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
1k views

How does molecular collision excites the electron?

I have this question for a long time that in LASER when we do the pumping by heating how does molecular collision causes the atoms(molecules) to reach in excited state. E.g. in $\ce{He-Ne}$ laser when ...
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531 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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How can I tell if a molecule is polar or not?

Consider $\ce{PCl3}$, $\ce{CH2Cl2}$, $\ce{HCN}$, and $\ce{SiO2}$. Which of these molecules are polar substances? I appear to be lacking on the concept of "polar substance". I was just studying about ...
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What makes a compound a dehydrating agent?

When a carboxylic acid with low molecular weight is heated with $\ce{P2O5}$ we get the corresponding anhydride. My book says that this reaction happens with dehydrating agents such as $\ce{P2O5}$. I ...
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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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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
224 views

Reaction of Silicon monoxide with alcohols

Elements from the carbon group tend to form compounds with two oxygen's. Let's say I want to produce $\ce{SiO_2}$ out of $\ce{SiO}$ by mixing it with some alcohol, for example: $$\ce{SiO + CH_3-CHOH-...
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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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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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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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Which relatively simple molecules violate the octet rule?

I'm learning how to draw Lewis diagrams. Everything I've read emphasizes the octet rule. However, to the best of my knowledge, that rule only applies to elements in the first three periods. On our ...
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1answer
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Sugar dissolution test

Is there a way to detect whether sugar is completely dissolved in a cup of water other than looking at the bottom of the cup? I was wondering if there is a test or something that can be carried out ...
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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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779 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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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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Why is tetrafluoromethane non-polar and fluoroform polar?

Consider the Lewis dot structures of the molecules fluoroform, $\ce{CHF3}$, and tetrafluoromethane, $\ce{CF4}$:   My first line of thought is that both of these molecules are symmetrical (the ...
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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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Really how rare are hydrogen atoms?

Hasok Chang, a chemist, but perhaps more a philosopher recently published the book Is Water H2O? . Chang used the question and an extensive web of arguments ultimately as a platform to support a ...
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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
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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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657 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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When does hydrogen bonding happen?

What kinds of molecules will experience hydrogen bonding (inter and intra)? Why does it occur for some H atoms but not others?
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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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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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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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What causes spray cans to get cooler when shaken?

I've been searching the web for this phenomenon and surprisingly I found only one post about it. And the reply to this question about canned air begins with words: I don't know about the shaking ...
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Explain the formation of replicators to a layman

I am reading The Selfish Gene by Richard Dawkins. I am on chapter two. He speaks of the observation of the formation of amino-acids when you simulate environmental conditions of primordial earth. ...
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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
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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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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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2answers
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Does Uranium ore count as a mixture?

I'm doing an assignment where we must research the separation of a mixture to obtain a useful final product. I thought about the separation of Uranium from its ore after it has been mined, but I did ...
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How to understand the concept of moles? [duplicate]

I have trouble relating to the mole concept. For example in a question like the following: How many moles of $\ce{K}$ are in 1 mole of $\ce{KOH}$? How is it that in 1 mol of $\ce{KOH}$ there ...
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Amplitudes and phases of transform of an image

I have recorded an image of a large macromolecule and after several types of image analysis, have obtained a rotationally averaged image, that is not quite perfect, but appears to show 6-fold symmetry....
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How to represent a 3D model of cocaine?

For my AP Chemistry class we were told to make a molecular diagram that was "better than excellent" and the rest is up to us (we could choose the molecule and how we wanted to represent it). My group ...
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How to calculate a rough estimate for the volume of a nitric oxide molecule?

I was wondering what would be the best way to calculate a rough estimate for size of a nitric oxide molecule to use in comparison to a box. I was thinking volume would be the best method, but this ...
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Mass of “orange” in 25% orange juice [closed]

Hypothetical question: Knowing that orange juice has 25% concentration of orange. And knowing mass of juice which is 200g. What ...
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7answers
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Are there any good examples of commonly ingested molecules that contain particular toxic individual elements?

In the house on my own and an article popped up on my feed with the following statement: While the Government has insisted the chemical is safe, cadmium is recognised as a cause of lung cancer ...
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Why is O2 enough to form a mole of Oxygen? [closed]

I understand that this is the most basic knowledge of moles, however I'm still unsure - according to easy research, $\ce{O2}$ forms a mole of Oxygen. As a mole is $6.022*10^{23}$, exactly what on the ...
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What's the reason for discrepancy between DFT calculated image and NC-AFM-acquired one in this article?

Looking at the images in this article, I've noticed that the molecule electron density images showed as calculated via DFT look very symmetric, while those obtained by NC-AFM appear somewhat distorted....
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Is oil shinier than water? Why?

The physics part: The part that talks about being shiny, I agree, is mainly physics. But proceed in my question, and you'll see how it's a chemistry one. We know things are shiny if they either ...
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1answer
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Calculating the volume of 1 mole of liquid water

I am doing some rough calculations to test my understanding of elementary chemistry. In what follows, I calculate the volume of one mole of liquid water at about $\pu{4 ^\circ C}$ and $\pu{1 atm}$: ...
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1answer
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Do molecules with carboxyl groups have properties of carboxyl's sub-functional-groups?

We're learning about functional groups of different organic molecules, and there are some I'm confused about: carboxyl, carbonyl, and hydroxyl. I was looking online but I couldn't find a direct answer ...
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How was the diatomic nature of many common gaseous elements originally determined?

How did scientists find out that $\ce{Cl2, H2, O2}$ atoms have a two-atomic molecular structure ?
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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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Molecular structure of all periodic table element molecules exceptional cases etc [closed]

I am searching about some basics in chemistry. I was looking for the molecular structure of all periodic table element molecules. eg: Hydrogen molecule: as $\ce{H2}$; structure: I was able to find ...
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Can a single monomer be a macromolecule? If so, when?

In our science class, we're learning about the four fundamental macromolecules in every living organism: carbohydrates, proteins, lipids, and nucleic acids. Our class definition of a macromolecule ...
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How to know whether s-p mixing will happen in heteronuclear molecules?

How do I know whether s-p mixing would occur in some diatomic heteronuclear molecules like CN, CO, NO etc?
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Using MO theory, give an explanation for the C-C bond length in cyanogen

1. The problem statement, all variables and given/known data 2. The attempt at a solution I know that the MO diagram for CN- is this: I am unsure how to draw the MO diagram for cyanogen. I know ...