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I only have basic chemistry knowledge (highschool and a bit of exposure to first year undergrad material).
I need some help figuring out what theory and techniques to study so I can work out the following problem:
If I mix sodium fluoride, calcium carbonate powder, and water, under what conditions (if any) would I ... |
In a classical reaction, phenolphthalein is synthetised from phthalic anhydride and phenol with acid catalyst. When one uses substituted phenols, one obtains similar compounds (e. g. cresolphthalein, thymohlphthalein).
However, some acid-base indicators contain a sulfo- group instead of a carboxy- group of phthalein... |
How is bromothymol blue synthetised? |
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/FJA5d.jpg
According to Dr James Keeler of Cambridge University, the angle theta can be <i>any</i> angle, but I struggle to see how this is true. There are only a certain number of <i>I</i> values that nuclei take and as illustrated in the ... |
I did a simple calculation on dinitrogen with Gamess and I wanted to reproduce the mulliken population analysis for atomic orbital
A molecular orbital is a linear combinaison of atomic orbital and if I understand correctly the mulliken analysis use coefficients to calculate population (overlap or atomic)
So in th... |
Mulliken population analysis by hand with Gamess output? |
In a classical reaction, phenolphthalein is synthetised from phthalic anhydride and phenol with acid catalyst. When one uses substituted phenols, one obtains similar compounds (e. g. cresolphthalein, thymohlphthalein).
However, some acid-base indicators contain a sulfo- group instead of a carboxy- group of phthalein... |
I have come across quite a few drugs that are of the form $\ce{HA + NaA}$, where $\ce{A}$ is your target organic compound. A few examples of this are:
* **Carmicide** which is a mixture of Sodium Citrate and Citric Acid
* **Fucidin** which is a mixture of Sodium Fusidate and Fusidic Acid
**What advantages are th... |
Why are drugs mixed with their sodium salts? |
>There is a range of elimination reactions with E1cb at one end, E1 at the other end and E2 in between. It is not uncommon for these different reaction pathways to compete with one another. For example, in some elimination reactions, the E1 and E2 pathways can operate in competition with one another. Activation energy ... |
o-Sulfobenzoic Anhydride is prepared by cyclisation of ammonium *o*-sulfobenzoate (itself prepared by cHCl hydrolysis of saccharin) with thionyl chloride in benzene. The Organic Syntheses procedure is here: [Org Syn][1]
[![enter image description here][2]][2]
[1]: http://www.orgsyn.org/demo.aspx?prep=CV1P0495... |
Bonded or not, when two atoms or ions come closer than the bond distance or the van der Waals distance, the energy increases drastically. What is the underlying cause of that repulsion?
1. The repulsion of the negatively-charged inner-shell electrons
2. The repulsion of the positively-charged nuclei (or the effec... |
I am studying chemistry, and I am learning about chromatography.
But I am confused about how chromatography is used to ‘separate and purify’ substances.
I have learnt about chromatography paper, which is used to check if a substance if pure or not. Spots of the substances to be tested are place on the chromatogr... |
Can separated and purified substances be obtained from a chromatogram? |
I'm going to use aluminium in my example, but this is applicable to _all_ metals.
Aluminium has delocalised electrons. It has aluminium cation -electron attraction. It's easier to visualize the atomic structure of aluminium in solid form.
But if it's in the gas phase, will delocalised electrons return to the ato... |
I did a simple calculation on dinitrogen with GAMESS and I wanted to reproduce the Mulliken population analysis for atomic orbitals.
A molecular orbital is a linear combination of atomic orbitals and if I understand correctly the Mulliken analysis uses coefficients to calculate population (overlap or atomic).
In ... |
How to perform Mulliken population analysis by hand with GAMESS output? |
[Wikipedia][1] gives this as **the levelling effect of water**
> Any acid that is stronger than H3O+ reacts with H2O to form H3O+.
> Therefore, no acid stronger than H3O+ exists in H2O. For example,
> aqueous perchloric acid (HClO4), aqueous hydrochloric acid (HCl) and
> aqueous nitric acid (HNO3) are all complet... |
>Consider the compound $\ce{Alkyl-(4 oxocyclopent-2-ene)carboxylate (A)}$.
Now consider the operations:
>$\ce{1. (A) + (i)BH3/THF (ii) H+}$
>$\ce{2. (A) + H2/Pt}$
>$\ce{3. (A) + H2/Pd-C}$
>###Products
> In $1.$ ester group reduced to alcohol.
>In $2.$ double bond reduced to single bond, and
> In $3.$... |
>Consider the compound $\ce{Alkyl-(4 oxocyclopent-2-ene)carboxylate (A)}$.
Now consider the operations:
>$\ce{1. (A) + (i)BH3/THF (ii) H+}$
>$\ce{2. (A) + H2/Pt}$
>$\ce{3. (A) + H2/Pd-C}$
>###Products
> In $1.$ ester group reduced to alcohol.
>In $2.$ double bond reduced to single bond, and
> In $3.$... |
[Wikipedia][1] gives this as **the levelling effect of water**
> Any acid that is stronger than $\ce{H3O+}$ reacts with $\ce{H2O}$ to form $\ce{H3O+}$. Therefore, no acid stronger than $\ce{H3O+}$ exists in $\ce{H2O}$. For example, aqueous perchloric acid ($\ce{HClO4}$), aqueous hydrochloric acid ($\ce{HCl}$) and aq... |
>Consider the compound $\ce{Alkyl-(4 oxocyclopent-2-ene)carboxylate (A)}$.
Now consider the operations:
>$\ce{1. (A) + (i)BH3/THF (ii) H+}$
>$\ce{2. (A) + H2/Pt}$
>$\ce{3. (A) + H2/Pd-C}$
>###Products
> In $1.$ ester group reduced to an alcohol.
>In $2.$ double bond reduced to a single bond, and
> ... |
What repulsion keeps non-hydrogen atoms at a distance: between inner shells or between nuclei? |
Bonded or not, when two atoms or ions come closer than the bond distance or the van der Waals distance, the energy increases drastically. What is the underlying cause of that repulsion?
1. The repulsion of the negatively-charged inner-shell electrons
2. The repulsion of the positively-charged nuclei (or the effec... |
[Wikipedia][1] gives this as **the levelling effect of water**
> Any acid that is stronger than $\ce{H3O+}$ reacts with $\ce{H2O}$ to form $\ce{H3O+}$. Therefore, no acid stronger than $\ce{H3O+}$ exists in $\ce{H2O}$. For example, aqueous perchloric acid ($\ce{HClO4}$), aqueous hydrochloric acid ($\ce{HCl}$) and aq... |
I did a simple calculation on hydrogen fluoride with GAMESS and I wanted to reproduce the Mulliken population analysis for atomic orbitals.
A molecular orbital is a linear combination of atomic orbitals and if I understand correctly the Mulliken analysis uses coefficients to calculate population (overlap or atomic).... |
[Wikipedia][1] gives this as **the levelling effect of water**
> Any acid that is stronger than $\ce{H3O+}$ reacts with $\ce{H2O}$ to form $\ce{H3O+}$. Therefore, no acid stronger than $\ce{H3O+}$ exists in $\ce{H2O}$. For example, aqueous perchloric acid ($\ce{HClO4}$), aqueous hydrochloric acid ($\ce{HCl}$) and aq... |
The order of second ionisation energy of these three elements is given as Zn > Cd < Hg.
Why is there an anomaly? |
The second Ionisation energy of the Zn, Cd, and Hg follows the order? |
It is observed that the order of second ionisation energy of these three elements is Zn > Cd < Hg.
Why is there an anomaly in the observation? |
It seems intuitive that concentrated solutions would react faster, but, when I stopped and thought about it, I got confused. Wouldn't concentrated acids and bases be in contact with less water than their more diluted counterparts, therefore being less dissociated and having less ions (H+ or OH-) available for reactions... |
How and why do concentrated solutions react faster? |
I was studying types of nuclear decay, and I came across the concept of "half-life". And I started wondering why does nuclear matter decay in half-lives? In other words, why does the rate of nuclear decay decrease as a function of time?
Is it because as more atoms decay, the surface area of the radioactive matter de... |
Why does radioactive matter decay in series of half-lives? |
[![enter image description here][1]][1]
This shows the mean bond energy for X-F, where X is a halogen. I have several questions.
1. Why is the X-F bond in $\ce{XF}$ stronger than in $\ce{XF3}$ or $\ce{XF5}$? I think it is because the $\ce{XF}$ bond has bond order 1, but $\ce{XF3}$ and $\ce{XF4}$ both have 3c-4e ... |
I have come across quite a few drugs that are of the form $\ce{HA + NaA}$, where $\ce{A}$ is your target organic compound. A few examples of this are:
* **Carmicide** which is a mixture of Sodium Citrate and Citric Acid
* **Fucidin** which is a mixture of Sodium Fusidate and Fusidic Acid
**What advantages are th... |
If I mix sodium fluoride, calcium carbonate powder, and water, under what conditions (if any) would there be an equilibrium?
i.e. Assume we start out with fully dissociated $\ce{Na + F (aq)}$, because it's fairly soluble. But when I add the $\ce{CaCO3}$, it's only slightly soluble, so assume an excess of solid $\c... |
[![The mean bond energy for X-F][1]][1]
This shows the mean bond energy for $\ce{X-F}$, where $\ce{X}$ is a halogen. I have several questions:
1. Why is the $\ce{X-F}$ bond in $\ce{XF}$ stronger than that in $\ce{XF3}$ or $\ce{XF5}$? I think it is because the $\ce{XF}$ bond has bond order 1, but $\ce{XF3}$ and $... |
Why the assumption that molecules collide with elasticity was postulated in the kinetic theory of gases while they can collide obliquely and would therefore result in change of velocity as the vector components would cancel or add up the velocities of molecules, resulting in change of velocities of molecules and energy... |
Let's say you have some ions in solution, for example Na<sup>+</sup>(aq) and OH<sup>-</sup>(aq), and some partially dissolved solid, MgCO<sub>3</sub>(s), Mg<sup>+2</sup>(aq) and CO<sub>3</sub><sup>-2</sup>(aq), which precipitates Mg(OH)<sub>2</sub>(s) until equilibrium.
So you have two solubility equilibriums intera... |
Is there a name, or any specific jargon for a precipitation equilibrium involving a solid reactant? |
I glued a sheet of paper to a cardboard package using superglue (labelled with ethyl 2-cyanoacrylate).
To my surprise the paper became very warm.
What kind of reaction is it? |
The assumption that molecules collide with elasticity was postulated in the kinetic theory of gases.
So my question is molecules should have higher tendency to collide obliquely and would therefore result in change of velocity (as the vector components would cancel or add up the velocities of molecules, resulting in c... |
Is aluminium foil pure aluminium? Or does it have other elements in the e.g: tin (Sn) or lead (Pb)? Because when I try to oxidize it through the process of submerging it in water, it doesn't look like it wants to oxidize to aluminium oxide (AlO+). I did this exact same thing with pure aluminium and it oxidized within m... |
Is aluminium foil pure aluminium? |
From *Chemistry of the Elements* by Greenwood and Earnshaw \[1, p. 833\]:
> [![The mean bond energy for X-F][1]][1]
> **Figure 17.9** Mean bond energies of halogen fluorides.
This shows the mean bond energy for $\ce{X-F}$, where $\ce{X}$ is a halogen. I have several questions:
1. Why is the $\ce{X-F}$ bond... |
I'm not a chemist but I remember that the standard HF/nitric silicon etch used in micro-fabrication supposedly worked in two steps; the HF would dissolve the thin SiO2 oxide layer on the silicon surface, exposing silicon atoms, and the nitric acid would then re-oxidize the bare silicon, allowing the HF to then dissolve... |
Understanding sodium hydroxide drain cleaner's exothermic dissolution of aluminum; does the aluminum need to be oxidized before it dissolves? |
How can be explained six bond of carbon in such a compound as [Au6C(PPh3)6]2+ ? I understand how carbon with 5 bonds can be formed ( CH5+ for instance), but it doesn't have enough electrons to form six ones. I'm sorry for being stupid, but hope someone can clear up this. |
If I mix sodium fluoride, calcium carbonate powder, and water, under what conditions (if any) would there be an equilibrium?
I.e. assume we start out with fully dissociated $\ce{Na+(aq) + F-(aq)}$, because it's fairly soluble. But when I add the $\ce{CaCO3}$, it's only slightly soluble, so assume an excess of solid ... |
According to Fajan's rule,greater charge in an ionic compound results in more covalent character but why is it that sodium oxide is more covalent than magnesium oxide?Google says boiling point of magnesium oxide is more than sodium oxide. |
How can be explained six bond of carbon in such a compound as $\ce{[Au6C(PPh3)6]^2+}?$ I understand how carbon with five bonds can be formed $(\ce{CH5+},$ for instance), but it doesn't have enough electrons to form six ones. Can someone clear this up? |
According to Fajans' rules, greater charge in an ionic compound results in more covalent character. But why is it that sodium oxide is more covalent than magnesium oxide? Google says boiling point of magnesium oxide is more than sodium oxide. |
**TL; DR**: coordination number of carbon atom in methyllithium tetramer is indeed 7, arising from 6 intramolecular interactions, as you suggested, and an extra bond with the lithium atom of the next tetramer.
----------
The key point is that you need to look *beyond* the tetramer. I'm sorry to inform you that th... |
How much electron hybridization and bonding occurs in liquid helium? |
something strange.
i made an electrochemistry experiment in which i have measured the potential of cell:
Ag, AgCl | (1M)KCl ║ [Fe(CN)6] 3-, [Fe(CN)6] 4- | Pt
with different concentrations of Fe+2/Fe+3 .
from the results i have found the faraday constant:
96181 Coulon /mol
very close to the published value (99... |
something strange.
i made an electrochemistry experiment in which i have measured the potential of cell:
Ag, AgCl | (1M)KCl ║ [Fe(CN)6] 3-, [Fe(CN)6] 4- | Pt
with different concentrations of Fe+2/Fe+3 .
from the results i have found the faraday constant:
96181 Coulon /mol
very close to the published value (99... |
I'm looking for some suitable solvent for ether cleavage of guaiacol using aluminium triiodide with DMSO. Original paper calls for using hot acetonitrile as a solvent, but I wonder what might be the alternatives. Ideal would be some solvent with only mild toxicity.
What hydrocarbon solvents are suitable replacement f... |
I'm currently studying the temperature dependence of the following cell: $\ce{Cu_{(s)} + 2Ag^{+}_{(aq)} <=> 2Ag_{(s)} + Cu^{2+}_{(aq)}}$ ($E^⦵$ = +0.46 V)
Experimentally, I recorded the initial temperature of the cell at 273 K, before increasing the temperature of the cell and recording its potential each time. This... |
I'm currently studying the temperature dependence of the following cell: $\ce{Cu_{(s)} + 2Ag^{+}_{(aq)} <=> 2Ag_{(s)} + Cu^{2+}_{(aq)}}$ ($E^⦵$ = +0.46 V)
Experimentally, I recorded the initial temperature of the cell at 273 K, before increasing the temperature of the cell and recording its potential each time. This... |
I’m quite interested in chemistry, but reading the textbooks are a bit challenging. Are there any good chemistry books for the general reader that go a bit beyond the basics? |
I'm looking for some suitable solvent for ether cleavage of Guaiacol (o-Methoxyphenol) using aluminium triiodide ($\ce{AlI3}$) with $\ce{DMSO}$. The original paper calls for using hot acetonitrile as a solvent, but I wonder what might be the alternatives. The ideal solvent would be some solvent with only mild toxicity.... |
I'm currently studying the temperature dependence of the following cell: $\ce{Cu_{(s)} + 2Ag^{+}_{(aq)} <=> 2Ag_{(s)} + Cu^{2+}_{(aq)}}$ ($E^⦵$ = +0.46 V)
Experimentally, I recorded the initial temperature of the cell at 273 K, before increasing the temperature of the cell and recording its potential each time. This... |
I'm currently studying the temperature dependence of the following cell: $\ce{Cu_{(s)} + 2Ag^{+}_{(aq)} <=> 2Ag_{(s)} + Cu^{2+}_{(aq)}}$ ($E^⦵$ = +0.46 V)
Experimentally, I recorded the initial temperature of the cell at 273 K, before increasing the temperature of the cell and recording its potential each time. This... |
How can carbon form six bonds in such a compound as $\ce{[Au6C(PPh3)6]^2+}?$ I understand how carbon with five bonds can be formed $(\ce{CH5+},$ for instance), but it shouldn't have enough electrons to form six bonds. |
How is the bonding in the [Au6C(PPh3)6]2+ cluster explained? |
Which of the following reaction will have greater enthalpy and why? |
According to [Fajans' rules][1], greater charge in an ionic compound results in more covalent character. But why is it that sodium oxide is more covalent than magnesium oxide? Google says boiling point of magnesium oxide is more than sodium oxide.
[1]: https://en.wikipedia.org/wiki/Fajans'_rules |
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/FJA5d.jpg
According to Dr James Keeler of Cambridge University in one of his lectures at Queensland University, the angle theta can be <i>any</i> angle, but I struggle to see how this is true. There are only a certain number of <i>I</i> va... |
Since the real gas particles experience attraction to each other, that means the pressure must be less from what we would expect. So why do we have to add a term to correct it?
For example, in the correction for volume, we subtract a term to find the effective volume or the "real" volume. So, it follows that the "real... |
Why is the pressure correction added in the Van der Waals equation? |
> Which of the following reaction will have greater enthalpy and why?
> $\ce{C (g) + 4 H (g) -> CH4(g)}$ (reaction enthalpy = $x\ \mathrm{kJ/mol}$)
> $\ce{C (graphite) + 2H2 (g) -> CH4 (g)}$ (reaction enthalpy = $y\ \mathrm{kJ/mol}$)
I thought that since $\ce{H2}$ is in its aggregation state it would have en... |
Ionic compounds dissolved in water, as an aqueous solution, can conduct electricity.
Can they conduct electricity if they are dissolved in organic solvent? |
Can ionic compounds dissolved in organic solvent conduct electricity? |
I'm currently studying the temperature dependence of the following cell: $\ce{Cu_{(s)} + 2Ag^{+}_{(aq)} <=> 2Ag_{(s)} + Cu^{2+}_{(aq)}}$ ($E^⦵ = \pu{+0.46 V}$)
Experimentally, I recorded the initial temperature of the cell at $\pu{273 K}$, before increasing the temperature of the cell and recording its potential eac... |
Since real gas particles experience attraction to each other, that means the pressure must be less from what we would expect. So why do we have to add a term to correct it?
For example, in the correction for volume, we subtract a term to find the effective volume or the "real" volume. So, it follows that the "real" pr... |
I'm cleaning up some mould around the home and I have some substance on my window sills which I'm not quite sure if it's dirt or mould.
I have read about using Vinegar to clean up mould, but an article I was reading awhile back said you shouldn't use Vinegar on certain things as it can eat away at it or something be... |
Cleaning with Vinegar - what surfaces does it react badly with? Metal window sills ok? |
I printed an object with a 3D printer and I used a roll of light green ABS plastic filament.
I would like to use the dishwasher to clean it. The temperature would be kept below 70°C, well below the glass transition temperature of about 110°C.
The dishwasher uses standard tabs, not one of the phosphate-free tabs.
... |
Would ABS plastic degrade in a dishwasher? |
I was reading my Chemistry textbook and I noticed that it stated that for a system at equilibrium:
1. At constant temperature, reducing the volume of gaseous equilibrium mixture causes the system to shift in the direction that reduces the number of moles of gas. Increasing the volume will shift the system in the dir... |
Helium is the only element which does not freeze at atmospheric pressure, and only forms a liquid at around 4 Kelvin due to weak van der Waals forces.
I'm interested in knowing roughly how much hybridization/bonding occurs in liquid helium (for example, hybridization energy in cm$^{-1}$ or electronvolts). I would gu... |
If someone writes "NAD(P)H is oxidized by ...", does that mean they are referring to both NADH and NADPH?
If so doesn't that lead to confusion when thinking quantitatively since the reactions may proceed at different rates, NAD may be present in a different concentration than NADPH, etc?
If not, what do the pare... |
What is the meaning of parentheses in "NAD(P)H"? |
I'm not a chemist but I remember that the standard HF/nitric silicon etch used in micro-fabrication supposedly worked in two steps; the HF would dissolve the thin SiO2 oxide layer on the silicon surface, exposing silicon atoms, and the nitric acid would then re-oxidize the bare silicon, allowing the HF to then dissolve... |
Say a sample has two alkaloids, one with a molecular weight of 521.44 g/mol and one with a weight of 521.66 g/mol.
Would column chromatography be able to separate these two alkaloids?
Also, what if a sample has, say 15 different alkaloids. Will all of these separate in liquid column chromatography?
Thanks. |
Can basic column liquid chromatography separate two extremely similar alkaloids? |
$\mathrm{s}$ orbitals are spherically symmetric while $\mathrm{p}$ orbitals are not. For Boron, the electronic configuration is $\mathrm{1s^2 2s^2 2p^1}$.
In which p orbital does the most energetic orbital lie? Is it $\mathrm{p}_x$, $\mathrm{p}_y$ or $\mathrm{p}_z$? Since all the three are degenerate, how does the e... |
$\mathrm{s}$ orbitals are spherically symmetric while $\mathrm{p}$ orbitals are not. For Boron, the electronic configuration is $\mathrm{1s^2 2s^2 2p^1}$.
In which p orbital does the most energetic electron lie? Is it $\mathrm{p}_x$, $\mathrm{p}_y$ or $\mathrm{p}_z$? Since all the three are degenerate, how does the ... |
I've seen that the first ionization energy of a particular metal is always greater than its work function. Is it the case always? If so why?
For example, the first ionization energy of sodium is $5.14\mathrm {eV}$/atom.
(source: [here](http://hyperphysics.phy-astr.gsu.edu/hbase/Chemical/ionize.html))
while it... |
I read this in an old chemistry book. It says "When selenium is dropped into melted phosphorus, it dissolves rapidly, and the compound sinks through the liquid phosphorus in red streaks." My question is whether the phosphorus is red or white? |
Se+P White or red P? |
From my class text book,
the oxidation states of Vanadium ions 5+ and 4+ are shown in the compounds VO2^+
and VO^2+ respectively, whereas V3+ and V2+ are shown like this in the redox reaction (reduction half equation).
Why is this? cannot V5+ and V4+ exist indpepently as ions like V3+ and V2+ (when measuring th... |
Can the 5+ and 4+ oxidation state of Vanadium ion exist independently? |
I know nothing about chemistry, I managed not to take it in correspondence high school. I don’t know how to read or make sense of this: CuAl₆(PO₄)₄(OH)₈ • 4H₂O the chemical formula of turquoise. From looking at a children’s periodic table I figured out some of the letters like Copper and aluminum, but I don’t know what... |
To aquire the yellow colour of vanadium ion, it must be rpesent in a 5+ oxdiation state.
This can be acheived (according to my textbook) by adding dilute sulfuric acid to NH4VO3-, then followed by zinc.
VO3- (aq) + 2H+ (aq) ---> VO2^+ (aq) + H2O (l)
where VO2^+ gives the yellow colour from the V5+ present in ... |
Colour of VO3^-? |
To aquire the yellow colour of vanadium ion, it must be present in a 5+ oxdiation state.
This can be acheived (according to my textbook) by adding dilute sulfuric acid to NH4VO3-, then followed by zinc.
VO3- (aq) + 2H+ (aq) ---> VO2^+ (aq) + H2O (l)
where VO2^+ gives the yellow colour from the V5+ present in t... |
To aquire the yellow colour of vanadium ion, it must be present in a 5+ oxdiation state.
This can be acheived (according to my textbook) by adding dilute sulfuric acid to NH4VO3-, then followed by zinc.
VO3- (aq) + 2H+ (aq) ---> VO2^+ (aq) + H2O (l)
where VO2^+ gives the yellow colour from the V5+ present in t... |
When we have an exothermic reaction as well as a decrease of the entropy in the system after the reaction, why does the decrease in the entropy of the system diminishes the amount of useful work we can extract from the system?
In my opinion, if we have at the final state less accessible microstates than at the init... |
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