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What makes a molecule a polyatomic ion?

I checked the Wikipedia page, but it did not seem to provide a very intuitive explanation. What distinguishes a molecule such that it behaves like a polyatomic ion? I understand that it is a ...
3
votes
2answers
3k views

Why doesn't water play a role in reactions in aqueous reactions?

$$\ce{Ba(NO3)2(aq) + Na2CO3(aq)}$$ In the above reaction both the substances are in water, however water plays no role in the reaction. Why is it that although water is present in the reaction, it ...
2
votes
1answer
4k views

Is “ice point” the same as “freezing point”?

I am using an old book and they almost use both terms interchangeably sometimes. Do they mean the same thing? Similiarly for "steam point" and "boiling point"
1
vote
1answer
600 views

Why is it called “carbonation”?

Why is it referred to as "carbonation" and we drink "carbonated" beverages when carbonate is $\ce{CO3}$ while $\ce{CO2}$ (carbonite?) is present in carbonation?
5
votes
1answer
1k views

Is there a similar characteristic of the lanthanide contraction in the other transition metal groups?

Basically, does the lanthanide contraction also occur with the 4d, 6d groups as well? I am at a lack of understanding in this topic, I am just wondering what specific elements does this jump in a ...
1
vote
1answer
5k views

Percent composition of nitrogen in fertilizer

The question was posed as follows: Fertilizers supply the essential elements, nitrogen, phosphorus and potassium for plant growth. A bag of fertilizer contains 500g of ammonium sulfate, $ \small \...
8
votes
3answers
5k views

Methane seems to dissolve more readily in cold water. Why?

When you are diluting air in the system and/or properly evacuating it, you must consider water temperature. Methane is completely dissolved in water at 42 degrees Fahrenheit (5.5 C) but can be ...
5
votes
1answer
177 views

Simulation of a particle and chemical molecule

I am currently studying the basics of simulation and want to try out some experiments. It is a known fact that gold nanoparticles can bind to chemical groups which contains thiol (R–SH group). I want ...
5
votes
1answer
948 views

Does “covalent” AgCl (aq) exist and if so, how to quantify its concentration?

I am reading Ionic Equilibrium by James N. Butler. Using silver(I) chloride in excess aqueous chloride as an example it speaks of several forms: $\ce{AgCl (s)}$ i.e. the ionic crystalline salt, $\ce{...
26
votes
2answers
32k views

Why is water a dipole?

Water ($\ce{H2O}$) is a dipole. The reason why is simply because it is not symmetrical, there are more electrons on the oxygen side than on the hydrogen side, and the electronegativity of oxygen. But ...
3
votes
1answer
3k views

How to extract pure caffeine from tablets?

I have some caffeine tablets and I want to extract the pure caffeine from the rest of the ingredients (caffeine 200 mg. Inactive ingredients in order are corn starch, dextrose, dicalcium phosphate, D&...
5
votes
2answers
1k views

Why must an oxidizer not touch rubber?

Why is it that oxidizers (specifically $\ce{KClO3}$) are at risk of causing a fire when they come into contact with the rubber stopper used to contain them in their container, but can be slowly heated ...
8
votes
1answer
58k views

Calculating the heat capacity of a calorimeter

I've been struggling with this problem that I can't seem to figure out. I think I know how to solve it but I think there's missing information. The combustion of 1 mole of glucose $\ce{C6H12O6}$ ...
7
votes
1answer
1k views

What determines the electronegativity of an element?

Is it possible to work out without post-Bohrian mathematics?
4
votes
1answer
5k views

Inherent error in mass and volume?

In one of my chem classes I had to do a lab that involved finding the mass and volume of a substance. I did three trials and for my mass I got 9.3g, 9.3g, and 9.4 g. For my volume, I got 9.7ml, 9....
21
votes
2answers
222k views

Will alcohol or soap damage plastic or rubber?

I have read conflicting advice on various sites about the appropriate methods for cleaning plastic and rubber items and would like to ask people who actually know what's going on what they would ...
7
votes
1answer
231 views

What is the 'ancestral term' in the LS coupling scheme?

On the physics.nist.gov site: http://physics.nist.gov/Pubs/AtSpec/node06.html The table titled "Atomic structural hierarchy in LS coupling and names for the groups of all transitions between ...
9
votes
0answers
452 views

multielectron spin-orbit coupling and energy level

For multi-electron atoms for which the Hamiltonian (including the spin-orbit coupling) reads $$H=\sum_i T_i-Z\sum_i V_i+\sum_i V_i^{\text{s.o.}}+\sum_{i>j}V_{ij}$$ The $T_i$ are the kinetic ...
5
votes
2answers
1k views

Is there an alternative to the half-reaction method to solving red-ox reactions?

The equation for the reaction between a permanganate and iron(II) ions in acidic solution is: $\text{MnO}_4^- + \text{Fe}^{2+} \longrightarrow \text{Fe}^{3+} + \text{Mn}^{2+}$ My book, as well as a ...
19
votes
2answers
501 views

Can molecules diffuse upstream when emptying a cup of tea?

I was drinking some tea, and I randomly decided to pour some into the toilet in an unbroken stream; can particles travel "upstream" quickly enough to reach the mug of tea? How fast can diffusion occur ...
8
votes
2answers
3k views

Is there any scenario in which the size of a molecule increases due to an increase in temperature?

Take an ice cube for example. Heat is applied in a closed container until it is vaporized completely. Will the molecule's size be larger (on average)? Is there a substance that you know of that has ...
1
vote
1answer
844 views

Do dishwashing detergent and stain remover powder/stick have the similar ability to remove collar rings?

For yellow rings on shirts caused by skin grease or sweat: Some recommended to use an "Oxyclean" stain remover or stain remover stick for cleaning. Some recommended to use dishwashing detergent to ...
2
votes
2answers
183 views

Are words on my T-shirt removable? [closed]

I wonder if the words on my T-shirt are removable? If yes, what kind of (chemical or physical) ways are there? They look like paints on the cloth, as the letter "C" has become blurred in the way ...
6
votes
2answers
147 views

Why do collisions in elementary reactions of higher-orders appear to be more likely?

So we are told that a unimolecular elementary reaction has a rate law of $k[\text{A}]$ where a termolecular reaction with three unique reagents, $A$, $B$ and $C$ has a rate law of $k[\text{A}][\text{B}...
7
votes
1answer
714 views

What is known about the phase of matter at very high temperature and enough pressure?

Are there theoretical reasons for or against the existence of materials that will not become solid at some fixed, sufficiently large temperature when enough pressure is applied? Or is this even the ...
1
vote
2answers
2k views

deduce chemical properties of a compound from elements

If we know the properties of two elements e.g Oxygen and Hydrogen. We know the following properties sound speed boiling point melting point refractive index etc. given that information, is it ...
6
votes
5answers
13k views

Is tin and tinware toxic?

I tried to find info on tin toxicity but there is not much. Wikipedia here says that it is not very poisonous; but there could be cases. My question is: is it dangerous to say have a coffee boiled ...
4
votes
1answer
3k views

Moment of inertia for a triatomic molecule

What does the moment of inertia for a molecule mean? How is it useful? Most importantly, how would I go about solving it for a triatomic molecule?
12
votes
1answer
1k views

Isolating salt from sea water using filters

Could a filter be used to isolate salt from sea water? Could we say that the water molecules are smaller than the molecules of salt dissolved in the water. I have no relation to chemistry or physics, ...
13
votes
2answers
15k views

Why are alcohols with longer chains less polar?

In my self-study, I recently came across the following question: "Choose the solute of each pair that would be more soluble in hexane ($\ce{C6H14}$). Explain your answer. (a) $\ce{CH3(CH2)10OH}$ or $...
0
votes
1answer
562 views

Product/(s) of the following reaction

I was wondering what the product will be in the following reaction: $$\ce{H3COOCH3 ->[\ce{H+}]} \:?$$ I was thinking about $\ce{CH3COOH}$ being a product but I do not know the mechanism.
3
votes
1answer
6k views

Reaction between potassium permanganate, alum, and sodium hydrogen sulfite

When I was a teenager, I played with a chemistry set. I tried adding potassium permanganate, alum, and sodium hydrogen sulphite (not sodium hydrogen sulphate) to water. Upon adding the third ...
1
vote
1answer
104 views

Methods: Does failing at intermolecular properties mean the same for intramolecular properties?

Let us consider the following: 1.) Method X fails at describing intermolecular non-covalent interactions. 2.) Method X excels at describing molecules of type Y. 3.) Method X ___?___ at describing ...
8
votes
1answer
173 views

Why would the loss of H₂ to space mean that the Earth's geochemistry would be based on acid/base reactions?

I am reading a paper[1] that contains the line: Most of the $\ce{H2}$ in the Earth's mantle escaped to space early in the Earth's history; consequently, the overwhelming majority of the abiotic ...
7
votes
2answers
37k views

Oxidation number for nitrogen in ammonium sulfate [duplicate]

I'm trying to find the oxidation number of $ \ce N$ in $ \ce{(NH4)2SO4}$. The answer is supposed to be $-3$ but I can't figure out the logic behind this.
10
votes
1answer
8k views

What is 'autogenous pressure'?

Compound 1 was hydrothermally synthesized under autogenous pressure[1] I've seen this term used a few times, but with no real explanation of what it means forthcoming. I suspect it refers to the ...
17
votes
5answers
34k views

What is the chemical structure / hybridization of sulfuric acid?

I was looking at the chemical structure of $\ce{H2SO4}$. Intuitively, I would have expected this molecule to be square planar in accordance with $p^2d^2$ or $sp^2d$ hybridization, but instead it is ...
7
votes
3answers
2k views

Why does cesium have a positive electron affinity?

When an electron is added to cesium, why is energy released?
5
votes
1answer
203 views

Modeling perturbations of a quantum mechanical system

I'm wondering how to properly perturb a quantum mechanical system. I'm looking for a way to express the return to equilibrium of such a perturbed state, where the perturbation is in the Hamiltonian. ...
8
votes
1answer
1k views

Very slow chemical clock reaction

I'd like to preface this with a declaration of my understanding that this is not necessarily possible. I was wondering if anyone knew of a chemical clock reaction where the period before the first ...
16
votes
3answers
4k views

Modern alternatives to Gaussian [closed]

Specifically, I'm curious if there are any programs which come close to Gaussian in breadth but also take advantage of things such as GPU processing. There's a page on wikipedia that goes through ...
2
votes
0answers
295 views

Spectral analysis of periodic table of elements in time domain

I'm trying to get the spectral analysis data of the periodic table of elements in the time domain format or find a site that has the data in the time domain format. All the sites I know have the data ...
21
votes
2answers
2k views

Is there a simple way to get the circular dichroism of a molecule from its structure?

Are there any heuristics to get the relative absorbtion of left and right circularly polarized light by a molecule from its molecular structure? Is it even possible to predict which polarization is ...
6
votes
1answer
105 views

What legal guidelines exist for completeness of a Materials Safety Data Sheet?

I know that the answer to this question will vary by country, but some aspects must be similar amongst those countries that have authorities overseeing chemical and industrial hygiene. The Wikipedia ...
3
votes
1answer
10k views

Can acidic conditions break disulfide bonds

I am denaturing a protein using organic solvent and acid (49:49:2% water:methanol:acetic acid), but I want to maintain the disulfide bonds. My chemistry knowledge isn't good but disulfides are broken ...
2
votes
1answer
2k views

Why don't atoms with expanded valence shells have a formal charge?

I'm working through Chemistry - Principles and Practice, 3rd Edition and I have few complaints so I don't think it's the text. At one point, I was asked to draw the Lewis structure, with formal charge,...
16
votes
2answers
20k views

How to properly dispose of sodium…or store it properly

While performing an inventory of my school's chemical storage closet today, my fellow teacher and I found some sodium tucked away in the back corner of our flammables cabinet. One container appears ...
7
votes
3answers
3k views

Which of the following possesses the highest energy electron?

Which of the following possesses the highest energy electron? $\ce{Br-}$ $\ce{Ca^2+}$ $\ce{Cr+}$ $\ce{As}$ Don't bromine and arsenic have equally high energy electrons (i.e. in ...
5
votes
1answer
540 views

What does the reaction of chromium with ozone form?

I know almost nothing beyond 10th grade chemistry. I'm trying to name a web application, and was wondering what the products are of a reaction between the element Chromium and the gas Ozone (...
5
votes
1answer
935 views

How can I identify and neutralize the chemical leaching out of new nitrile gloves?

I have a few cases of brand-new, nitrile gloves of a type and vendor that used to be good. But apparently, the vendor has moved manufacturing to a different country and outsourced customer service to ...

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