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1answer
209 views

Spontaneous inequilibrium in a gas in an isolated system?

Can an isolated system(of several phases) in equilibrium by itself move out of equilibrium? if a system contains for example an inflammable gas dispersed with another combustible gas such that the ...
42
votes
5answers
8k views

How can antibonding orbitals be more antibonding than bonding orbitals are bonding?

In molecular orbital theory, the fact that a bonding and antibonding molecular orbital pair have different energies is accompanied by the fact that the energy by which the bonding is lowered is less ...
6
votes
2answers
5k views

Spontaneous explosion of a bottle containing alcohol and milk

A friend of mine gave me a bottle of home-made liquor which is a concoction of pure alcohol and sweetened milk. I accepted his gift happily and then I put the bottle in my cocktail cabinet. After an ...
3
votes
3answers
12k views

Homemade preservative for natural aloe-vera gel?

I suppose this question can be extrapolated to food in general, but it is the case that I would like to know if there are any methods that would help me to keep the aloe gel fresh, i.e. avoiding it to ...
1
vote
1answer
67k views

How does the reaction Mg + O₂ → MgO occur? [closed]

$\ce{Mg + O2 → MgO}$ Magnesium, oxygen and magnesium oxide form the above equation. How? What do I need to learn to do this? atomic numbers/ valencies?
3
votes
1answer
436 views

Is there a specific term for reactions of the form A + B → C + D?

I'm working with an abstract model of chemical reaction networks. In this model, some of the reactions have the form $\ce{A + B <=> C}$ and others have the form $\ce{A + B<=>C + D}$. I'm ...
6
votes
1answer
547 views

What does under-stoichiometric or stoichiometric mean?

When people talk about oxides like $\ce{SiO2}$ or $\ce{Al2O3}$, they use expressions like stoichiometric or under-stoichiometric. I understand that this refers to the relative composition of materials,...
0
votes
1answer
188 views

Can high-tin bronze be made sharper than low-tin bronze?

I am not sure how sharpness is measured, but I do know that certain materials can be designated sharper than others, for example obsidian is said to be the sharpest material: The prismatic glass ...
2
votes
2answers
3k views

Writing the net reaction for reaction of sodium hypochlorite with hydrochloric acid and potassium bromide

I am currently taking a general chemistry course and during a lab they had us do the following procedure: Place $\pu{2 mL}$ of $5\%$ $ \ce{NaClO} $ solution in a test tube. Add $10$ drops of ...
2
votes
1answer
2k views

Alternatives to Congo Red?

I require Congo red indicator for an experiment I wish to perform involving dipping a cellulose sponge into an acid and a base. I first want to dye the cellulose sponge with Congo red, and observe ...
0
votes
3answers
335 views

How does caesium’s density change with temperature?

According to Wikipedia caesium’s density is $1.90\ \mathrm{g/cm^3}$ at $\Theta =20\ \mathrm{^\circ C}$. How does this change when $T$ changes? E.g. will it expand when melting?
1
vote
1answer
53 views

Can I deduct heteronuclear van der waals parameters from homonuclear parameters in a forcefield?

I got a forcefield (OPLS-AA in this case) that lists lennard-jones parameters for all homonuclear van der waals interactions. Is there a way to deduct the heteronuclear vdw-interaction parameters from ...
3
votes
2answers
1k views

Recreational drugs by half life

I am interested in the Biological Half Life of substances. In the previous wikipedia link, I've already found the half lives of common pharmaceutical products. I can't seem to find similar data for ...
2
votes
1answer
1k views

Explanation of the Selection rule in light of IR spectroscopy

I am in mathematics, but I am writing a paper on molecular vibrations (because you can use representation theory to handle this). I want to prove the selection-rule, but I also have to give a ...
12
votes
2answers
755 views

Can we process waste just by decomposing it to homogenous mass and extracting the elements from it?

I. e., what if we just burn trash completely or dissolve it in acid, get the resulting paste and extract pure chemical elements out of it by applying some physics and/or chemistry to it until no more ...
2
votes
0answers
237 views

How would you change the chirality of a compound such that (S,R) becomes (S,S)? [closed]

How would you change the chirality of a compound such that (S,R) becomes (S,S)? That is how would you synthesise a compound from its diastereomer?
2
votes
0answers
2k views

How, chemically, would you remove protruding phenyl groups?

How, chemically, would you remove protruding phenyl groups? I mean for instance in the molecule phenethylamine there's a phenyl group sticking out (or protruding) how would you go about removing this ...
6
votes
1answer
12k views

Normal Spinel and Inverse Spinel

According to my notes, octahedral site stabilization energy (OSSE), sterical effects and electronic effects in stability create a confusion in this theory. However, we are able to solve this problem ...
3
votes
2answers
2k views

Predicting molecular geometry from a formula

Can someone explain the following types of molecules and predict their structure and shape? It will help my understanding if you could provide an example. ...
2
votes
3answers
17k views

At equilibrium, the mass of reactants and products are equal. Does that mean the reaction stops?

This one is troubling me, and I even got it wrong in my exam: at equilibrium the mass of reactants and products are equal, does that mean the reaction stops? Please explain this one.
0
votes
1answer
13k views

How do you find the pH of a solution with a known pKa and Molarity?

How do you find the pH of a solution with a known pKa and Molarity?
-2
votes
1answer
22k views

How to determine the order of boiling points and solubilities for (chloro-)alkanes, ethers, aldehydes, and alcohols?

How to determine the order of boiling points and solubilities for (chloro-)alkanes, ethers, aldehydes, and alcohols? What rules can be applied to make these choices? Take for example the following ...
5
votes
2answers
8k views

Presumptive test for modafinil?

Given a sample that is probably modafinil plus common fillers, but could be fake, what reagent tests would best determine whether it contains modafinil? Assume a known-good sample for comparison. (...
7
votes
1answer
26k views

How does sodium bicarbonate act as a deodorizing agent?

I was reading this other question on the site: Deodorizing using baking powder instead of baking soda. Apparently, baking soda is used quite often as a cleaning and deodorizing agent. From what I ...
0
votes
2answers
7k views

How to find the molecular weight of a given gas based on its density?

The density of a gas $\ce{X}$ is $10$ times that of hydrogen. In that case, what is the molecular weight of gas $\ce{X}$? Well what I've done up to now is this: The molecular mass of hydrogen is $M(\...
4
votes
1answer
166 views

In acidic solution, what does ClO₃⁻ reduce into?

In acidic solution, what does $\ce{ClO3-}$ reduce into and, most importantly, why? It's $$\ce{6e- +ClO_{3}^- +6H^+ -> Cl^- + 3 H_2O}.$$ Now, with the gift of foresight, why was the equation for ...
2
votes
1answer
612 views

Solid hydrophilic transparant materials that don't dissolve in water

I am looking for hydrophilic transparant materials which are solid at room temperature and that don't dissolve in water. I need these for an experiment in which I condense droplets on a plate made out ...
4
votes
5answers
269 views

Is it possible for an acid and base to react to form an even stronger base or acid?

Is there a combination of an acid and a base that when mixed results in a solution that is more basic or more acidic than the initial base or acid, respectively? If so, do such combinations have a ...
1
vote
2answers
4k views

What defines the specific enthalpy of atomization? [duplicate]

1 mol of $\ce{F2}$ is turned into $\ce{2F}$ (atoms). Is this the specific enthalpy of atomization, or two times that?
4
votes
1answer
47k views

Deodorizing using baking powder instead of baking soda

I am an engineer and I understand the difference between baking power and baking soda as baking powder is baking soda (alkali) with tartaric acid (acidic) and an inert starch (why? Is this a catalyst ...
6
votes
2answers
659 views

Measuring Thermodynamic Stability

We can predict whether a reaction can occur spontaneously by calculating the change in Gibbs' free energy. I was just wondering whether there is any general measure of the thermodynamic stability of ...
2
votes
2answers
23k views

Does SiO₂ have polar covalent bonds or coordinate covalent bonds?

First off, I know $\ce{SiO2}$ is a network solid. I am looking at its intramolecular forces between the $\ce{Si}$ and the $\ce{O}$ molecule. On the one hand, it seems to me that this should be a polar ...
2
votes
2answers
2k views

Hot and cold air interaction in a sealed environment

What would happen if air heated to 1200 degree's Fahrenheit in a sealed environment was injected with colder air? No specific pressure defined yet just a general idea of potential interaction between ...
18
votes
3answers
16k views

Why is heating increasing the solubility of sodium hydroxide?

\begin{align} \ce{NaOH &-> Na+ + OH-} & \Delta H^\circ &= \pu{-44.51 kJ/mol} \end{align} The dissolution of sodium hydroxide in water is an exothermic process, and so, according to Le ...
8
votes
1answer
44k views

Molecular orbital theory & predicting the stability of a molecule?

A question in my general chemistry textbook gives me a list of formulas for molecules and ions. It then asks me to determine, using molecular orbital theory, whether or not each would exist in a ...
7
votes
2answers
296 views

How was the quantum three-body problem solved?

What method was used to solve the quantum three-body problem? I heard it was solved and was not sure about the status of the problem.
7
votes
2answers
38k views

Strength of intramolecular vs intermolecular hydrogen bonds

Why are intramolecular hydrogen bonds weaker than intermolecular hydrogen bonds?
-4
votes
2answers
4k views

Carbon atoms in triple bonds [closed]

I was trying to know what is the probability for the carbon atoms to rotate .I know that in single bond it is 0 % and I think it is 100 % in double bond but how about the triple bond ?
8
votes
1answer
6k views

Why is it hard to reduce titanium dioxide?

Titanium is expensive, although it is not rare and titanium dioxide is a ubiquitous component, it's part of such mundane articles as toothpaste, paper or plastics. The reason for that is that the ...
1
vote
1answer
3k views

How do I calculate the number of moles in the mixture?

5.5 g of a mixture of $\ce{FeSO4.7H2O}$ and $\ce{Fe2(SO4)3.9H2O}$ requires $5.4 \:\mathrm{mL}$ of $0.1 \:\mathrm{N}$ $\ce{KMnO4}$ solution for complete oxidation. Calculate the number of moles of ...
12
votes
1answer
52k views

What is the mechanism for oxidation of ketones by the Popoff's rule?

Ketones are relatively much harder to oxidise, but they do undergo oxidation reactions at extreme temperatures. Our teacher also told us about Popoff's rule which states that, on oxidation of ...
2
votes
1answer
118 views

Overlapping oxygens in crystal structure — what's going on?

This is a screenshot of a portion of a metal organic framework (MOF). These are two oxygens of two NMP solvent molecules. What I am wondering is why they are so close and overlapping like this. I ...
10
votes
2answers
36k views

Is astatine a non-metal or a metalloid?

Is astatine a non-metal or a metalloid? A metalloid is an element which exhibits some of the properties of a metal as well as those of a non metal.
5
votes
1answer
197 views

$K_{eq} $ vs $K_c$

I was wondering if there was a difference between $K_{eq}$ and $K_c$. I think they both refer to the Equilibrium Constant. If I'm wrong, could you please tell me the difference between the two? Thanks!...
4
votes
2answers
270 views

Will borosilicate glass absorb 808nm laser light?

Will borosilicate glass absorb 808nm laser light? If it instead refracts, then what is the refractive index? Also, will borosilicate reflect lower frequencies of light like those used in non contact ...
0
votes
1answer
161 views

Reconciling multiple inorganic properties for the purposes of learning these elements

How can I reconcile all of the chemical properties, physical properties and peculiar behaviour of metals in inorganic chemistry for the purposes of studying these systematically? It is very hard to ...
2
votes
1answer
3k views

Boiling and Melting point of Lithium (or any other element that does not occure in free state)

The melting and boiling point of Lithium as compared to other members of the Alkali group metals is high. But, Lithium does not occur in the free state. So, what does it mean that it has high ...
54
votes
3answers
776k views

How do I figure out the hybridization of a particular atom in a molecule?

I'm learning how to apply the VSEPR theory to Lewis structures and in my homework, I'm being asked to provide the hybridization of the central atom in each Lewis structure I've drawn. I've drawn out ...
1
vote
2answers
3k views

Chemical formula of ethanol and other carbon compounds

Should chemical formula of ethanol be written as $\ce{CH3CH2OH}$ or $\ce{C2H5OH}$? And whats the logic behind it? I have seen the former being used more often, so why is ethane represented by $\ce{...
9
votes
3answers
940 views

Why is this atom sp² hybridised? [duplicate]

I'm doing exercises on hybridisation, and I was given this molecule: I'm wondering about this (electron deficient) oxygen atom. My intuition says it should be ${sp^2}$ like the answer says, but ...

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