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24
votes
3answers
13k views

Which is the densest gas known?

Which is the densest gas known to exist under normal "shirt sleeve" conditions: room temperature, one atmosphere, won't explode on contact with air, won't kill everyone in the building in trace ...
6
votes
1answer
21k views

Salt concentration and electrical permittivity of water

We know that the electric flux density $D$ can be related to electric field intensity $E$ as $D=\epsilon(\omega) E$ $\epsilon(\omega) = \epsilon_0 \epsilon_r(\omega) $ where $\epsilon_0$ is the ...
5
votes
2answers
5k views

How to interpret the MSDS warning?

Just a quick question; I was looking up the MSDS for o-Toluic Acid for an experiment when I came across this in the "Hazards Identification" section. ...
6
votes
1answer
698 views

Why is sugar used in low-cost homemade rockets?

I was thinking about making a "rocket candy". It's relatively inexpensive rocket based on sugar and some oxidiser, mostly $\ce{KNO3}$. The fuel is usually formed by heating the mix of both compounds ...
41
votes
3answers
7k views

Carbon atoms at the edge of a diamond

It is well known (the simplest textbook example) that a diamond has a well-defined arrangement of sp3 carbon atoms, as each atom is connected to four others in a ...
3
votes
1answer
239 views

Electron Transfer in Organic Reactions: Why Does Brown Iron Oxide Improve Burn Rate of Rocket Candy?

On wikipedia, this statement exists about rocket propellant aditives: Metal oxides have been found to increase the burn rate of sugar propellants. [...] Most often used are iron oxides. Red iron ...
4
votes
1answer
654 views

Simple experiments involving enantiomer synthesis

I want to do an experiment to investigate factors affecting the synthesis of chiral molecules. The only problem is, my institution doesn't have much money, and it seems like the chemicals required for ...
3
votes
1answer
182 views

Approach to model solvent in a lattice: e.g. H2O in NaCl

If a lattice contains a solvent, lets say $\ce{NaCl}$ and water of crystallisation, what is the condition for a solvent molecule to change it's location? From my current point of view I assume that ...
0
votes
1answer
677 views

Here are four observations of the reactions of four metals

Here are four observations of the reactions of four metals. Metal F and G react slowly with water Metal H displaces metal G from its chloride salt solution Metal E does not react with dilute acids ...
3
votes
2answers
148 views

Why does the pH of this solution rise instead of fall when exposed to the atmosphere?

I have a couple of big barrels with a $50\,\mathrm{L}$ demi-water solution of the following nutrients: $$ \begin{array}{rl} 200~\mathrm{\mu M} & \ce{NH4NO3} & +\\ 30~\mathrm{\mu M} & \ce{...
1
vote
1answer
920 views

Does the iodoform reaction form hydrogen iodide or water?

I am currently learning about the iodoform reaction, i.e. when CH3COR compounds react with iodine and sodium hydroxide to form iodoform. My course book and Chemguide both says that the reaction is as ...
4
votes
1answer
156 views

Proton affinities in machine readable format?

Short: How to get proton affinities for a large list of chemicals? A database? A programming API? Longer: I have ca. 2000 chemicals (downloaded from MCM, mostly organics that occur in the atmosphere ...
0
votes
1answer
267 views

Relative abundance of the isotopes of iridium

There are two stable isotopes of iridium, $\ce{^191Ir}$ and $\ce{^193Ir}$. If you randomly pick an iridium atom from a large collection of iridium atoms, which isotope are you more likely to select?
8
votes
3answers
36k views

ATP break down and energy release?

I have a very basic question. Energy is absorbed to break bonds. Bond-breaking is an endothermic process. Energy is released when new bonds form. Bond-making is an exothermic process. But ATP breaks ...
1
vote
0answers
57 views

What kind of salts may I add in my GPC Eluent? [closed]

What kind of salts may I add in my GPC Eluent?
11
votes
3answers
2k views

Significance of 4π in the uncertainty principle

What is the significance of the quantity 4π in the Heisenberg uncertainty principle? $Δp \times Δx = \frac{h}{4π}$ The focus of the question is to learn why the ratio of a circle's circumference to ...
5
votes
3answers
8k views

What is Chevron with Techron fuel?

I've heard the commercials for this stuff for years, but what exactly does it do? Does it do what the commercials say it does (clean out deposits in your tank)? How well? In other words, is this ...
16
votes
1answer
4k views

What is the IUPAC systematic name for methane?

The 1993 IUPAC Blue Book claims that "methane" is a semisystematic name: Semisystematic names also exist, such as "methane", "propanol", and "benzoic acid", which are so familiar that few chemists ...
8
votes
2answers
2k views

Dibromomethane bond angles

With regard to the above professor's claim, I disagree. Bent's rule, which states that atomic p-character is concentrated in orbitals directed toward more electronegative substituents, implies that ...
12
votes
4answers
9k views

Is there a catalyst that will reduce an alcohol to an alkane?

There are many reduction methods of going from an alcohol to an alkane: http://www.transtutors.com/chemistry-homework-help/hydrocarbons/reduction-of-alcohols.aspx And there are catalytic methods of ...
1
vote
1answer
41 views

Detecting the concentration of chlorpromazine

Is there a way to detect the concentration of chlorpromazine in a small sample ; ex: human saliva, using electro-chemical analysis? Does the sensor necessarily have to be a bulky piece of lab ...
2
votes
2answers
899 views

Carboxylate “cage” concept

My professor emphasizes the concept of the carboxylate "cage" or the idea that electrons participate in resonance within a carboxylate group such as in the benzoate anion but the electrons in the ...
2
votes
1answer
1k views

Carbonyl carbon electropositivity?

Is the carbon in a carbonyl functional group electropositive? I had a professor tell me so, but I immediately refuted him, because he defined electronegativity earlier as the ability to stabilize ...
6
votes
1answer
2k views

Electrolysis of Beer

Electrolysis of water, means that the water is separated into hydrogen and oxygen. As beer also includes water, I initially thought electrolysis of beer would cause the water to separate, and the ...
9
votes
2answers
729 views

Validity of ionic resonance structures

What's wrong with ionic resonance structures? I asked one professor about them once and all he commented was "I've seen them too, and I think they're wrong." Another professor rejected an ionic ...
1
vote
1answer
790 views

Free rotation of sigma bonds; diastereomer formation; thermodynamic and kinetic products

For the reaction of 1,3-butadiene with DBr (D = heavy hydrogen), I found that several possible products could be formed. Kinetic products A pair of enantiomers is formed. One of the pi bonds ...
7
votes
1answer
5k views

What are chiral environments?

I keep seeing the term cropping up, but cannot seem to find a definition for it. My understanding is that it is an environment in which, when the isomers interact with the environment, the two ...
2
votes
1answer
2k views

Quick way to find magnetic nature of compounds or ions

According to the Molecular Orbital Theory, the method to check whether a given compound is paramagnetic or diamagnetic is to draw the molecular orbitals and then to see whether we have all the ...
0
votes
2answers
204 views

How would one express pemoline in terms of phenethylamine?

Pemoline is a psychostimulant that is no longer used in most countries. Similarly to the psychostimulants amfetamine and methylphenidate I can clearly see a phenethylamine backbone to this compound. I ...
0
votes
1answer
94 views

Determining the amount of chlorine in a swimming pool

I need to determine the amount of chlorine in a swimming pool. How do I get started? What kind of experiment would I need to carry out? What equipment would I need for this experiment?
0
votes
1answer
6k views

Calculating collision diameter with viscosity, but not having the mass given

I've got a homework question i'm stumped on. The viscosity of the ethylene gas was measured at $99.8\times10^{-7}\ \mathrm{N\ s\ m^{-2}}$ at $288\ \mathrm K$. Calculate the collision diameter in $\...
15
votes
4answers
25k views

Which chemical is responsible for making marker ink permanent?

As asked in the question and also, a bonus question: which property of a chemical would make it 'permanent' in terms of markers?
17
votes
2answers
5k views

Dipole moment of cis-2-butene

I need someone to back me up on this before I go confront my teacher: I was doing some analysis of the dipole moment of cis-2-butene. Let's say that the alkyl groups are both on top. Would the dipole ...
11
votes
2answers
7k views

What is the difference between polyethene and polyethane?

The monomer in polyethene seems to drop the $\ce{C=C}$ bond and end up with a $\ce{C-C}$ bond. The polymer chain then looks like $\ce{[CH2-CH2]_{n}}$. If I were to look at that polymer chain I would ...
0
votes
1answer
1k views

Estimating magnitude of percentage and absolute error

Can someone at least give me a hint to push me in the right direction of how to estimate the magnitude of the absolute and percentage errors when using a smaller amount in mL of a substance for a lab ...
1
vote
1answer
1k views

Sodium metal reduction of chloroform

In discussing how best to deuterate chloroform, it occurred to me that we could use sodium metal to reduce hydrogen into hydrogen gas. If this could actually happen, this would be a great thing - we ...
2
votes
2answers
825 views

water vapor vs air (in a balloon)

I poured some water in a balloon, inflated, and tied it up. Over a period of couple weeks, all water in the balloon is gone. But the balloon is still at about 2/3 of original inflated size. I ...
4
votes
2answers
357 views

How to define the atom numbers in unsaturated hydrocarbons correctly according to IUPAC?

I would like to address the compound below. This compound on elaborate elongation would result in this structure. But is the below given numbering correct? I am just wondering that what if the same ...
0
votes
1answer
76 views

Why does the absorbance of Ca decrease in the presence of certain metals?

I'm trying to find a reason for an experimental observation, I noticed that when the absorbance of $\ce{Ca}$ is measured with FAS(flame atomic spectroscopy) that it decreases when metals such as $\ce{...
9
votes
1answer
2k views

Steric effects of a lone pair and piperidine

I know that in piperidine, the lone pair on the nitrogen can occupy either an axial or a equatorial position in the two chair forms. I also read that the axial position for the lone pair is preferred ...
3
votes
1answer
6k views

How can I predict what dissolves what?

Regarding solvents, the only thing I remember from school is my teacher saying: "The same dissolves the same." regarding the polar/non-polar solvents. From this I understand that water is polar ...
2
votes
0answers
664 views

Is Sodium metal more reactive towards an alkyl halide or an alcohol in a protic polar solvent?

Will Sodium metal donate its electrons to bromine in 1,3-dibromopropane or to the hydroxyl group in ethanol in a polar protic solvent? This question comes from a problem: 'What is the major product ...
-2
votes
1answer
3k views

Finding rf value of methyl benzoate

What is the $R_f$ value of methyl benzoate and 3 nitro methyl benzoate in hexane and ethyl acetate?
2
votes
1answer
231 views

What trends affect hydrophobicity in amino acids?

I was wondering if the length of the carbon backbone affects hydrophobicity of amino acids (i.e. longer carbon backbone of side group = less polar = more hydrophobic).
2
votes
4answers
4k views

Conversion of propane to methane [closed]

I had a question in my textbook to convert propane to methane. The basic idea was chlorination in presence of sunlight. However, two products are obtained in this case - namely 2-chloropropane and 1-...
6
votes
3answers
1k views

Could neutralisation of safe chemicals produce dangerous ones?

I'm basically thinking whether I could potentionally poison myself while neutralising strong acid/base by some weak base/acid when I accidentally spill it, touch it or when I'm cleaning reaction ...
14
votes
1answer
15k views

How can I find the symmetry labels of atomic orbitals in a molecule?

What are the symmetry labels for the p and d orbitals of platinum in $\ce{[PtCl4]^2-}$? I understand how to find the point group of a molecule, but am not sure how to use the character table to find ...
5
votes
2answers
5k views

What is the chemistry behind amalgamation?

Mercury can form amalgams with metals, such as gold, however how exactly does the "reaction" if you can call it that take place? My understanding of metal bonds is that the atoms of a metal are ...
-1
votes
1answer
225 views

The stability of a “Di-onol” - carbonic acid - and analogies to cis-nitrous acid

The reaction of carbon dioxide with water yields carbonic acid to some extent (0.4 %) depending on pressure (and temperature). This process, according to @ron, goes through a four-membered ...
1
vote
1answer
2k views

How many Au atoms can be extracted from 0.250 L of seawater?

Gold is present in seawater to the extent of 0.15 mg/ton. Assume the density of seawater is 1.03 g/ml and determine how many gold atoms could be extracted from 0.250 L of seawater. ($\pu{1 ton}=\pu{...

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