An electrically neutral entity consisting of more than one atom (n > 1). Rigorously, a molecule, in which n > 1 must correspond to a depression on the potential energy surface that is deep enough to confine at least one vibrational state. This tag should be applied to question about certain ...

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28 views

Question on Mole Concept [closed]

A compound contains 8% oxygen and 4% sulphur. What is the minimum molecular weight of the compound? Please Explain.
0
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1answer
36 views

A problem on rate of diffusion

At a particular temperature and pressure it takes just 8.256 minutes for a 4.893 liter sample of Neon (Ne) to diffuse through a porous membrane. How long will iodine diffuse in similar conditions? ...
3
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0answers
15 views

Steric hindrance of an unbonded electron pair

This question is half inspired by this question, and half inspired by the structure of molecules like hydrazine and hydrogen peroxide. When I was looking at the aforementioned molecules, I started ...
2
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1answer
50 views

How does molecular orbital theory explain CH4?

I have understood the formation of $\ce{CH4}$ by valance bond theory, but I'm having trouble understanding it through molecular orbital theory. The energy level diagram of molecular orbitals of ...
18
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1answer
946 views

Why do the atoms in molecular models have the colors they have?

Molecular models are a great tool for visualizing a molecule in three-dimensional space. These models even appear on the web (practically every chemical's Wikipedia page), and there is a very specific ...
0
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1answer
35 views

Model of London forces and Hydrogen Bonding; the question is carried on forward, partially, as a personal question, from another question [closed]

Does Model of London forces and Hydrogen Bonding are themselves complicated and require multiple sub-models and assisted theories to explain its correctness. I asked this question in the form ...
3
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1answer
43 views

Shape of Allene Molecule

Allene, $\ce{H2C=C=CH2}$, has two $\ce{=CH2}$ groups perpendicular to each other. This is the same as hydrogen peroxide's $\ce{H}$ atoms. Is there any reason why they adopt the perpendicular ...
4
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1answer
37 views

Dipole moment of molecule (isolated vs in solution)

Would you expect a dipole moment determined in solution to be different from that in an isolated molecule? If so, why?
2
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1answer
35 views

How to quantize the shape of a molecule?

I am looking for numbers which tell you something about the 3D shape of the molecule, and is also easily calculated. One of these is the acentricity factor. I am aware of this one. My problem is you ...
1
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1answer
34 views

Colligative properties

I have some problems with these properties. 1) Lowering vapor pressure and boiling point. It happens because the solute molecules take space in the surface of the liquid so a lower number of the ...
2
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1answer
46 views

Do absorbances of different compounds at one wavelength sum up?

Question on my practice exam. The answers to the questions were not released, otherwise I could work backwards to figure out how to solve it. As it stands, though, I can only guess the method to solve ...
1
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0answers
26 views

why the formula of coca cola can not be find using chemistry? [duplicate]

i mean we have SPECTROSCOPY to stablish what molecules make a compound and also we have advanced chemistry so why is SO HARD to find the formula of coca cola ? simply buy a bottle examine it to ...
16
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1answer
108 views

Do symmetric hydrogen bonds in neutral molecules exist?

As far as I know, there have only few truly symmetric hydrogen bonds been observed. Unquestionable is the existence of it in the bifluoride ion, $\ce{[F-H-F]-}$, see also here. There are a couple of ...
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1answer
68 views

How to determine the molecular formula of a compound given percentages of the elements?

If the molecular mass of a compound is given as 'm' and it consists of two elements 'A' and 'B'. The compound it composed of x% of 'A' and y% of 'B'. How do I find the molecular formula of the ...
15
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1answer
364 views

Why is a S-S bond stronger than an O-O bond?

I'm wondering why exactly the single bond between two sulfur atoms is stronger than that of two oxygen atoms. According to this page, an $\ce{O-O}$ bond has an enthalpy of $142 \rm~\frac{kJ}{mol}$, ...
3
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2answers
47 views

What exactly happens when vegetable oil is partially hydrogenated?

My current assumption is that partial hydrogenation requires a polyunsaturated fat, because partial implies at least one but not all, which means there must be at least two double bonds in the fat, ...
8
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1answer
206 views

Materials with solid volume greater than liquid volume

Water has a solid volume greater than its liquid volume. This question is in two parts. 1) Are there other materials that have solid volumes greater than liquid volumes? 2) What about the structure ...
0
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0answers
21 views

Electrical driving force

The question is kind of related to chemistry. Electrical driving force happens between ions when negative or positive charged ions is concentrated on a side more than the other. The teacher ...
0
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0answers
37 views

Strength of London Dispersion Forces - Why do rings have stronger dispersion forces? [duplicate]

My textbook says, Rings can be stacked on top of one another to give rise to stack of closely spaced rings, hence they have overall stronger dispersion forces. Ring > Linear > Branched With similar ...
0
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1answer
59 views

How can I search molecules by constituent atoms

Given a set of atoms, I would like to find (some / the most common) molecules that include only (some/all) atoms of the set. Is there any online search engine that can do this? E.g. Atoms={C,H} ...
3
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0answers
51 views

How to determine the empirical formula given mass percentages of the elements and the molecular weight?

A compound has $67.3 \% \rm~C,4.62 \%~N,6.93 \%~ H$ and O. Determine the molecular formula of the compound knowing its molar mass is $283\rm~\frac{g}{mol}$. My solution : The percentage for the ...
1
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1answer
45 views

Can you create artificial molecules with a machine?

Is it possible to create molecules with machines? For example: you shoot one Oxygen-atom (O) on one diatomic Hydrogen ($\ce{H2}$) to create one water molecule ($\ce{H2O}$).
3
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1answer
71 views

Stability of CN molecule

The CN molecule has been observed spectroscopically in comets where pressure has been estimated to be as low as $10^{-10}$ mm Hg. Draw a Lewis structure for CN. Suggest an explanation as to why this ...
4
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1answer
65 views

How was the composition of DNA studied before the knowledge of its structure?

In a large polymer molecule (such as a DNA chain) which is made from multiple component monomers containing many atoms, how was it determined that the chain was made up from the four groups of ...
1
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1answer
40 views

In which cases do you say “oxide” when naming a molecule?

Based on the names of following molecules I got quite confused about the correct nomenclature: $\ce{NaHCO3}$ $\ce{K2SiO3}$ $\ce{PbCrO4}$ In none of the above molecule names you ever say "oxide" ...
5
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3answers
636 views

Is there a way to use free software to convert SMILES strings to structures?

So far I've been unsuccessful in finding an open source tool that will convert a large number (>100k) of SMILES strings to a chemical structure. Is this really only solved by commercial applications? ...
4
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1answer
408 views

Why is NO2 formed when N valency is 3

Sorry if the question is silly but this is troubling me more than enough. Here's what I know about chemical formula: Reverse the valencies of the combining elements. But in this case, $\ce{NO2}$ is ...
1
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2answers
95 views

Shouldn't all of group 16 form double bonds? [duplicate]

I notice that out of all of group 16 oxygen is the only element that can form a double bond. Why is that because shouldn't all of group 16 be able to form a double bond and be diatomic because they ...
1
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1answer
39 views

Can $\ce{CO_2}$ be separated into $\ce{C}$ and $\ce{O_2}$? [duplicate]

I am a grade 8 student and I need to do some background research for a science project of our choice, and my project relies on if $\ce{CO_2}$ can be separated into a $\ce{C}$ and $\ce{O_2}$. So, Is ...
4
votes
1answer
81 views

How is a side-group that contains a double bond named?

In my chemistry lecture, we are working on the naming and nomenclature of organic molecules. When we got to the naming of alkenes and alkynes, we were told that the functional group had to be in the ...
0
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1answer
60 views

Are the collisions between the real gas particles perfectly elastic?

Well my question is simple, if two real gas particles are colliding (head on collision) then will the kinetic energy will be conserved i.e. will it be a perfectly elastic collisions?
3
votes
2answers
64 views

Is this graphic of molecules correct?

First off, huge fan of chemistry, not a chemist – do be nice :D Would an image like this make sense as an infographic for the molecular composition of the air? I especially wonder if the different ...
2
votes
1answer
49 views

What would carbon-oxygen polymer be called?

So I have a chain molecule made of carbon and oxygen, and I'm not sure what it would be called. Would any of you lovely fellows be able to help me? The best name I've been able to come up with so ...
1
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0answers
45 views

Can one component of a mixture penetrate the skin if the whole mixture cannot?

There's a general rule that says that compounds under 500 dalton are able to penetrate the skin without any special vehicle (such as ethanol). I've started using castor oil, which contains different ...
14
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1answer
228 views

Symmetrize nearly symmetric molecule

In the overall good paper of Beruski et. al.,[1] an algorithm of how to symmetrize an "almost symmetric" molecule by symmetrizing the distance matrix is given for the example of Methane. The ...
1
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2answers
48 views

Is water a heterogeneous molecule? [closed]

My question is based upon the statement found here: an element may be homogeneous on a larger scale, compared to being heterogeneous on a smaller scale. This is known as an effective medium ...
0
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1answer
47 views

Which of the following samples is impossible? [closed]

Given the following atomic masses: Aw(Al) = 26.98 amu Aw(O) = 16.00 amu Aw(C) = 12.01 amu Aw(H) = 1.00 amu Aw(Fe) = 55.85 amu I'm trying to determine which of the following doesn't make sense, ...
1
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1answer
144 views

Structure diagrams indicate plausible structures? [closed]

Structure diagrams have a hexagonal, "chicken wire" shape, which leads to more elegant representations of some molecules than others. For example, the following diagram must deviate from the usual ...
0
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3answers
94 views

Teaching: Two elements that make XY2 and XY4 molecules

I am not a chemist, but I will be explaining chemistry to some third-graders. I want to give the example of how different things can be made of the same parts, but arranged differently. My "real ...
2
votes
1answer
294 views

Why is Iodine's melting point is lower than water?

My teacher told us that melting point of Iodine is lower than Ice as it is a Simple molecular structure bonded by weak van der waals forces. However I gooogle and found out its melting point is ...
1
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0answers
66 views

positions of a methane molecule with carbon atom at the origin [closed]

Let $\text{CH}_4$ be the molecule of Methane: The four hydrogen atoms form vertices of a regular tetrahedron with the carbon atom in the center of the regular tetrahedron. Here we regard all atoms ...
1
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2answers
6k views

What is the difference between “molecular mass”, “average atomic mass” and “molar mass”?

I don't understand the difference between "molecular mass" and "average atomic mass". They seem like the same thing to me. Is it that average atomic mass is just the weighted average of the ...
0
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1answer
154 views

Molarity of Sodium Ion Concentration (and some really weird answers…)

I know how to do this problem really easily but I don't know why my answer is wrong... The problem is: What is the molarity of sodium ions in a solution prepared by diluting $250\ \text{mL}$ of ...
3
votes
1answer
156 views

Is there any molecule visualizing software for Python?

I am looking for a free and open-source software written or wrapped for Python that would simply allow me to generate bunch of figures (in eps, jpg, or pdf format) from a set of xyz files, e.g. water ...
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1answer
86 views

Molecules aren't the same as atoms?

Question is simple but tricky, for example my chemistry teacher says that preservatives on food for example Nitrate N3 are not good in excess for your body (like everything else), but if Nitrogen is ...
3
votes
1answer
106 views

If you can smell something does that mean that this thing loses molecules?

When you can smell something there must be some molecules in your nose which signalize the smell in your nose. Does that mean, that e.g. a cheese is losing molecules which fly into your nose? And does ...
0
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1answer
46 views

Good measures ot atomic size

I was looking up the Lennard-Jones parameter $\sigma$ (which, to my understanding, is a measure of molecular size) when I was surprised to discover that the value for the $\ce{N2}$ molecule (3.667 Å) ...
15
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1answer
789 views

Are long Oxygen molecules possible?

Are large oxygen containing molecules possible? Either large rings, or chains with hydrogen atoms at the ends. Like this: $\ce{H-O-O-O-O-O-O-O-O-O-... -O-O-O-O-O-H}$
1
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1answer
71 views

At what point does Avogadro's law not apply?

A mole of hydrogen gas takes up 22.4 L, but so does a larger molecule like $\ce{CO2}$. Methane ($\ce{CH4}$) is an even larger sized molecule, but a mole of it will still take up 22.4 L. I would assume ...
2
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1answer
90 views

Molecules made of molecules?

When a molecule of water ($\ce{H2O}$) and a molecule of hydrochloric acid ($\ce{HCl}$) react together, would they become a molecule made of molecules? What's the name for such thing? How would it be ...