The study of chemical systems using the laws and concepts of physics. This usually requires the techniques of thermodynamics, statistical mechanics and quantum mechanics.

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5 views

water refinary with electrical field

can we refine sea water by a high electrical field if we put a narrow of water on a surface in a high electrical field that salts with positive charge go to one side an salts with negative charge go ...
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0answers
20 views

Find coordination number [on hold]

If we are given the radius of Mg+2 and O2- as 0.65 A & 1.40A respectively . Then how can we calculate the coordination number of cation in the crystals of MgO . Can anyone tell me concept behind ...
21
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3answers
3k views

Does any known substance ignite on cooling?

As the title says, I'm interested to know if there's any substance or combination of substances which ignites (or even increases its chance of spontaneous ignition) when cooled. I've never heard of ...
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0answers
13 views

it's about the finding the compound [on hold]

which compound is covelnt sp3 hibrid orbital contain structure of ammonia types of bond present in cuso4 . 5H2O are only sulphuric acid molecule contains hodrogen chloride molecule contains The ...
2
votes
1answer
318 views

Which is hardest: iron, brass or bone?

I was hopping around random wikipedia articles when I came across the article for the Behemoth. In the description for the beast it says: His bones are as strong pieces of brass; his bones are ...
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1answer
34 views

What is the position of hydrogen in the periodic table? [duplicate]

Hydrogen is not in the first group as it was before and it is now placed above the periodic table? So why is it still categorized as a metal in some books?
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1answer
15 views

chemical reactions and energy [on hold]

Ammonia is an important ingredient in many fertilizers. The main process by which ammonia is made is the Haber process. In this process, nitrogen gas and hydrogen gas are reacted to form ammonia at ...
4
votes
4answers
131 views

how to mathematically predict reaction results

I've been trying to computationally achieve the following (I have no lab, I'm 14 years old, and I want to make a Minecraft mod to teach real Chemistry): I want to mathematically predict the range ...
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1answer
46 views

Is enthalpy of activation the same as activation energy? Is there a purely mathematical way to find that value?

I asked about the effect of pressure on a reaction, and since then I learned a lot more. One of the things I learned was the Eyring equation: $$\kappa = \frac{\kappa_B T}{h} e^\frac{\Delta^\ddagger S°...
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1answer
41 views

How much volume of oxygen will be required for complete combustion of 40 ml of acetylene and how much volume of CO2 and H2O will be formed?

How much volume of oxygen will be required for complete combustion of 40 ml of acetylene and how much volume of $\ce{CO2}$ and $\ce{H2O}$ will be formed? After balancing the left-hand side produces 5 ...
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3answers
47 views

Whether copper can combine with oxygen in equal proportion?

Copper sulphide contains 66.6% copper and sulphur trioxide contains 40% sulphur. According to law of reciprocal proportions copper is 80% in copper oxide. The calculation: In the first, for 33.4% ...
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0answers
16 views

If the workfunction of a metal is 5.2 eV, the corresponding threshold wavelength is? [closed]

Answer choices: a. 527 nm b. 237 nm c. 464 nm d. 344 nm e. 437 nm
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1answer
35 views

Symmetries of the v=0 and v=1 quantum harmonic oscillator wave functions and those of the Cartesian Coordinates (References)

I'm busy with a writing project for my third year Chemistry course and in the project one of the things we need to consider and answer is the symmetries of the v=0 and v=1 quantum harmonic oscillator ...
0
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1answer
41 views

What will be the equivalent weight? [closed]

This question is simple but I posted this because I am unable to do all sums similar to this. My answer is not matching with the one in my book. Please help. The question is: $4215~\mathrm g$ of ...
3
votes
1answer
56 views

Boiling Point lower than Melting Point?

Under the Wikipedia entry for Metaldehyde is listed a Melting Point of 246 C and a Boiling point of 110 C (actually, it says it sublimes). How can a Boiling point be lower than the Melting Point? ...
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0answers
12 views

Tha Pka1,Pka2,Pka3 values for H3PO4 are 2.15,7.20,12.15 respectively.When 50 ml of 0.10M Na2HPO4 are mixed with 50 ml [closed]

Tha Pka1,Pka2,Pka3 values for H3PO4 are 2.15,7.20,12.15 respectively.When 50 ml of 0.10M Na2HPO4 are mixed with 50 ml of 0.10 M Na3PO4 ,What is the ph of the resulting solution?
-1
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0answers
17 views

Thermodynamic process & cycle [closed]

an ideal gas has a volume of 0.3m3 at 350k and 4 bar was compressed in adiabatical process to 12 bar. Later on the gas was cooled in isochornic and further the gas was expanded in isothermal so as to ...
2
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2answers
44 views

Over potential -what and why ?

Value of standard electrode potential for the oxidation of Cl– ions is more positive than that of water, even then in the electrolysis of aqueous sodium chloride, why is Cl– oxidised at anode instead ...
2
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1answer
32 views

High Water pressure [closed]

Say I had a laser drill that could cut a 2 km circle. I start it up in the deepest part of the ocean. I would then be cutting a 2 km circle straight for the earth core but just before I hit the liquid ...
0
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1answer
36 views

Copper metal with silver ion

New to chemistry. In my book it states that 2AgNO3(aq) +Cu -->Cu(NO3-)2(aq) +2Ag(s). In addition to the formula it depicts an image of the reaction. It depicts an image shown here: https://imgur.com/...
2
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2answers
133 views

Generation of singlet oxygen by irradiation [on hold]

What is the mechanism involved in the generation of singlet oxygen when ground state triplet oxygen is irradiated in the presence of rose bengal?
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1answer
20 views

Given a theoretical combustion engine, how can I calculate the output of this engine depending on the fuel it uses?

I'm writing a Minecraft mod (for those who don't know, it's sort of like a smaller "program" that loads into the Minecraft game and expands it, by adding other things to it). My question is: consider ...
3
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2answers
39 views

Understanding what is happening when something is dissovled

Let's start with a saturated solution of NaCl in water. At this point, any further addition of NaCl at the same T and P would not dissolve. However, if I then add another fully soluble salt (say AgNO3)...
4
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2answers
98 views

Any example of colloidal solution where liquid Helium is solvent?

I would like to see any information, if it exists, about colloidal solutions where Helium is "solvent". Background of that question is, I'm wondering giving surface energy effects, how potentially ...
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1answer
64 views

Heisenberg's uncertainty principle [closed]

Can anyone explain Heisenberg's uncertainty principle and it's derivation. Im a 12th standard student.Please make it simple enough for me to understand.
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1answer
33 views

3 component (ternary) system in equilibrium

If the components of a system were Cl2, Br2, and I2, how could I describe this system under equilibrium conditions when the number of phases is at a maximum? If there are 3 components, using the ...
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0answers
15 views

Why mole fraction equilibrium constant depend on pressure and volume?

The ratio of rate constants for forward and backward reaction gives us the equilibrium constant (say kc). 1.Rate constants depend on temperature and catalyst (Kinetics). 2.Their ratio i.e ...
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1answer
48 views

Does the rate function of an elementary reaction depend on the other steps of the mechanism?

A question came to my mind. Is the rate function of an elementary reaction influenced by the other steps of the mechanism? I wonder whether the shape (not the values) of the function $r(c)$ belonging ...
2
votes
1answer
53 views

Why does CO2 diffuse through a butyl rubber membrane more readily than air?

I am a cyclist, and not a chemist. When I or my cycling buddies get a flat tire out on the road, after removing the offending sharp object (if any) remaining in the tire, we will typically replace the ...
2
votes
0answers
32 views

What will be the coordination number in Fe(0)?

Fe(0) has its electronic configuration 3d6 4s2 in the ground state. In this case multiplicity will be either 1 or 3 during excitation. If multiplicity is 1, the vacant excited orbitals are dsp3. So, ...
1
vote
1answer
27 views

How do proton exchange membrane electrolysers work?

I've seen lots of videos, animations, and a few Wikipedia pages, but I'm still trying to figure out a few things. Is an electrolyte needed to make the water conductive like an alkaline electrolyser? ...
0
votes
1answer
45 views

Does Oxygen exhibit +1/2 oxidation state?

Theoretically it is said that the compound can show oxidation states in the interval: [n,n-8] where n=valency electrons. Is there any compound in which oxygen ...
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1answer
19 views

The Thomson wheel experiment

JJ Thomson did an experiment with discharge tube using hydrogen gas. Later it was found that anode rays and Cathode rays both exist at the same time.. Cathode rays move opposite to anode rays. My ...
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3answers
64 views

Why is the stoichiometric coefficient in the denominator in the rate expression?

For the reaction: $$\ce{2A + B → C}$$ The rate expression is given as: $$\ce{-1/2 * Δ [A]/Δt}$$ = $$\ce{-1 * Δ [B]/Δt}$$ = $$\ce{Δ [C]/Δt}$$ I can't get my head around why it is $$\ce{-1/2 * Δ ...
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vote
2answers
72 views

How do EM waves cause molecules to rotate, move, and cause electrons to move up energy levels?

Atoms can absorb electromagnetic waves to cause electrons to jump up energy levels, when electrons go down energy levels they release a photon. But how do EM waves cause atoms to rotate, and vibrate?
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2answers
49 views

Why is $^3P_1$ an atomic term symbol for carbon?

I'm using these rules, $^{2S+1}L_J$ with $J=L+S$ and it seems to imply that $^3P_1$ means $S=1$, $L=1$, and $J=1$ but clearly $1+1 \ne 1$ so according to me this shouldn't be an atomic term symbol but ...
2
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2answers
41 views

How do non-sublimable solids exist in equilibrium with vapour

All substances exist in equilibrium with vapour, something I learned from Jan's comment. But my question how do that happen with solids that are non sublimable, like ice, piece of iron and a piece of ...
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2answers
40 views

What are the order of the reaction under the following conditions?

The experimental rate of a reaction $$\ce{A + 2B -> C + D}$$ $$\frac{\mathrm dx}{\mathrm dt} = K[\ce{A}][\ce{B}]^2$$ Calculate the order of the reaction when (i) $[\ce{A}]\gg[\ce{...
2
votes
3answers
87 views

Why is the boiling point of a solution higher than that of a pure solvent? [duplicate]

My reasoning When non-volatile solid solute is added to a solvent some of the liquid solvent molecules are replaced by solute molecules at the surface.The lesser the number of solvent molecules at ...
-5
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0answers
36 views

Find bond lengths from moments of inertia [on hold]

How do I find $r$ in a triatomic (asymmetric molecule) if I know $I_\mathrm a$, $I_\mathrm b$, and $I_\mathrm c$? So I can calculate $r_\mathrm a$, $r_\mathrm b$, and $r_\mathrm c$ using rotational ...
0
votes
1answer
36 views

Effect of an inert gas on steam vapor pressure at equilibrium

Suppose we have a closed container with mobile walls, so it will change its volume in order to equal the external pressure(constant) to the internal pressure. This container has inside it a liquid ...
3
votes
2answers
282 views

Are there different types of symmetry? [duplicate]

What factor does the symmetry of a molecule play? For example, I know water is asymmetric so does this therefore make water polar (I know in fact that is is)? It may sound ignorant due to my lack of ...
3
votes
1answer
57 views

Find moment of inertia - SO2 axis (asymmetric?)

Problem asks to find the moment of inertia for 2 axes of $\ce{SO2}$. The rotational constants are given in MHz. The answer is required to be $10^{-46}\rm~ kg\cdot m^2$, 7 digit accuracy. I used $$I =...
4
votes
1answer
86 views

How to explain Born repulsion between ions in gas phase?

In simple terms, the collision of two atoms $\ce{A}$ and $\ce{B}$ will result in ions $\ce{A^+}$ and $\ce{B^-}$ if $$I_a(\ce{A})+E_a(\ce{A})<I_a(\ce{B})+E_a(\ce{B})$$ where $I_a$ and $E_a$ are the ...
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0answers
35 views

Spectator mode; what is

I'm reading a paper, found a line: "The other modes have relatively small contributions for the displacements of the heavy atoms and can be considered as spectator modes for the internal conversion". ...
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0answers
23 views

what is the amout of pressure that is needed to make alcohol evaporate/boil at room temperaturecelsius or around 20-25°C

I need to make alcohol evaporate from a solution without bringing it to a high temperature. I do know that is achieved by putting the solution under pressure but what i don't know, and cant find ...
5
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2answers
108 views

Is glass an amorphous solid or supercooled liquid?

I have been informed that glass is a super-cooled liquid and is also considered to be an amorphous solid. Can it be both and, if not, what category does it fall into?
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0answers
44 views

What is de-Broglie's hypothesis?

Was the relation between wavelength and momentum derived or is it just an empirical relation ?
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1answer
21 views

What makes DNA/Protein in a gel run in straight lines?

In a gel electrophoresis, let's assume an SDS-PAGE, I understand that the sample is loaded on a cuboidal well and the electric field is straight downward. It is easy to assume that the sample is going ...
0
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0answers
14 views

Why are these materials like gallium arsenide, gallium phosphide, aluminium gallium arsenide etc used in Light Emitting diodes?

Indium gallium nitride (InGaN): blue, green and ultraviolet high-brightness LEDs Aluminum gallium indium phosphide (AlGaInP): yellow, orange and red high-brightness LEDs Aluminum gallium arsenide (...