# All Questions

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### Do you have a Drug Test in the Future?

Research Chemical and Natural remedies You can trust our expertly formulated manufactured chemicals, we ensure the highest level of quality, safety and effectiveness. Our customers worldwide have ...
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### How do I calculate the molar mass of an unknown gas?

A piston is placed in a closed tube. To the left, there is Hydrogen Gas at 400K and 4 atm. To the right, there is an unknown gas at 200K and 2 atm. At equilibrium, the piston is at 1/3 of the length ...
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### In a reaction if the equilibrium constant K was infinity, could you produce an infinite number of products at equilibrium?

It's impossible to produce an infinite amount products if the k constant was infinity? no right?
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### H NMR of a molecule, help with multiplicity.

I have a the proton NMR of this molecule: There are 6 individual hydrogens and none of them are equivalent. In the spectrum I have been given there are only four peaks. I have been able to assign ...
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### What is the mechanism for demercuration?

The following image is from 'Organic Chemistry Second Edition' by Clayden, Greeves, and Warren. The final step is the demurcuration, but I'm unable to find a definitive mechanism. The wikipedia ...
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### Why do glucose, galactose and mannose differ in solubility in water?

I don't understand why they would be so different, when the only structural difference is the orientation of hydroxyl groups.
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### Rate Expression for Reactions Involving 2° Benzylic Alkyl Halides

My teacher took off marks because he said the reaction was SN1. Before I go confront him, please tell me if my reasoning is correct. So, basically, I thought: we have two possibilities: 1. SN1: a ...
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### What is the better nucleophile, Cl- or NH3? [on hold]

How do you decide? I can't seem to think of any method rather than checking experimental values.
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### NH2- and Primary Alkyl Halides: Sn2 vs E2

When we mix 1-bromopropane and NaNH2, what happens? Which reactions wins out to make the major product? My textbook says that primary alkyl halides give mainly Sn2 products unless the base is ...
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### Question about finding molar heat of solution

I have a solid dissolved in water, both the same temp, and when it's put in the temperature drops. I have the heat capacity it of the solution, and need to the molar heat of the solution of the solid ...
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### heat released from combustion of ethane

What will be the heat released when 4.42g of ethane is combusted at 298 K and 1 atm pressure?
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### Why does tomato soup “explode” when boiled? [duplicate]

When you boil tomato soup it very easily "explodes" when reaching the boiling point. Why is that? A related question has been answered here before: Why do some solutions eventually stop boiling and ...
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### What is the difference between absolute and relative configuration in stereochemistry?

I am unclear as to what the difference is - It doesn't seem to explain it well anywhere. Can you help me understand the difference between absolute and relative configuration?
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### Interpretation of TD-DFT results

For the first time I'm doing TD-DFT calculations (wB97XD functional) in Gaussian 09 for an open-shell system and the results look like the hell of a mess for me. The molecule is rather big, so I ...
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### Abstraction of a proton in cycloheptatriene

So, whenever there is abstraction of H+ by an acid-base reaction, I see that the proton on the sp3-hybridized carbon is taken. Why is this if you take into account that vinylic hydrogens are more ...
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### Grignards and diatomic halogens

Can Grignards react with diatomic halogens as to perform an substitution reaction? I'd imagine that the first part of making the reaction work - polarizing the halogen as to prepare to pull it apart ...
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### Finding compounds with B, Si, Ca, and Mg in differing amounts

Not sure if my question is better suited to a software related group, but here goes: Is there a software program that lets you add differing amounts of elements, minerals, etc., then tells you what ...
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### Which of the following ions is expected to have the lowest value of molar conductance in aqueous solution? [on hold]

Which of the following ion is expected to have lowest value of molar conductance in aqueous solution?? a. $\ce{Na+}$ b.$\ce{K+}$ c.$\ce{Rb+}$ d.$\ce{Cs+}$
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### Why does Nitrogen form N2 (and not N4) while but Phosphorus forms P4 (and not P2)?

$\ce{N2}$ is a gas $\ce{P4}$ is a solid $\ce{N}$ and $\ce{P}$ are in the same group in the periodic table The bond enthalpies are: $\ce{N#N}$ triple bond is $949~ \mathrm{kJ/mol}$ $\ce{P#P}$ triple ...
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### find the pH where is maximum the concentration of a amphiprotic substance

Considering a general amphiprotic substance NaHA. I know that the maximum concentration of the specie $HA^-$ is found at $pH = \dfrac{pKa1+pKa2}{2}$. Why? How i can confirm this statment? The ...
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### Why isn't organic chemistry taught in 3D? [on hold]

As the title says. What's the point of learning everything in 2D and trying to visualize and interpret stereochemistry, newman structures, isomers etc, with hundreds of hours wasted, when a 3d ...
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### Grams to volume question?

How many liters of $\ce{H2(g)}$ at STP are produced per gram of $\ce{Al(s)}$ consumed in the following reaction? $$\ce{2Al(s) + 6HCl(aq) → 2AlCl3(aq) + 3H2(g)}$$ Express your answer to four ...
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### Perovskite characterization

Does anyone know of groups working on water sorbtion testing and/or the use of inverse gas chromatography for characterizing Perovskites (as a class of materials)? Especially with regard to ...
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### What does 'preconcentration techniques' mean?

In the scope of the analysis of organic compounds in column-switching liquid chromatography, what does the following statement mean? sample preconcentration techniques with high enrichment ...
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### What would be the most suitable solvent for a single-solvent recrystallization?

The compound in question is acetanilide, and the solvents in question are: water, ethanol, and ethyl acetate I was thinking all three would be suitable since upon experimentation, acetanilide ...
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### Recrystallization and purification techniques for getting a pure sample

Could someone explain in detail as to why exactly recrystallization gives a more pure solid solid sample? As well as why is would be better 'technique' to allow for the crystal to form slowly? I was ...
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### Are bond angles constant?

I'd imagine the answer to the question posed in the title is no - bond angles are not constant. Covalent bonds are not infinitely rigid; hence IR as a spectroscopic technique. If so, how can we ...
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### How does a limiting reactant relate to the concentration of ions in solution?

Given the question A sample of 1.50 g of lead(II) nitrate is mixed with 125 mL of 0.100 M sodium sulfate solution. What is the limiting reactant in the reaction? Calculate the concentrations of ...
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### Obtaining the partial pressure of an unknown amount of a given gas [on hold]

Three gases (8.00 g of methane, CH4, 18.0 g of ethane, C2H6, and an unknown amount of propane, C3H8) were added to the same 10.0-L container. At 23.0 ∘C, the total pressure in the container is 5.20atm ...
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### Plotting Angular Wave Functions of Orbitals

I'm taking an introductory Chemistry class, and we are asked to plot the angular wave functions for orbitals. What exactly does the angular wave function convey or represent? I'm very confused as to ...
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### What factors might affect the reaction between potassium permanganate and ethylene glycol?

Our chemistry club has, for the last few years, been showing off some reactions to prospective students. One of the most popular tricks we have is a bit of an explosive one: we mix some potassium ...
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### What is a dl pair in stereochemistry?

Is it two isomers with at least one stereogenic center each but the corresponding center on the other isomer will rotate the plane of polarized light in the opposite direction. Is this applicable to ...
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### Structures of Thiosulfate, Dithionate & Tetrathionate Ions [on hold]

I am trying to find the structures of thiosulfate, Dithionate & Tetrathionate Ions but I am not getting an exact answer. Please help.
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### Why cant unimolecular reactions be 2nd order?

Why can't unimolecular reactions be second order? For example, doubling the concentration of a single reactant would result in four times the original rate of reaction.
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### Given the mass of precipitate, how can I calculate the relative amount of the original dissolved compounds?

A simple mixture of $\ce{NaCl}$ and $\ce{NaBr}$ weighing $0.180~ \mathrm{g}$ is treated with $\ce{AgNO3}$ solution to give $0.3715~ \mathrm{g}$ of precipitate. Calculate the content of $\ce{NaCl}$ and ...
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### Which two are the least soluble [on hold]

I did the copper lab and so the following are all copper compounds. How can I determine which two are the least soluble? Cu(NO3)2 Cu(OH)2 CuO CuSO4 Any help would be greatly appreciated!
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### Mass number of isotopes of copernicium denoted with 'm'

On this website: http://en.wikipedia.org/wiki/Isotopes_of_copernicium there is a sentence "This isomer is unconfirmed" as a footnote explaining two isotopes. What do they mean by 'isomer' in this ...
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### Determine what the unknown element is

A piece of electronic equipment originally contained 1.250 g of a valuable metal. Corrosion over time has given a compound of formula $\ce{M(OH)3}$, which is isolated but not weighed. This compound is ...
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### Chemical equilibrium question

Q1.At 25 degree Celusius and 1 atm , the partial pressures in an equilibrium mixture of N2O4 and NO2 are 0.7 and 0.3 respectively. Calculate their partial pressures when they are at equilibrium at ...
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### How effective is sulfur in detecting mercury vapors

I've read that powdered elemental sulfur will react to the presence of mercury vapor in the air creating red mercury sulfide, and that an open container of sulfur can be used as a means to verify ...
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### Finding initial pressure in a chemical equilibrium

Consider the equilibrium below. If $K = 4$ and initial pressures of $\ce{CO}$ and $\ce{H2O}$ are equal, giving a total pressure of $1.5~\mathrm{bar}$ at equilibrium. What was the initial pressure of ...
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### Which has the higher chemical shift E/Z alkene?

If you have a simple alkene for example 1-methyl-But-2-ene then you will have two methyl groups on one side of the double bond, which one of these will have the highest. Will the one on the same side ...
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### XRD-Shorter distance between planes than actual radius of atoms/or cell parameter

I'm solving problems related to X-ray diffraction, and I get these results which apparently are correct. My question may be dumb, but I just can't see how the interplanar distance might be shorter ...
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### Will lye damage vinyl pool liners?

I have a nutty neighbor that said someone told them to put liquid lye into their above ground pool. I said it would eat away the lining, their answer was to only use a little bit.
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### Assigning Carbon NMR

I have a molecule and i need to assign the carbon NMR to each of the carbons My molecule is The peaks i have for the carbon NMR are shown below. I have also used the DEPT to work out if its a CH3, ...
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### D/L Configuration

Why are D and L-glucose enantiomers???! I thought D/L refers to the "configuration" of the last chiral carbon on the open chain Fischer projection. In the D form, the higher priority group is on the ...
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### Are all anomers diastereomers?

I am told that all anomers are diastereomers. I think this is BS. If there is a carbohydrate with only one chiral center, then changing the configuration of the anomeric carbon gives us enantiomers. ...
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### Carbon-Sulfur Bond Lengths; Resonance Effects (Or Lack Thereof)

Why is the C-S bond in $\ce{CH_2SH^-}$ longer than in $\ce{CH_3SH}$? Wouldn't there be resonance in the former, forcing the C-S bond to contract? ...
How does $\ce{C6H6}$ dissociate in water? I started to read how inorganic acid dissociates in water.And stood against the above question.