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$\ce{H2SO4}$ when added to water.
$\ce{H2SO4 + 2 H2O -> SO4^2- + 2 H3O+}$
My sir explained me these reaction as $\ce{H}$ will give $\ce{2 H^+}$ ions to the base $\ce{H2O}$.So why does it not become $\ce{H4O^+}$ ?
To try to make myself understand this , I checked my textbook.
$\ce{H2SO4 + H2O <=> H3O+ + HSO4... |
$\ce{H2SO4}$ when added to water.
$\ce{H2SO4 + 2 H2O -> SO4^2- + 2 H3O+}$
My sir explained me these reaction as $\ce{H}$ will give $\ce{2 H^+}$ ions to the base $\ce{H2O}$.So why does it not become $\ce{H4O^+}$ ?
To try to make myself understand this , I checked my textbook.
$\ce{H2SO4 + H2O <=> H3O+ + HSO4... |
Can entropy change be negative for exothermic reactions? |
I was told that the statement **"all exothermic reactions have negative free energy change"** is false.
But I learnt Gibbs free energy as the "energy stored inside a system capable of doing non-$pV$ work", so I've always thought that exothermic reactions should have a negative change in free energy, i.e. $\Delta H <... |
Are all exothermic reactions necessarily spontaneous? |
> $\ce{GaAs (s)}$ is used in solar cells deployed on satellites found in the orbit of Earth. The best way to make these materials is through a technique called "molecular beam epitaxy", in which the following spontaneous chemical reaction takes place:
> $$\ce{Ga(g) + As(g) -> GaAs(s)}$$
> Pick the statement which bes... |
I am reading Lehninger biochemistry , It is mentioned that DNA do may contain Uracil but rare , Then It is mentioned that Chargaff found that number of Adenosine bases : number of thymine bases in DNA structure =1
If Uracil do present ,this ratio will be disturbed ?
Is this true or the ratio is general and approxim... |
Is the ratio between base pairs by chargaff accurate? |
Is the correct formula for diamminechloridonitrito-n-platinum(II) $\ce{[Pt(NH3)2Cl(NO2)]}$ or $\ce{[PtCl(NH3)2(NO2)]}$?
I was taught that the sequence of symbols within the coordination entity should be written in the following order:
1. The symbol of the **central metal atom** is written first.
2. The ***liga... |
I am trying to implement the direct inversion of the iterative subspace (DIIS) algorithm in my simple HF program. After some problems it now seems to work. I can calculate the correct energies in roughly the same number of steps as in the literature.
My problem is that when generating the Fock matrix from previous F... |
It is true that sometimes uracil could be present in DNA.
Uracil is almost exclusive to RNA but in some cases deamination of cytosine can cause uracil to be present in DNA.
I believe what Chargaff proposed was very crucial in understanding the structure of DNA. It was way back in 1950 (Chargaff ratio gave the clue ... |
I am trying to implement the direct inversion of the iterative subspace (DIIS) algorithm in my simple HF program. After some problems it now seems to work. I can calculate the correct energies in roughly the same number of steps as in the literature.
My problem is that when generating the Fock matrix from previous F... |
Let's take your questions one at a time.
> 1. Are there any alternative ways to purify primary amines from a complex mixture that I am unaware of?
Your end application is LC-MS. There are plenty of papers on amine-specific derivatization methods for metabolome analysis. For example, there is one by Zhao et al. \... |
I am reading Lehninger's biochemistry textbook. It mentions that DNA may rarely contain uracil. Then it mentions that Chargaff found that the ratio of adenosine bases to thymine bases in DNA is 1.
If uracil is present, will this ratio be disturbed?
Is this the A:T ratio being 1 true, or the ratio is general a... |
I have read in a textbook (Modern Quantum Chemistry Szabo and Ostlund) that the Coulomb operator of the form
\begin{equation}
\mathcal{J}_{j}\left(\mathbf{x}_{1}\right)=\int d \mathbf{x}_{2}\left|\chi_{j}\left(\mathbf{x}_{2}\right)\right|^{2}r_{12}^{-1}
\end{equation}
describes the average local potential at $\mat... |
I’m trying to rationalise the major regioisomeric product of the following reaction of an arylchloride in the presence of sodium amide:
[![enter image description here][1]][1]
I have predicted that the para-substituted product is formed as the major product because the negative charge in the meta position in th... |
I wanted to perform an MD simulation of a protein under acidic solvent conditions. A quick literature search seems to indicate that people are more interested in the protonation of protein sidechains (which is important, of course), but seems to ignore the abundance of H+ ions (ie. H3O+) in water surrounding the protei... |
I want to perform an MD simulation of a protein under acidic solvent conditions. A quick literature search seems to indicate that people are more interested in the protonation of protein side chains (which is important, of course), but seem to ignore the abundance of $\ce{H+}$ ions (i.e. $\ce{H3O+})$ in water surroundi... |
Why there is hydrogen bonding involved in salt bridge formation between glutamic acid and lysine? |
Many aquarists keeping planted tanks add CO2 from a pressurized canister to their aquaria to promote plant growth. Methods for getting the CO2 into the water vary, but some popular methods involve [a ceramic disc to release a very fine mist of bubbles][1], or trapping the CO2 bubbles into [a bell or canister which gets... |
Will CO2 bubbles ever fully dissolve in water? |
Many aquarists keeping planted tanks add CO2 from a pressurized canister to their aquaria to promote plant growth. Methods for getting the CO2 into the water vary, but some popular methods involve [a ceramic disc to release a very fine mist of bubbles][1], or trapping the CO2 bubbles into [a bell or canister which gets... |
If I have the pressure and temperature of a substance in its triple point, as well as its pressure and temperature in the critical point, how can I determine the boiling point of the substance at 1 atm of pressure? |
>Which of the following is a chemical change?
>
> A. Hydrolysis of a dipeptide.
>
> B. Stretching of a balloon.
>
> C. Freezing of water.
>
> D. Breaking a stick.
I'm pretty sure that the answer is (A), but I'm not 100% positive.
I know that, for (C), you can freeze water, and then you can melt it back... |
I have learnt that the absolute configuration of a chiral centre can be labelled as (*R*) or (*S*) according to the Cahn–Ingold–Prelog rules, when the hydrogen (or other lowest priority group) is **facing backwards, i.e. going into into the page,** and the remaining groups decrease in priority clockwise or anticlockwis... |
Many aquarists keeping planted tanks add $\ce{CO2}$ from a pressurized canister to their aquaria to promote plant growth. Methods for getting the $\ce{CO2}$ into the water vary, but some popular methods involve [a ceramic disc to release a very fine mist of bubbles][1], or trapping the CO2 bubbles into [a bell or canis... |
Many aquarists keeping planted tanks add $\ce{CO2}$ from a pressurized canister to their aquaria to promote plant growth. Methods for getting the $\ce{CO2}$ into the water vary, but some popular methods involve [a ceramic disc to release a very fine mist of bubbles][1], or trapping the CO2 bubbles into [a bell or canis... |
Please read "The Aqueous Proton Is Hydrated by More Than One Water Molecule: Is the Hydronium Ion a Useful Conceit? by Todd P. Silverstein in the Journal of Chemical Education. J. Chem. Educ. 2014, 91, 4, 608–610. It is freely available from Google Scholar.
The latest thinking, past 2006, is that $\ce{H3O+}$ does no... |
My textbook says that NH3 has more dipole moment than NF3 despite F being more electronegative than H, because the dipole moment due to the lone pair on N points in the same direction as the ones due to the H atoms, but not the F atoms. But this is the only time it talks about a dipole moment being caused by a lone pai... |
When do lone pairs affect dipole moments? |
Many aquarists keeping freshwater planted tanks [add $\ce{CO2}$ from a pressurized canister to their aquaria](https://www.aquariumgardens.co.uk/co2-set-up-guide-34-w.asp) to promote plant growth. Injection is at a slow rate to get dissolved $\ce{CO2}$ in the neighborhood of 30 ppm. Methods vary, but [a ceramic discs to... |
I have my gen chem final tomorrow and I can't figure this out. In some calorimetry problems, in which a substance is dissolved in water and we want the heat of the reaction, the mass of the dissolved substance is included in the mass plugged into mcat but other times it isn't. When should I include the mass of the subs... |
To improve your CO2 intake and not lower dissolved oxygen levels, an apparent solution is to make the water in your fish tank more alkaline and also consider increasing the surface turbulence.
The logic is that there is an equilibrium based dissociation of CO2 in water creating Carbonic acid. However, in the presenc... |
If one consumes CO, then CO binds with Heme Protein forming a Fe-CO bond. My question is if there will be any **pH dependency on IR Stretching Frequency, i.e. ν(CO) and ν(Fe-CO)**. And if there is, then what will be the result? |
Here's how it looks [like][1], I suspect that it is, though the double lines aren't rings.
My guess: a TC blow-out pipette?
[1]: https://ibb.co/Vt4XXgt |
Is my pipette a blow-out pipette? |
There are multiple issues here, and the answer is: it depends.
1. How much of your substance is there relative to the solution? If the mass is, say, 1% of total and the specific heat is comparable, then your answer may be off by 1%, which is probably smaller than the systematic measurement error from heat loss in th... |
**Background:**
Many aquarists keeping freshwater planted tanks [add $\ce{CO2}$ from a pressurized canister to their aquaria](https://www.aquariumgardens.co.uk/co2-set-up-guide-34-w.asp) to promote plant growth. Injection is at a slow rate to get dissolved $\ce{CO2}$ in the neighborhood of 30 ppm. Methods vary, but ... |
In my biochemistry laboratory class, I designed an experiment to study the effect of a His-tag on enzyme activity. First, I measured the activity of the His-tagged enzyme. Then, I cut off the His-tag (using enterokinase) and measured the activity again.
After data analysis, I was able to calculate the $K_\mathrm{M}$... |
I suspect that it is, though the double lines aren't rings. My guess: a TC blow-out pipette?
[![a pipette][1]][1]
[1]: https://i.stack.imgur.com/zd29c.jpg |
I suspect that it is, though the double lines aren't rings. My guess: a TC blow-out pipette? How am I supposed to know? I also have another one with a single dark band on the top.
[![a pipette][1]][1]
[1]: https://i.stack.imgur.com/zd29c.jpg |
I have actually, to my surprise and that of others, successfully dissolved the filament from an incandescent oven bulb, which is composed of, [per a reference](https://en.wikipedia.org/wiki/Incandescent_light_bulb), to quote:
>Incandescent light bulbs consist of an air-tight glass enclosure (the envelope, or bulb) ... |
I have actually, to my surprise and that of others, successfully dissolved the filament from an incandescent oven bulb ( [EDIT] [see before and after pictures here](https://www.sciencemadness.org/whisper/viewthread.php?tid=153380#pid621265), click to expand on the final picture), which is composed of, [per a reference]... |
**Background:**
Many aquarists keeping freshwater planted tanks [add $\ce{CO2}$ from a pressurized canister to their aquaria](https://www.aquariumgardens.co.uk/co2-set-up-guide-34-w.asp) to promote plant growth. Injection is at a slow rate to get dissolved $\ce{CO2}$ in the neighborhood of 30 ppm. Methods vary, but ... |
I have actually, to my surprise and that of others, successfully dissolved the filament from an incandescent oven bulb ( [EDIT] [see before and after pictures here](https://www.sciencemadness.org/whisper/viewthread.php?tid=153380#pid621265), click to expand on the final picture), which is composed of, [per a reference]... |
In some calorimetry problems, in which a substance is dissolved in water and we want the heat of the reaction, the mass of the dissolved substance is included in the mass plugged into mcat but other times it isn't. When should I include the mass of the substance?
For example, in this problem the mass of $\ce{NH4NO3}... |
When to include the mass of the dissolved substance in calorimetry problems? |
I suspect that it is, though the double lines aren't rings. My guess: a TC blow-out pipette? How am I supposed to know? I also have another one with a single dark band on the top.
[![a pipette][1]][1]
[![enter image description here][2]][2]
[1]: https://i.stack.imgur.com/zd29c.jpg
[2]: https://i.stack... |
I have actually, to my surprise and that of others, successfully dissolved the filament from an incandescent oven bulb ( [EDIT] [see before and after pictures here](https://www.sciencemadness.org/whisper/viewthread.php?tid=153380#pid621265), click to expand on the final picture), which is composed of, [per a reference]... |
I have actually, to my surprise and that of others, successfully dissolved the filament from an incandescent oven bulb ( [EDIT] [see before and after pictures here](https://www.sciencemadness.org/whisper/viewthread.php?tid=153380#pid621265), click to expand on the final picture), which is composed of, [per a reference]... |
I have actually, to my surprise and that of others, successfully dissolved the filament from an incandescent oven bulb ( [EDIT] [see before and after pictures here](https://www.sciencemadness.org/whisper/viewthread.php?tid=153380#pid621265), click to expand on the final picture), which is composed of, [per a reference]... |
I have actually, to my surprise and that of others, successfully dissolved the filament from an incandescent oven bulb ( [EDIT] [see before and after pictures here](https://www.sciencemadness.org/whisper/viewthread.php?tid=153380#pid621265), click to expand on the final picture), which is composed of, [per a reference]... |
I am trying to compare the electrical conductivity of selected ionic liquids (ILs) and aqueous electrolytes.
By ionic liquid (IL), I mean a pure IL -- no water. Electrical conductivity of ILs is measured in units of Siemens per length. For example, the following table from [Leys et al., *J. Chem. Phys.,* **2008**][... |
I have actually, to my surprise and that of others, successfully dissolved the filament from an incandescent oven bulb ( [EDIT] [see before and after pictures here](https://www.sciencemadness.org/whisper/viewthread.php?tid=153380#pid621265), click to expand on the final picture), which is composed of, [per a reference]... |
I have actually, to my surprise and that of others, successfully dissolved the filament from an incandescent oven bulb ( [EDIT] [see before and after pictures here](https://www.sciencemadness.org/whisper/viewthread.php?tid=153380#pid621265), click to expand on the final picture), which is composed of, [per a reference]... |
I have actually, to my surprise and that of others, successfully dissolved the filament from an incandescent oven bulb ( [EDIT] [see before and after pictures here](https://www.sciencemadness.org/whisper/viewthread.php?tid=153380#pid621265), click to expand on the final picture), which is composed of, [per a reference]... |
I have actually, to my surprise and that of others, successfully dissolved the filament from an incandescent oven bulb ([see before and after pictures here](https://www.sciencemadness.org/whisper/viewthread.php?tid=153380#pid621265), click to expand on the final picture), which is composed of, [per a reference](https:/... |
I have actually, to my surprise and that of others, successfully dissolved the filament from an incandescent oven bulb ([see before and after pictures here](https://www.sciencemadness.org/whisper/viewthread.php?tid=153380#pid621265), click to expand on the final picture), which is composed of, [per a reference](https:/... |
I remember my teacher saying that during E2(elimination bimolecular) reactions of alkanes, if the strong base that is used as a reagent is a bulky one, it has higher probability of giving a Hofmann(less stable) product as the major product even if there are possibilities for a Saytzeff product to form.
My question i... |
How to determine if a base is bulky? |
I remember my teacher saying that during E2 (elimination bimolecular) reactions of alkanes, if the strong base that is used as a reagent is a bulky one, it has higher probability of giving a Hofmann (less stable) product as the major product even if there are possibilities for a Saytzeff (or Zaitsev) product to form.
... |
I am a computer scientist, not a chemist, working with RDKit. I need to compute something described to me as "RR, the number of rigid single or fused ring systems in the molecule."
I know I can access the rings of a molecule with `AtomRings` and `BondRings`. However, I don't know how to select only the "rigid" ones.... |
No, it is an apple to orange comparison. Ley et al. are changing the frequencies and in the molar conductivity measurements you do not know what was the current frequency. It is usually measured at 1 kHz if I remember correctly. Similarly, S/m cannot be changed to Scm^2/mol. You can indeed calculate the molarity of pur... |
I am a non-chemist using RDKit to determine the number of "nonring, nonterminal atoms" in a molecule.
I can't find anything in the RDKit documentation that helps with "nonterminal". Can it be used for that?
I can using RDKit's `AtomRings` function to identify atoms in rings, but perhaps there is a more direct way... |
I tried to extract hydrogen for my kid's birthday, Mixed caustic soda with water and Aluminum foil(mixed in a glass bottle) There was a lot of heat and it released hydrogen(hope it was hydrogen). However, Within 2-3 hours, the balloons started losing altitude and started falling down. I supposed it was caused by losing... |
Elsewhere here, M. Farooq has given excellent answer for this analytical chemistry question. I like to explore this answer by explaining what are these lines means and some confusions arose from M. Farooq's answer.
The pipette is an important tool in many fields of science. There are few types of them:
- Volumet... |
Elsewhere here, M. Farooq has given excellent answer for this analytical chemistry question. I like to explore this answer by explaining what are these lines means and some confusions arose from M. Farooq's answer.
The pipette is an important tool in many fields of science. There are few types of them:
- Volumet... |
When we talk about energy bands, we are talking about mixing of orbitals on different atoms (AOs) with similar energies. First, assume simple models. In the solid, the structure is very regular and all atoms have AOs with identical matching energies. This makes the number of orbitals available for mixing in solids very... |
does it follow e2 mechanism?
If yes, then how would 2,3-dibromobutane undergo this reaction?
does it form both cis & trans butene or does it get an alkyne as product?
I had posted an elaborate question on this but it got rejected so i am posting it like this. |
I remember my teacher saying that during E2 (elimination bimolecular) reactions of alkanes, if the strong base that is used as a reagent is a bulky one, it has higher probability of giving a Hofmann (less stable) product as the major product even if there are possibilities for a Saytzeff (or Zaitsev) product to form.
... |
As mentioned in the comments, _why not_? A boron-boron bond will form as long as there is an increase in stability of the system. Forming a bond requires energy, but there is a lot of energy released once it gets formed. The feasibility of a bond depends which energy is greater.
One example of where a boron-boron bo... |
What is bound energy of H-O : wikipedia disagree with himself ?
On wikipedia english :
https://en.wikipedia.org/wiki/Chemical_bond
467 kJ/mol
On wikipedia french :
https://fr.wikipedia.org/wiki/Liaison_chimique
366 kJ/mol
What is the good information ?
Could somebody fix the wrong information ? |
What is bond energy of H-O : wikipedia disagree with himself ?
On wikipedia english :
https://en.wikipedia.org/wiki/Chemical_bond
467 kJ/mol
On wikipedia french :
https://fr.wikipedia.org/wiki/Liaison_chimique
366 kJ/mol
What is the good information ?
Could somebody fix the wrong information ? |
What is the bond energy of H-O? Wikipedia disagrees with itself:
- On [English Wikipedia](https://en.wikipedia.org/wiki/Chemical_bond):
467 kJ/mol
- On [French Wikipedia](https://fr.wikipedia.org/wiki/Liaison_chimique):
366 kJ/mol
What is the right value? |
What is the bond energy of H-O? Wikipedia disagrees with itself |
Hydrogen, having very small and fast moving molecules, diffuses faster and through smaller holes than air. Your balloons seem to be permeable for hydrogen. Try a different brand, if it helps.
Pure hydrogen just burns in a flame. If you have ever watched the film footage (1937) of the [catastrophic accident of th... |
Hydrogen, having very small and fast moving molecules, diffuses faster and through smaller holes than air. Your balloons seem to be permeable for hydrogen. Try a different brand, if it helps. But as others have mentioned, rubber is not the best material to keep hydrogen.
Pure hydrogen just burns in a flame. If you... |
Hydrogen, having very small and fast moving molecules, diffuses faster and through smaller holes than air. Your balloons seem to be permeable for hydrogen. Try a different brand, if it helps. But as others have mentioned, rubber is not the best material to keep hydrogen. Better is a metallised plastic.
Pure hydroge... |
does it follow **E2 mechanism**?
If yes, then how would **2,3-dibromobutane** undergo this reaction?
does it form both **cis** & **trans** butene or does it get an **alkyne** as product?
|
Is it an E2 reaction?
If yes, then how would 2,3-dibromobutane undergo this reaction?
Does it form both cis and trans butene or is the product butyne?
|
The *meso*-form of tartaric acid is optically inactive due to the plane of symmetry. But how are these forms able to show optical activity when the σ-bonds can freely rotate, which can change the configuration of the atoms?
[![enter image description here][1]][1]
[1]: https://i.stack.imgur.com/vZqfC.png |
If Zinc dust is the reagent then is it an E2 reaction?
If yes, then how would 2,3-dibromobutane undergo this reaction?
Does it form both cis and trans butene or is the product butyne?
|
Which mechanism will the following reaction follow?
[![enter image description here][1]][1]
Will it follow E2 mechanism?
If yes, then how would 2,3-dibromobutane undergo this reaction?
Does it form both cis and trans butene or is the product butyne?
[1]: https://i.stack.imgur.com/DTbpw.png |
Which mechanism will the following reaction follow?
[![enter image description here][1]][1]
Will it follow E2 mechanism?
If yes, then how would 2,3-dibromobutane undergo this reaction?
Does it form both cis and trans butene or is the product butyne?
[Here is a link to a website that has mentioned it is E... |
Is it possible to heat up water using chemicals? (Meaning no outside source of heat like electricity, or gas) |
I am confused regarding how the Gibbs Phase Rule works for pure substances in liquid-vapor mixtures. From the phase rule, there should only be one degree of freedom necessary for a two phase mixture with a pure substance. For example, if we pick a temperature for two phases to exist, there will only be one pressure tha... |
Are molecules robust to manipulations? |
I'm very sorry if this is a very simple question but it has been bugging me for a while Google searches for both 2-methyl propyl and 2-methyl propane give me the same structure .
My Intuition says propyl is the write one since it looses a hydrogen ,is there a very terrible flaw in my reasoning ? |
Is 2-methyl propyl and 2-methyl propane the same? |
Can the trend of spectrochemical series vary/fluctuate according to the central metal atom (CMA) that is being used?
For example, for the CMA $\ce{Ni^2+}$ the ligand $\ce{H2O}$ will have more CFSE than $\ce{NH3}$ because $\ce{NH3}$ acts as a weak field ligand (WFL) for $\ce{M^2+},$ even worse then $\ce{H2O},$ though... |
Does spectrochemical series trend depend on the metal center? |
The IUPAC name of $\ce{(CH3)3C-CH2-CHI-CH3}$ should be **4-iodo-2,2-dimethylpentane** as we consider iodine as a substituent, and we should start numbering from that carbon which is closest to the carbon with maximum number of substituents.
However, [PubChem](https://pubchem.ncbi.nlm.nih.gov/compound/2-Iodo-4_4-dime... |
I'm confused with how the Gibbs Phase Rule works for pure substances in liquid-vapor mixtures. According to the phase rule, there should only be one degree of freedom for a two-phase mixture with a pure substance. For example, if we pick a temperature for two phases to exist, there will only be one pressure that satisf... |
Mixing sodium bicarbonate with vinegar (and sometimes adding dishwasher detergent) is quite a common tip on the internet. But I have never understood the reason.
I saw there was a question about using sodium bicarbonate and vinegar here to unclog drains, where the answer referred to the production of CO2 being able ... |
Mixing sodium bicarbonate with vinegar (and sometimes adding dishwasher detergent) is quite a common tip on the internet. But I have never understood the reason.
I saw there was a question about using sodium bicarbonate and vinegar here to unclog drains, where the answer referred to the production of $\ce{CO2}$ bein... |
Although the general trend $\mathrm{s} < \mathrm{p} < \mathrm{sp}^n$ makes sense, these magic numbers $1.73$, $1.93$, $1.99$, and $2.00$ seem to have just been pulled out of a hat. If these are really "approximate strengths of bonds", a good book would justify these by showing *which* bonds they use to come up with the... |
Although the general trend $\mathrm{s} < \mathrm{p} < \mathrm{sp}^n$ makes sense, these magic numbers $1.73$, $1.93$, $1.99$, and $2.00$ seem to have just been pulled out of a hat. If these are really "approximate strengths of bonds", a good book would justify these by showing *which* bonds they use to come up with the... |
I recently conducted a simple experiment for school involving the electrolysis of water wherein I changed the concentrations of an ionic compound to determine its effect on the rate at which the products of the lysis of water are formed. I used graphite rods for the electrodes, these shed quite heavily. I noted this d... |
is it possible for graphite which has shed off metal rods during water electrolysis to bond with the hydrogen being produced to form hydrocarbons? |
I recently participated in an experiment where I need to calculated the reaction orders and the reaction constant of the reaction:
8 Na2S2O3(aq) + 16 HCℓ(aq) --> S8(s) + 8 SO2(g) + 16 NaCℓ(aq) + 8 H2O(ℓ)
by measuring time until the solution becomes too turbid for light to travel through the fluid. Calculating t... |
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