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The title says it all.
I had this question when helping someone with their high-school chemistry homework. What are the reasons that someone would use an (from my point of view) obfuscated notation? |
Why NH4OH? Why not NH3(aq)? |
Actually this is going to be a list of interconnected questions. Please bear with me.
![Cyclodextrin structure][1]
[1]: https://i.stack.imgur.com/wZDnA.jpg
Wikipedia article on cyclodextrin (CD) says that it is hydrophobic from inside.
(1) How is it hydrophobic when there are so many hydroxyl groups o... |
Why is Cyclodextrin cavity hydrophobic? |
At high enough pressure, atomic material no longer exists, for example under the conditions of a neutron star. Is there a different maximal pressure above which covalent bonds no longer exist? |
Regarding the last part "Do we feel heat or the temp?" - this is more physiological then chemical, but I want to share this anyway.
We feel heat flux, i.e. how fast heat is removed or supplied to our skin. Since heat flux can be both advection in the surrounding medium (e.g. air) or conduction in the skin it depends... |
Regarding the last part "Do we feel heat or the temp?" - this is more physiological then chemical, but I want to share this anyway.
We feel heat flux, i.e. how fast heat is removed or supplied to our skin. Since heat flux can be both advection in the surrounding medium (e.g. air) or conduction in the skin it depends... |
What is the name of the molecule that has the greatest number of different kinds of atoms?
For example, H2O is water has 2 different kinds of atoms which are H and O.
For example, C6H12O6 is fructose and has 3 different kinds of atoms which are C, H and O.
After warned to be a too broad question. I will rephra... |
A cylinder contains 2 kg of steam at 200kPa and 200oC. Now steam is compressed at constant pressure until its temperature rises to 250oC. What is the work done during this compression process? |
What is the compression work? |
With the twist of thumbscrew, a hand-held diamond anvil cell will exert 300 GPa (43,500,000 psi). No chemical bonding problem there. If you stack stuff - planetary and stellar cores - it gets more interesting, depending on composition and temperature. Temperature matters.
http://en.wikipedia.org/wiki/Electron_de... |
>Why is weight of 1 mole of substance equal to atomic/molecular mass in grams?
According to me, it happens because mole has been defined in such a way. It is defined as the numbers of particles in 12 g of C<sup>12</sup>. If it were 24 g, instead of 12 g, then the weight of 1 mole of substance would equal 2 times th... |
This is more of a meta-chemistry question, but, here goes...
Given the structure of a polymer, how can I search online for which polymer it is?
Specifically, I have an image like this:
![enter image description here][1]
I'd also like to know which polymer specifically this is, but also a method for figuring... |
How do I lookup a polymer by its structure? |
Let's say I want to take a random plant , and get the chemical formulas of the compounds he's made of. Is there an automated method for doing so and how costly is it(roughly) ? |
How do i detect the compounds a plant is made of, automatically? |
The changing of the colour of NO2 is because of
a change in temperature? or
heating and cooling? |
Does Nitrogen dioxide change colour if we put it in a constant temperature of e.g. 100 kelvin? |
Which more stable in aqueous solution Cr$^{3+}$ or Mn$^{3+}$? And why?
My approach: Cr$^{3+}$ should be more stable as the 3d e$^-$ will enter $t_{2g}$ orbitals. Due to CFSE of half filled $t_{2g}$ orbitals Cr$^{3+}$ should be most stable. |
One-dimensional Fabre and Bechgaard salts, TTF-TCNQ,
![enter image description here][1]
http://www.chem.tamu.edu/rgroup/dunbar/Publications/2002-147.pdf <BR>
platinum blues
DOI:10.1002/asia.200700370 <BR>
hexaphenylbenzene discotic liquid crystals <BR>
http://www.crcpress.com/product/isbn/9781439811436 <BR>... |
I need to calculate the heat of combustion per mole and per kilogram of complete combustion of, say, X.
1. I write reaction equation: X + O2 -> ... + Q
2. Find Q using Hess law
3. What is next?
Thanks for help! |
Which more stable in aqueous solution Cr$^{3+}$ or Mn$^{3+}$? And why?
My approach: Cr$^{3+}$ should be more stable as the 3d e$^-$ will enter $t_{2g}$ orbitals. Due to CFSE (Crystal Field Stabilization Energy) of half filled $t_{2g}$ orbitals Cr$^{3+}$ should be most stable. |
I need to calculate the heat of combustion per mole and per kilogram of complete combustion of, say, X.
1. I write reaction : X + O2 -> ... + Q
2. Find Q using Hess law
Now, what do I do after that? |
I need to calculate the heat of combustion per mole and per kilogram of complete combustion of, say, X.
1. I write reaction : $\ce{X + O2 -> ... + Q}$
2. Find Q using Hess law
Now, what do I do after that? |
Can you tell me the reason why oxalic acid has its 2nd -COOH group flipped?
I'm guessing its something to do with steric replusions between the -cooh group im not sure. |
Cr(III) is common as dirt and stable in solution as any number of different salts. Mn(III) is exotic, labile, and chemically reactive,
http://www.hach.com/asset-get.download.jsa?id=7639984472 <BR>
DOI: 10.1039/AN9911600285 <BR>
http://en.wikipedia.org/wiki/Manganese(III)_acetate <BR>
DOI:10.1039/C3RA42480D <BR>... |
What do hardness and softness mean?
Is it something to do with the polarisability. |
Hardness and softness are terms used to describe which aspect of acidic behaviour? |
Thermodynamics proposes, kinetics disposes. The most stable form can have a high activation energy barrier surrounding it. The medium matters. Hard Lewis bases (water) stabilize high oxidation states (Cu(II), tungstate). Soft Lewis bases (acetonitrile) stabilize low oxidation states (Cu(II); $\ce{W(CO)6}$ and http:... |
I am attempting to adapt a hydrothermal method for synthesizing PbS nanocrystals to my school that contains a mixture of cationic and anionic surfactants sodium dodecyl sulfate (.05 mmol, SDS) and cetyltrimethylammonium bromide (.05 mmol, CTAB) and ethylenediaminetetraacetic acid (.2 mmol, EDTA) as a chelating agent th... |
What is the difference between the reactivity of Lead subacetate and Lead II acetate undergoing a hydrothermal process? |
Is it due to the aldol reaction that happens? But the product of that reaction is still soluble in acetone.
Apparently if you have a solid mixture of 6-ethoxycarbonyl-3,5-diphenyl-2-cyclohexenone with NaOH and Na2CO3 impurites, and you dissolve them in acetone, after which you centrifuge, the solid impurites will s... |
Suppose we have some fermented (optionally also distilled) fruit/fruit juice. The sample therefore contains water, sugars, ethanol etc. Which analysis method is the simplest to find out whether the toxic methanol is also present? |
How to find trace methanol content in fermented fruit/distillate? |
If a ligand K[Ag(CN)<sub>2</sub>] is ionizated.. Which one is correct ionization equation?
K[Ag(CN)2] --> K<sup>+</sup> + Ag<sup>+</sup> + 2CN<sup>-</sup>
or
K[Ag(CN)2] --> K<sup>+</sup> + [Ag(CN)2]<sup>-</sup> |
If a ligand K[Ag(CN)<sub>2</sub>] is ionizated.. Which one is correct ionization equation?
$$\ce{K[Ag(CN)2] --> K+ + Ag+ + 2CN-}$$
or
$$\ce{K[Ag(CN)2] --> K+ + [Ag(CN)2]-}$$ |
If a ligand K[Ag(CN)<sub>2</sub>] is ionizated.. Which one is correct ionization equation?
$$\ce{K[Ag(CN)2] -> K+ + Ag+ + 2CN^-}$$
or
$$\ce{K[Ag(CN)2] -> K+ + [Ag(CN)2]^-}$$ |
A cylinder contains 2 kg of steam at 200 kPa and 200 $^\circ$C. Now steam is compressed at constant pressure until its temperature rises to 250 $^\circ$C. What is the work done during this compression process? |
If a ligand K[Ag(CN)<sub>2</sub>] is dissociated.. Which one is correct dissociation equation?
$$\ce{K[Ag(CN)2] -> K+ + Ag+ + 2CN^-}$$
or
$$\ce{K[Ag(CN)2] -> K+ + [Ag(CN)2]^-}$$ |
Most health-food stores carry supplements supposedly containing iodine for people with iodine deficiency. I recently bought some kelp tablets that are supposed to have iodine but as a consumer how can I be sure that there is any iodine in them at all, let alone the claimed minimum daily requirement. How do I know that ... |
Is calculus and differential equations really that useful in physical chemistry? How does knowing that helps me in physical chemistry? And how much of calculus must I know in order to do physical chemistry topics such as thermodynamics? Because I am currently a chem major and am wondering what maths courses would be re... |
If -2 is a oxidation number and 2- is the charge, then what is - by itself, is it a oxidation number or charge? As in Ag+.
Also do you see Cu+2Ag+ $\rightarrow$ Cu2+ +2Ag as a redox reaction? Because I don't see any increase or increase in the oxidation number of any element in this equation. All I see is charges |
If -2 is a oxidation number and 2- is the charge, then what is - by itself, is it a oxidation number or charge? As in $Ag^+$.
Also do you see $Cu+2Ag^+$ $\rightarrow$ $Cu^{2+} +2Ag$ as a redox reaction? Because I don't see any increase or increase in the oxidation number of any element in this equation. All I see is ... |
If -2 is a oxidation number and 2- is the charge, then what is - by itself, is it a oxidation number or charge? As in $\ce{Ag+}$.
Also do you see $\ce{Cu + 2Ag+ -> Cu^{2+} + 2Ag}$ as a redox reaction?
Because I don't see any increase or increase in the oxidation number of any element in this equation. All I see... |
Is there a general way to predict products of a chemical reaction, given only the atomic masses of masses of all elements involved? for example:
1. $\ce{CuFeS2 + O2->}$
2. $\ce{K2CrO4 + H2SO4->}$
3. $\ce{FeOCr2O3 + K2CO3 + O2->}$
4. $\ce{K2Cr2O7 + H2SO4->}$
If there's no method to do so, are we supposed ... |
In cold countries, it is a common phenomena to add salt to melt or clear snow. However, only specific salts are being commercially. So my question is that why only Sodium Chloride and CaCl2 are used for addition to snow, to melt/clear it? |
I would love to add some quantum chemical bone to the stew we are trying to cook here.
Let us assume that it is possible to have a solution of carbonate ions, like already discussed by Nicolau in the [comments][1]. Then [Rauru][2] is also right that you will have to consider several equilibria:
\begin{aligned}\ce{
... |
I just had to read some general descriptions of sodium chloride and it was always classified as odourless (e.g., by [Wikipedia](http://en.wikipedia.org/wiki/Sodium_chloride)). However, large amounts of table salts (around 1 kg) have a clearly perceptible odour to me.
Is the classification as *odourless* just an appr... |
Is sodium chloride really odourless? If yes, what do I smell? |
I have a graph of a titration of a weak polyprotic acid with a strong base.
I graphed pH versus amount of strong base added.
Now being polyprotic acids, how do I determine which equivalence point is the final one?
Also not sure how to find the initial concentration of the weak acid? I know of course the volum... |
Properties of Polyproic acids? |
I have heard that mass spectrometry is very time consuming: why is this? What is the process involved in performing a mass spectrometry experiment? What steps are the most time consuming? |
What is the process involved in performing a mass spectrometry experiment? |
I just had to read some general descriptions of sodium chloride and it was always classified as odourless (e.g., by [Wikipedia](http://en.wikipedia.org/wiki/Sodium_chloride)). However, large amounts of table salts (around 1 kg) have a clearly perceptible odour to me. By *table salt* I mean salt sold for the purpose of ... |
For example consider:
$$aA + bB \rightarrow pP + nN$$ where $a, b, p$ and $n$ are moles.
The equilibrium constant is $$ \frac{[P]^p [N]^n }{[A]^a [B]^b}$$ Where does this come from? I don't understand why anyone would multiply the concentrations of the products together and then divide it by the product of the re... |
Water molecules are described as an oxygen atom covalently (ignoring for the monent protonization/deprotonization) bonded to two hydrogen atoms with an angle of ~104° between the hydrogen atoms (like Mickey Mouse). I can understand this with multiple water molecules (the stacking would - for want of better descriptive ... |
Configuration of a water molecule? |
We have a 120 ml water sample with an unknown concentration of benzene. If the bottle size is 160 ml (with 40 ml of air) and benzene has reached equilibrium, what fraction of benzene is left in the water?
We are only given Hcc (Henry constant - Cair/Cwater) 0.225 and Log Kow (to which I believe is needed for a late... |
We are always told that to excite an electron from one state to a higher energy states, for example from the valance band to the conduction band, the energy must *equal* the energy difference between the two energy states.
The conduction band consists of many allowed energy states, separated from the valance band by... |
How strict is the "to excite electrons the energy must equal the energy state difference" fact? |
I learnt that all strong acids have a 100% degree of ionisation and that there are no degrees of strength in acids but I also read that fluoroantimonic acid is **20 quintillion** times stronger than 100% sulfuric acid !!
Can you please explain the chemistry behind this? |
Salt is very commonly added to ice even at room temperature to prevent it from melting. Can anyone explain how does it really work? |
> how do i find the set of quantum numbers for a specific electron in an element?
>
For example, calculate the set of quantum numbers for the 19th electron in chromium.
>
please explain the working methodology as well..
cheers! :) |
how to calculate quantum numbers for an electron? |
I kind of get the idea of singlet and triplet states. But why are they called singlet and triplet (what is the single and what is the triple in these cases)?
I feel that I am missing something obvious! |
Why is a singlet state called singlet and a triplet state called triplet? |
Say I promote a molecule to a triplet state via repeated electronic excitation events. Here, this is going to mean that an electron from the HOMO level, originally with a spin-UP and spin-DOWN electron, will be promoted to the LUMO level s.t. its spin is the same as the electron left-over in the HOMO level (we can the... |
How do I find the set of quantum numbers for a specific electron in an element? For example,
>Calculate the set of quantum numbers for the 19th electron in chromium.
Please explain the working methodology as well. |
What is the appropriate procedure for determining the quantum numbers of an electron? |
This question was posed a couple years ago but not answered adequately. You can view the older thread [here][1]. The cellulose membrane commonly used in high school and university labs is widely available from suppliers such as Wards, [Carolina][2], Flinn, PASCO, etc. The specifications are either available online or w... |
Why is dialysis tubing impermeable to sucrose? |
How do I find the set of quantum numbers for a specific electron in an element? For example,
>Calculate the set of quantum numbers for the 19th electron in chromium.
Please explain the working methodology as well..
cheers :) |
I learned that all strong acids have a 100% degree of ionization and that there are no degrees of strength in acids; however, I also read that fluoroantimonic acid is **20 quintillion** times stronger than 100% sulfuric acid !!
Can you please explain the chemistry behind this? |
Benedict's reagent detects reducing sugars (free aldehyde group) by reducing soluble blue Cu(II) to insoluble red Cu(I) oxide. Sucrose aquoous solution is inert unless it is pre-hydrolyzed by heating with strong acid catalyst.
That certainly is a poser. One possibility (SWAG, not fact) is regenerated crosslinked c... |
A common problem in shooting sports is precipitation of lead onto aluminum suppressor baffles. (The lead presumably comes from both lead styphnate priming compound and from the base and bearing surface of lead bullets that vaporize during propulsion.)
If the lead precipitate is allowed to build up a contiguous laye... |
How do I find the set of quantum numbers for a specific electron in an element? For example,
>Calculate the set of quantum numbers for the 19th electron in chromium.
The electronic configuration of the 19th electron is 1s2 2s2 2p6 3s2 3p6 4s1. From here on, how do I decide what would the principle quantum number... |
What does it mean for an element to be reduced?
What does it mean for an element to be oxidized?
What is an oxidizing agent?
What is a reducing agent?
How do you identify oxidizing and reducing agents? |
Unfortunately there are no (or only very hard to find) studies to the mechanism of the actual sorption of arsenic (acids) to magnetite. Most literature does describe it as a simple Ligand exchange, although I find that hard to believe. From what I have read ([1][1], [2][2], [3][3] = [3en][3en], [4][4]) I will try to co... |
Simple question.
How does household glue work? How does it attach to almost any other compound? Thanks. |
How does glue work? |
Here is the problem: How many ml of acidified $\ce{K2Cr2O7}$ solution, which includes 21.6 g of dichromate ions per Litre, are required for the oxidation of 44.4 g of $\ce{CH3CH2CH(OH)CH3}$?
Obviously 44.4 g of $\ce{CH3CH2CH(OH)CH3}$ means 0.6 moles. So from the stoichiometry of the the oxidation we find out th... |
Here is the problem: How many ml of acidified $\ce{K2Cr2O7}$ solution, which includes 21.6 g of dichromate ions per Litre, are required for the oxidation of 44.4 g of $\ce{CH3CH2CH(OH)CH3}$?
Obviously 44.4 g of $\ce{CH3CH2CH(OH)CH3}$ means 0.6 moles. So from the stoichiometry of the the oxidation we find out th... |
Please can some one give me a complete list of all the half equations for H2O2 both oxidatation and reduction, in acidic and alkaline conditions. I have looked on the internet but can't seem to find a list with all of them on? |
I want to test a process that involves N-methylimidazole and diphenyl disulfide.
I am not doing academic research, but rather testing a documented reaction for application to an industrial process, so I don't believe I need lab-grade chemicals.
When I look for those chemicals online I can only find lab suppliers ... |
Where can I buy cheap reagents? |
Please can some one give me a complete list of all the half equations for H2O2 both oxidatation and reduction, in acidic and alkaline conditions. I have looked on the internet but can't seem to find a list with all of them on? These are my first attempts: H2O2 + 2e^- -> 2OH^- (in alkaline conditions), H2O2 + 2H^+ + 2e^... |
I want to test a process that involves N-methylimidazole.
I am not doing academic research, but rather testing a documented reaction for application to an industrial process, so I don't believe I need lab-grade chemicals.
When I look for this solvent online I can only find lab suppliers (e.g., Matrix Scientific, ... |
I want to test a process that as documented in the literature uses N-methylimidazole.
I am not doing academic research, but rather testing a documented reaction for application to an industrial process, so I don't believe I need lab-grade chemicals.
When I look for this solvent online I can only find lab supplier... |
Where can I buy cheap N-methylimidazole, or what substitutes for it? |
I want to test a process that as documented in the literature uses N-methylimidazole.
I am not doing academic research, but rather testing a documented reaction for application to an industrial process, so I don't believe I need lab-grade chemicals.
When I look for this solvent online I can only find lab supplier... |
Please can some one give me a complete list of all the half equations for H2O2 both oxidatation and reduction, in acidic and alkaline conditions. I have looked on the internet but can't seem to find a list with all of them on?
These are my first attempts:
- $\ce{H2O2 + 2e^- -> 2OH^-}$ (in alkaline conditions)
... |
Why is mass proportional to the strength of a dipole-dipole attraction? meaning more mass more strength |
I am attempting to adapt a hydrothermal method for synthesizing $\ce{PbS}$ nanocrystals to my school that contains a mixture of cationic and anionic surfactants sodium dodecyl sulfate (.05 mmol, SDS) and cetyltrimethylammonium bromide (.05 mmol, CTAB) and ethylenediaminetetraacetic acid (.2 mmol, EDTA) as a chelating a... |
Which fragmentation is possible at this m/z value for <strike>pthalic</strike> *phthalic* acid diethyl ester?
I tried mac- Lafferty but it didn't solve my problem.
Any help would be appreciated. |
I have a graph of a titration of a weak polyprotic acid with a strong base.
I graphed pH versus amount of strong base added.
Now being polyprotic acids, how do I determine which equivalence point is the final one?
Also not sure how to find the initial concentration of the weak acid? I know of course the volum... |
Why is the groundstate electronic degeneracy of monoatomic O(g) 5? |
From [Proceedings of the Symposium on Oxygen Electrochemistry](http://books.google.it/books?id=cptVx_1zpawC&pg=PA198&dq=hydrogen+peroxide+electrochemistry&hl=it&sa=X&ei=k_FhU_zvMoqFtQa1oIDIDg&ved=0CEsQ6AEwAA#v=onepage&q=hydrogen%20peroxide%20electrochemistry&f=false) plus [Water Research 36 (2002) 85–94](http://www.res... |
Consider a binary azeotropic solution of two volatile components $A, B$. I wanted to try and find out the required concentrations of $A, B$ in the solution in terms of their vapour pressures. I tried using Raoult's Law to do this, but the I got an unexpected answer:
Let the vapour pressure of $A, B$ at the current t... |
From [Proceedings of the Symposium on Oxygen Electrochemistry](http://books.google.it/books?id=cptVx_1zpawC&pg=PA198&dq=hydrogen+peroxide+electrochemistry&hl=it&sa=X&ei=k_FhU_zvMoqFtQa1oIDIDg&ved=0CEsQ6AEwAA#v=onepage&q=hydrogen%20peroxide%20electrochemistry&f=false) plus [Water Research 36 (2002) 85–94](http://www.res... |
From [Proceedings of the Symposium on Oxygen Electrochemistry](http://books.google.it/books?id=cptVx_1zpawC&pg=PA198&dq=hydrogen+peroxide+electrochemistry&hl=it&sa=X&ei=k_FhU_zvMoqFtQa1oIDIDg&ved=0CEsQ6AEwAA#v=onepage&q=hydrogen%20peroxide%20electrochemistry&f=false) plus [Water Research 36 (2002) 85–94](http://www.res... |
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