider the five-atom ring part of the histidine molecule.
![enter image description here][1]
I was wondering why only one of the lone pairs on nitrogen is involved in the delocalized pi system. Specifically, I was wondering why it is that lone pair in particular instead of the other lone pair (there ar... |
Combustion of 0.2000 g of vitamin C gives 0.2998 g $\ce{CO2}$ and 0.819 g of water. What is the empirical formula of vitamin C?
My work:
I calculated moles of products and found the mole ratio but it's not coming to be a whole number. Please help me! |
Combustion of 0.2000 g of vitamin C gives 0.2998 g $\ce{CO2}$ and 0.819 g of water. What is the empirical formula of vitamin C?
My work:
I calculated moles of products and found the mole ratio but it's not coming to be a whole number. |
Somewhere along the line of researching why the _Cl-C-H_ bond angle in methyl chloride is less than what is predicted (109.5 degrees), I ran into a book which said that the electron withdrawing effects of the chlorine atom gave the _C-Cl_ bond more _"p-character"_.
What does this mean? Is he simply using this term ... |
S orbitals are lower in energy than P orbitals. Electrons prefer to be in as low an energy orbital as possible. Therefor, when we mix S and P orbitals to make hybrid orbitals, the more S character the orbital has the lower the energy of electrons occupying that orbital. In the methyl chloride case, the chlorine atom ... |
S orbitals are lower in energy than P orbitals. Electrons prefer to be in as low an energy orbital as possible. Therefor, when we mix S and P orbitals to make hybrid orbitals, the more S character the orbital has the lower the energy of electrons occupying that orbital. Let me use chloroform, $\ce{CHCl3}$, as an exam... |
I've a question such as:
> 2 KOH(l) + H3PO4(l) -> K2HPO4(l) + 2 H2O(l) at STP
> How many mL of H2O is produced?
Most questions I've found have more information than this so I'm confused as to how to do this problem.
I've tried multiplying 2 moles of H2O by 22.4L and then converting it to mL, but I've a... |
How many mL (or L) of x is produced when only given the equation at STP? |
With regard to a trigonal bipyramidal molecule, such as $\ce{PIBrClF}$, can there be any constituional isomers? I'm thinking no, because constitutional isomers differ in the connectivity of their atoms. The molecule only has single bonds. All are bound to a single central atom. There is no way for the connectivity of t... |
Constitutional Isomers or Stereoisomers? |
Correct, no constitutional isomers, but there are stereoisomers (different substituents in the apical and equatorial positions). Just for the record, what is your fifth substituent? |
With regard to a trigonal bipyramidal molecule, such as $\ce{PIBrClF_2}$, can there be any constituional isomers? I'm thinking no, because constitutional isomers differ in the connectivity of their atoms. The molecule only has single bonds. All are bound to a single central atom. There is no way for the connectivity of... |
Are these all valid isomers for the formula $\ce{C_3H_8O}$? I drew the first five; my friend came up with the last three, which have double bonds. Are these all isomers or different? More importantly, are there any more?
Also in general, how can one come up with all the isomers for a molecule? I heard of graph theo... |
Are these all valid isomers for the formula $\ce{C_3H_6O}$? I drew the first five; my friend came up with the last three, which have double bonds. Are these all isomers or different? More importantly, are there any more?
Also in general, how can one come up with all the isomers for a molecule? I heard of graph theo... |
How does a scientist from 19th century to 1920s able to measure the spectroscopy of chemicals?
It is known that there are almost no electronics or computers at that time |
How does a scientist from 19th century to 1920s able to measure the spectroscopy of chemicals? |
How does a scientist from 19th century to 1920s able to get the spectroscopy of chemicals?
It is known that there are almost no electronics or computers at that time |
How does a scientist from 19th century to 1920s able to get the spectroscopy of chemicals? |
How does scientist able to produce the accurate diagram for the structure of chemicals way before scientists capture the first images of molecules?
Reference: http://www.sciencedaily.com/releases/2013/05/130530142007.htm |
How does a scientist from 19th century to 1920s able to get the spectroscopy of chemicals?
It is known that there are almost no electronics or computers at that time
Any video link or reference link are much appreciated here. |
After consulting three organic chemistry texts (Wade, Klein, and Brown), only one actually clearly delineates a few guidelines for picking the most significant resonance structure. The others mention the same factors (maybe less one or two). So in sum, the important factors to consider are:
1) A filled valance shell... |
After consulting three organic chemistry texts (Wade, Klein, and Brown), only one actually clearly delineates a few guidelines for picking the most significant resonance structure. The others mention the same factors (maybe less one or two). So in sum, the important factors to consider are:
1) A filled valance shell... |
I've a question such as:
> $\ce{2 KOH(l) + H3PO4(l) \rightarrow K2HPO4(l) + 2 H2O(l)}$ at STP
> How many mL of $\ce{H2O}$ is produced?
Most questions I've found have more information than this so I'm confused as to how to do this problem.
I've tried multiplying 2 moles of $\ce{H2O}$ by 22.4 L and then ... |
After consulting three organic chemistry texts (Wade, Klein, and Brown), only one actually clearly delineates a few guidelines for picking the most significant resonance structure. The others mention the same factors (maybe less one or two). So in sum, the important factors to consider are:
1) A filled valance shell... |
The fourth principle of Molecular Orbitals state that:
Molecular orbitals are best formed when composed of Atomic orbitals of like energies.
I'm not sure about how I should interpret this; which is the correct?
- It means that the molecular orbitals that I need to consider are the ones formed by the same ... |
How would such a scientist be able to get the spectroscopy of chemicals? Without access to modern computing or electronics how would it be possible?
Any video link or reference link are much appreciated here. |
How could a scientist from the 19th or 20th century run the spectroscopy of chemicals? |
How were scientists able to produce these accurate structural diagrams long before scientists were able to capture images of the actual molecules?
Reference: [Scientists capture first images of molecules before and after reaction](http://www.sciencedaily.com/releases/2013/05/130530142007.htm) |
How could scientists produce accurate chemical structures before they could capture images of molecules? |
![enter image description here][1]
[1]: https://i.stack.imgur.com/QbiLF.png
Regarding the above picture, why is the C-C sigma bond composed of two $\ce{sp^2}$ orbitals while the C-H sigma bonds composed of $\ce{sp^3}$ hybrid orbitals? I don't see why; I thought the geometry around the carbons was trigonal pla... |
The standard electrode potentials for the following redox couples are given as:
$E_0(\ce{Fe^{2+}/Fe}) = x~\mathrm{V},$
$ E_0(\ce{Fe^{3+}/Fe^{2+}}) = y~\mathrm{V}$
What will be potential $E_0(\ce{Fe^{3+}/Fe})$ (in $\mathrm{V}$)?
My approach: $\ce{Fe^{3+} + e- + Fe^{2+} + 2e- -> Fe^{2+} + Fe}$
So $E_0(\ce{... |
In formamide, the nitrogens appear to be $\ce{sp^3}$ hybridized, implying tetrahedral geometry. However, analysis shows that the molecule is actually very nearly planar with bond angles close to 120 degrees.
I'm thinking this has to do with the partial double bond character in the molecule (also appears to be some ... |
![enter image description here][1]
Regarding the above picture, why is the C-C sigma bond composed of two $\ce{sp^2}$ orbitals while the C-H sigma bonds composed of $\ce{sp^3}$ hybrid orbitals? I don't see why; I thought the geometry around the carbons was trigonal planar. Why does hybridization differ across atom... |
In formamide, the nitrogens appear to be $\ce{sp^3}$ hybridized, implying tetrahedral geometry. However, analysis shows that the molecule is actually very nearly planar with bond angles close to 120 degrees.
EDIT: as suggested by Martin and another poster, hybridization is a rough concept. So perhaps the hybridizat... |
![enter image description here][1]
Regarding the above picture, why is the C-C $\sigma$ bond composed of two $\ce{sp^2}$ orbitals while the C-H $\sigma$ bonds composed of $\ce{sp^3}$ hybrid orbitals? I don't see why; I thought the geometry around the carbons was trigonal planar. Why does hybridization differ acros... |
Is this textbook bonding picture of hybridization in ethene wrong? |
After studying ionic equilibrium, I was just making some wild questions and I was unable to calculate the $\ce{pH}$ of this solution. Assume, ! mole of each was added to $1L$ solution of water.
My attempt :
$\ce{CH3COOH}+\ce{NH4OH<=>CH3COONH4}+\ce{H2O}$
This reaction will happen till all $\ce{CH3COOH}$ is co... |
After studying ionic equilibrium, I was just making some wild questions and I was unable to calculate the $\ce{pH}$ of this solution. Assume, 1 mole of each was added to $1L$ solution of water.
My attempt :
$\ce{CH3COOH}+\ce{NH4OH<=>CH3COONH4}+\ce{H2O}$
This reaction will happen till all $\ce{CH3COOH}$ is co... |
This tag is for questions looking for a single specific, or a small number of (citable) references.
Questions of the form "What paper/book reported the mechanism of X?", "Where can I find the original publication of synthesis X?", "Where can I find popular applications of catalyst X?", or "Where is the crystal stru... |
I am having trouble with a problem involving a Semi-infinite potential square well:
I have written down some notes that I added to the post. I have problems understanding the physical situation. See the figure in the notes. When the potential is just shifted upwards, so that the $V(x)=0$ region is $0<x<a$, I have no... |
You have some mistaken assumptions.
$\ce{NH4OH}$ and $\ce{CH3COONH4}$ are not molecules that exist.
The assuption "all $\ce{CH3COOH}$ is consumed" is incorrect.
Why do you say more $\ce{NH4OH}$ will be formed? How is this possibe? What can it be formed from?
Review that [Henderson–Hasselbalch equation]... |
How could a scientist from the 1800s to the 1920s run spectroscopy of chemicals? |
Is visible spectroscopy the only non-electronic method of all the spectroscopy method?
I know some of the spectroscopy method is possible being used because of electronics. |
Is visible spectroscopy the only non-electronic method of all the spectroscopy method? |
I don't think that cyclohexenone should have any resonance forms. Moving the double bond around would necessitate moving hydrogens around as well. That being said, is there a easier way to determine if a resonance form of a cyclic compound is valid? Drawing out each individual atom and bond is time-consuming!
![ent... |
I don't think that cyclohexenone should have any resonance forms. Moving the double bond around would necessitate moving hydrogens around as well. For example, I know that benzene exhibits resonance (duh) and the second picture attached shows the pi bonding electrons shifting but doesn't show any hydrogens shifting pos... |
I'm not sure you did do the experiment wrong. I performed this experiment and it closely matched this [video][1] which had a light yellow liquid and foam.
Here are my results
![After first filtration][2]
I filtered it a couple more times to remove more foam. Then added the aluminum foil.
![After aluminum fo... |
I haven't taken a chemistry class in several years, and I have honestly been searching the web for the past hour and can't find anything. I know this is something basic we learned back in high school chemistry but maybe I am not searching for the right term...
Is there a formula? I know how to calculate distillation... |
What is the formula for heat of vaporization under reduced pressure? |
[Link to exam][1]
> Which metal reacts most vigorously with water?
>(A) Ca (B) K (C) Mg (D) Na
The given answer is B and the reasoning is that is is the most electropositive since it the furthest left and down according to periodic trends.
However, isn't $\ce{K}$ the conjugate base from a strong base -- $\... |
[Link to exam][1]
> Which metal reacts most vigorously with water?
>(A) Ca (B) K (C) Mg (D) Na
The given answer is B and the reasoning is that is is the most electropositive since it the furthest left and down according to periodic trends.
However, isn't $\ce{K}$ the conjugate acid from a strong base -- $\... |
I understand what causes elements to be conductive or nonconductive. But what causes a substance say rubber to be nonconductive at a molecular level? |
I have never seen anything other than a set of rules like these when textbooks present how to assign oxidation numbers. Such as these:
![enter image description here][1]
[1]: https://i.stack.imgur.com/YlxeX.png
However, if we keep in mind that oxidation numbers are simply imaginary numbers which suppose a... |
Please read ron's post before continuing here (too long for a comment). Its reasoning is very good and makes a lot of sense. The activation barrier is the defining component for how vigorously components react.
His presented reaction may cover the initial activation barrier, but subsequent reactions also have to be... |
[Link to exam][1]
> Which metal reacts most vigorously with water?
>(A) Ca (B) K (C) Mg (D) Na
The given answer is B and the reasoning is that is is the most electropositive since it the furthest left and down according to periodic trends.
However, isn't $\ce{K}$ the conjugate acid from a strong base -- $\... |
Why does potassium react the most vigorously with water? |
I am perparing for a presentation on the application of TiO2 nanotubes in cement which is a recent topic in cement chemistry. Do you happen to have any papers (or know of any accessible on Internet) on the topic from the recent years that you can share with me? Or even if you have any information/experience to share, I... |
What is the colour of elemental Ag, I have doubt whether it is black or silver in colour--
</br>
* In Tollen's test we get a silvery precipitate of elemental silver.- Hence silver in colour.
* I have read somewhere and also the following links as a reference to that it was not mere speculations
http://books... |
What is the colour of elemental Ag? I have doubt whether it is black or silver in colour.
</br>
* In Tollens' test, we get a silvery precipitate of elemental silver - hence silver in colour.
* I have read somewhere and also in the following links as a reference that it was not mere speculation
http://books.... |
This is the gas-phase structure of hypofluorous acid:
![enter image description here][1]
[1]: https://i.stack.imgur.com/mVkLj.png
The solid-phase structure however has a bond angle of 101 degrees. Why is there a difference in the solid and gas phase bond angles?
Is this due to packing in the solid-phas... |
If I have the amount of the molecule in moles, how do I calculate the mass of an individual molecule? |
If I have the amount of the molecule in moles, how do I calculate the mass of an individual molecule?
For example, if the molecule was water? |
The "amount of molecules in moles", such as 7 moles, provides no information concerning the mass of an individual molecule.
This is like asking, "if I have the amount of eggs in dozens, how do I calculate the mass of an egg?"
|
Are there well developed reaction mechanisms in inorganic chemistry like those in organic chemistry? If yes, please suggest an easy to follow reference. |
Trying to identify a mystery compound, here are some of my notes, I'm trying to get a second opinion on what it might be!
**Observations**
Appears as a white powder, some chunks are formed, sticking to side of tube slightly
**Solubility**
3 drops of distilled water, all of substance dissolved
**Flame Te... |
Help identifying a compound? |
Trying to identify a mystery compound, here are some of my notes, I'm trying to get a second opinion on what it might be!
**Observations**
Appears as a white powder, some chunks are formed, sticking to side of tube slightly
**Solubility**
3 drops of distilled water, all of substance dissolved
**Flame Te... |
![enter image description here][1]
I saw this graphic in *Organic Chemistry* by Klein (2nd edition too!) and this has to be wrong, correct?
The mirror images should have the double bond on the far side of the ring in both images, right? I am sure, unless my visualization skills have totally failed me.
![en... |
I have a problem to visualize the following assignment:
What is the minimum distance between $\ce{Rb^+}$ and $\ce{I^-}$ ions if radius of $\ce{Rb^+}$ is ${1.49\cdot10^{-10}}~\mathrm{m}$ and radius of $\ce{I^-}$ is ${2.17\cdot10^{-10}}~\mathrm{m}$ if they are arranged in centered cube? |
What is the minimum distance of Rubidium and Iod ions in a centered cube? |
![enter image description here][1]
This picture shows one of the step of heme synthesis. In this step, two propanoate groups of Coproporhyrinogen III are decarboxylated to from protoporphyrinogen IX. The enzyme used is oxidase. Oxidase enzymes catalyze the removal of hydrogen (addition of oxygen) in the presence of ... |
![enter image description here][1]
This picture shows one of the step of heme synthesis. In this step, two propanoate groups of Coproporhyrinogen III are decarboxylated to from protoporphyrinogen IX. The enzyme used is oxidase. Oxidase enzymes catalyze the removal of hydrogen in the presence of oxygen to from water ... |
> So, will a water molecule form in this step. 2H+ will come from the two carboxylic groups and oxygen will combine with it to form water. Will water molecule form in this way?
No.
Firstly, note that there are 4 more hydrogen atoms in the reactant than in the product (one from each carboxylic acid group and one... |
Following up [on a somewhat too broad question][1] about amateur chemist safety, this will be the first to address some of the issues discussed there.
I often use the [NOAA MSDS database][2] (material safety data sheet) to investigate the chemicals I'm working with (they also have a nice reactivity predictor). As an... |
Would this be proper resonance structures? I know there's a lone pair on the top carbon. Having a carboanion isn't favorable as opposed to a negative formal charge on the more electronegative carbon so I flipped a bonding pair to oxygen's valence. I then proceeded to move the pi electrons inside the ring as well. This ... |
Would this be proper resonance structures? I know there's a lone pair on the top carbon. Having a carboanion isn't favorable as opposed to a negative formal charge on the more electronegative carbon so I flipped a bonding pair to oxygen's valence. I then proceeded to move the pi electrons inside the ring as well. This ... |
Following up [on a somewhat too broad question][1] about amateur chemist safety, this will be the first to address some of the issues discussed there.
I often use the [NOAA MSDS database][2] (material safety data sheet) to investigate the chemicals I'm working with (they also have a nice reactivity predictor). As an... |
For example, say you react ethyl carbamate with methyl-LiCu would two methyl groups displace both the amide and the ester creating an isopropyl alcohol? |
Would a carbamate be attacked twice by an alkyl lithium cuprate reagent? |
For example, say you react ethyl carbamate with methyl-LiCu; would two methyl groups displace both the amide and the ester, creating an isopropyl alcohol? |
How would you name this organic compound? |
Yes, it's tetramethyl heptane, where are the 4 methyls? 2,4,4,6-tetramethylheptane. |
The title says it all. I've been researching as well but all I could come close was solid state ion selective electrodes. Could someone please help me out?
There should be two methods(or one) to measure the concentrations. |
Determine Cu+2 and SO4-2 concentration using Potentiometry? |
Time and time again textbooks and websites state how wonderful it is that the deviations of Hydration Enthalpies from a linear relationship can be accounted for by the CFSE parameter for the particular complex.
My question is what is the mechanistic explanation in terms of water and the metal ion interacting ? Why d... |
Time and time again textbooks and websites state how wonderful it is that the deviations of Hydration Enthalpies from a linear relationship can be accounted for by the CFSE parameter for the particular complex.
My question is what is the mechanistic explanation in terms of water and the metal ion interacting ? Why d... |
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