Questions tagged [molecules]

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 molecules or a class of them.

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1answer
219 views

Find empirical formula when individual masses are known

I'd like to illustrate my question with an example: Imagine nickel reacts with fluoride and you start with $0.766\ \mathrm{g}$ of nickel, an unknown amount of fluoride and you end with $1.261\ \...
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1answer
184 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 far ...
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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 ...
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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 ...
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1answer
104 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 ...
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3answers
875 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 world"...
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1answer
527 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 ...
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How do the molecules know the future? How do they proceed to form “Most Stable” compound?

I'm tutoring few students for Chemistry. During the course, I many times use the phrase "Out of these possibilities this one is stable. So it is formed". I get questions like, "How do the molecules ...
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1k views

Can you determine whether a compound can form given particular elements?

Say you are given a set of particular elements, such as Dy, C, I, Er, P. Is it possible to determine whether a compound exists with all of the given elements and no more? If not, is it possible to ...
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Invariants in chemistry used for model selection

What invariants related to geometrical structures that describe molecular geometry are used in chemistry? Explanation: Here, Electronic model with highest prediction rate…, one can learn about ...
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2k 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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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 $0....
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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 ...
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Do noble gasses besides Helium form diatomic molecules at low temperatures?

I know that at extremely low temperatures (mK and lower), Helium can form diatomic molecules. Do the other noble gasses also form molecules at extremely low temperatures?
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1answer
94 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) ...
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1answer
328 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 ...
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6k views

Use of osmosis to measure molecular weight of macromolecules

How can osmosis be used to measure molecular weight of macromolecules ? Is it applied practically ?
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1answer
546 views

How did the first amino acids appear on Earth?

Is there proof or a theory that shows that the first amino acid syntheses on Earth were influenced by a change in heat, gravity, radiation, or something similar?
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9k views

Chemical composition of petrol

What is the chemical composition of petrol? What are the molecular available in petrol? Some time which is marked with 95% octane. So what is the remain element occupied 5%?
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1answer
532 views

Find oxidation number of a metal in a compound

Calculate the oxidation number of $\ce{Fe}$ in $\ce{Fe2O3}$. Alright. So we have a metal and an non metal. This means that iron will lose electrons and give them to oxygen. So it will be a positive ...
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1answer
450 views

Can molten sugar also rotate polarized light as sugar water does?

It is well know that the sugar water can rotate the plane of linearly polarized light, so light bends when travelling in sugar water. However, do the liquid state of sugar but not the sugar solution ...
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1answer
891 views

Establish the formula of an oxide of chromium

An oxide of chromium used in chrome plating has a formula mass of 100.0 u and contains four atoms per formula unit. Establish the formula of this compound, with a minimum of calculation. ...
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323 views

Interaction radius of a molecule

What is the most commonly used radius of an atom or molecule to describe the area that must touch another area of another molecule for the two to react. Is there one radius that always works or does ...
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1answer
510 views

Empirical and molecular formula

I was doing a homework assignment and I got the following question wrong because I was supposed to multiply the empirical formula by 3 to get the molecular formula of $\ce{C6H10S2O}$. I put $\ce{(...
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1answer
187 views

Only-C chain molecules

Are (cyclic) $\ce{C}$-chain molecules as in the picture likely to occur or do they exist at all? and so on... EDIT: I'm considering only double bonds between $\ce{C}$ atoms. This rules out most ...
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1answer
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Why six C atoms are usually seen in cyclic compounds?

When it gets to Carbon-based molecules, one very possible structure when there are more than six C atoms is the hexagon; though not mostly perfect, it emphasizes that six Carbon atoms tend to bond ...
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4answers
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Differences between H-H-O and H-O-H

I'm not an expert. In simple words how do they differ: $\ce{H-H-O}$ and $\ce{H-O-H}$ molecules?
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470 views

Why are H2O asymmetric while CO2 is not? [duplicate]

What is the reason for water molecules $\ce{H_2O}$ being asymmetric while other molecules like $\ce{CO_2}$ being completely symmetric? See the pictures below: In both case there is an electronegative ...
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2answers
184 views

Are all molecular structures symmetric?

Are all molecular structure symmetric either in relation to a plane within itself or in relation to other molecules? Are there any completely asymmetrical structures when looking at molecular geometry?...
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2answers
781 views

Are these 3 molecular structures of ammonium bicarbonate the same?

Are these 3 molecular structures of ammonium bicarbonate the same? A: B: C:
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550 views

What does the 129Xe NMR spectrum of XeOF4 look like?

What will the $\ce{^129Xe}$ NMR spectrum of $\ce{XeOF4}$ look like? I know that its electron pair geometry is octahedral, and the molecular pair geometry is square pyramidal. I believe that the ...
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1answer
593 views

How does the pyramidalization effect the bonding angles in a distorted octahedral environment?

This is a follow up on "Generally Octahedral - Meaning?". Since Dissenter asked in the comments to my answer: I'm not sure why the $\ce{F_{eq}-S-F'_{eq}}$ bond angles would be compressed, even if ...
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1answer
97 views

Calculating the number of molecules remaining

This is the question in my text book: From $392\:\mathrm{mg}$ of $\ce{H2SO4}$, $1.204 \times 10^{21}$ molecules are removed. How many moles of $\ce{H2SO4}$ are left? What I tried doing: First I ...
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How long do the bonds in a molecule hold under nominally stable conditions?

Disclaimer: I am not a chemist I was just drinking my Ice Age mineral water which is 'untouched since the Ice Age' and wondered if the bonds formed in each molecule have remained intact for all those ...
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First ionization energy of hydrogen molecule

If we have the dissociation's energies of hydrogen molecule $\ce{H_{2}}$($D_{0}$) and the corresponding molecule ion $\ce{H_{2}^{+}}$ ($D_{1}$) together with the first energy of ionization of hydrogen ...
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Why do different substances have different boiling points?

For example, why does for example oxygen turn into gas at a much lower temperature than water? Does it have anything to do with the molecular structure? A water molecule does have a more complex ...
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1answer
2k views

Equivalent hydrogens in 2,3-dimethylbutane

So while calculating for the relative yield of monochlorination for 2,3-dimethylbutane, I was counting the primary hydrogens, I counted 6, but in fact it was 12. Why is it 12? How do you find ...
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1answer
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What causes “stringy” melted cheese (and similar behavior in other materials)?

I was wondering about this. What is the physics underlying the "stringy" consistency of melted cheese? That is, when the melted cheese is hot, and it is pulled apart, it forms strings of cheese. This ...
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1answer
663 views

MO for $N_2^{2-}$

Could someone please show me the MO diagram for $\ce{N_2^{2-}}$? What I did was since N has 5 valence $\ce{e^{-}}$, then $\ce{N_2}$ must have 10, and $\ce{N_2^{2-}}$ must have 12. And $\ce{N}$ has $s$ ...
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410 views

What radius best represents reaction distance?

Molecules must be within a certain distance for a reaction to begin as well as satisfying a myriad of other factors. Whilst the exact distance varies from reaction to reaction, is their any distance/...
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1answer
2k views

Why might two different chemical structures smell the same?

From what I understand, it is the functional group attached to a structure that determines the odor it will give off, for the most part. Which explains why two similar molecules, except for their ...
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Diatomic Molecules/Elements

What is the difference between diatomic molecules and elements? Also, If oxygen is element of a single atom, then what makes it a diatomic element? But, then I read that a single oxygen atom can ...
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1answer
67 views

Amount of substance of a molecule in a solute the same as amount of substance of constituent elements?

I’ve done absolutely no chemistry since high school. Now, 16 years later, I’ve been asked to look at some chemical analyses and I’m having trouble! Context: I’ve got a series of spectroscopy ...
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What is the mean curvature of nitrates and nitrites?

I am reading the book Soft Matter Physics - Synthetic and Biological Self-Assembling Materials from Hamley and particularly page 201. I started to think how this packing occurs in case of molecules ...
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1answer
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Is this a possible explanation as to why sigma bonds are stronger than pi bonds?

Sigma bonds form due to the axial overlap of two orbitals whereas pi bonds form due to their lateral overlapping. Since the former is more effective, we can say that sigma is stronger than pi. We mean ...
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1answer
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How exactly do alcohol molecules dissolve in seawater?

The book "Lehrbuch der anorganischen Chemie" by Arnold F. Hollemann on page 47[link here][1] states that dropping 0.8g Alcohol (M = 46g/mol) in a sea or ocean would result in every litre seawater ...
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1answer
170 views

How to change CO₂ to a less polluting gas?

I want to change $\ce{CO2}$ coming out of the tailpipe of a car to some other compound that is considerably less harmful to the environment with a filter of some sort. What are some ways that this is ...
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2answers
11k views

Why does ammonia have sp hybridization?

Apparently it has $sp^3$ hybridization, but I don't understand why. Ammonia ($\ce{NH3}$) seems to me to not require $sp$ hybridization because all of its bond lengths are already equal. It has 3 ...
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1answer
788 views

How can it be certain that some bonds are 180 degrees?

Take acetylene, for example. It is defined that the two outer bonds are at 180 degrees. How is it possible to theoretically define all $\ce{C-H}$ bonds in acetylene as being 180 degrees?
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Has the molecular diatomic oxygen trianion been observed or predicted?

Has diatomic oxygen ever been observed with a 3− charge, i.e. $\ce{O_2^{3-}}$? Have any ab intio calculations been done on this ion? Update: Just to summarize some of the answers below and add my ...