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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21 views

Does Photoelectric effect occur in a micro-oven while heating food? [on hold]

Does the photoelectric effect occur while heating food on a metal plate in a microwave oven? If not, then why doesn't it occur?
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18 views

Chemistry(redox reactions) [on hold]

How does the H2O2 form to H2O and O2, My problem is how the Oxygen gets positive and negative oxidation numbers? oxygen is a non metal. So how it gets negative oxidation number?
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2answers
33 views

Calculating Enthalpy Changes at Different Temperatures

To calculate $\Delta H$, the change in ethalpy at $100\ \mathrm{^\circ C}$ for the reaction below, one needs what addition information? $$\ce{N2(g) + 3H2(g) -> 2NH3(g)}$$ $\Delta H^\circ = -92.0\ ...
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2answers
409 views

Why is there a sudden drop in the concentration of ammonia in this graph?

So initially they are mixed with the mole ratio of $\ce{H2}$ and $\ce{N2}$ being 3:1 respectively. It seems as the reaction proceeds, both these quantities decrease and the quantity of ammonia ...
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1answer
51 views

Any chemicals combines readily oxygen?

I am designing an industrial process which can remove oxygen from air. This chemical should combine readily with oxygen in the presence of heat. In particular, I am looking for a chemical with the ...
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0answers
12 views

Hydrogen visible transition [duplicate]

Why is there only four visible transitions in the hydrogen atom? What causes the hydrogen atom to only have the four visible transitions?
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41 views

Hydrogen visible transitions

When dealing with electrons and the electromagnetic spectrum, why are there only four visible transitions in the hydrogen atom?
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1answer
54 views

Just how quantized are energy levels?

One thing which has bothered me for a while about the idea of quantized energy levels is that it's clear just how quantized they are. Let me give an example. If I was looking the energy some ...
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0answers
29 views

Why Bond order of CO+ is 3.5?

While studying I found that the bond order of CO+ is given 3.5 ? But it should be 2.5 . Also on searching on Google I found the following answer that is on stack exchange but Its says about the bond ...
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25 views

What closure relations can we use in molecular modelling?

Following my question here about the BBGKY hierarchy I was wondering does anyone have any experience in using the method outlined. In particular how would I take an equation off the page and for some ...
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0answers
14 views

Reading enthalpy of mixing graph

I'm struggling to interpret enthalpy of mixing data. Given this plot, from this paper, say I want to calculate the heat released from mixing 0.29 mol of 7.7% ethanol with 0.71 mol of 28.7% ethanol to ...
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2answers
52 views

Spontaneity of reversible reactions

If a reaction has positive $\Delta G$ then reverse reaction has negative $\Delta G$. How can both occur simultaneously, e.g., in a reversible reaction such as dimerisation of $\ce{NO2}$ to form ...
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2answers
223 views

Why is CO practically nonpolar?

This question was in my book. According to me CO should be polar as it should have a dipole moment. But I found that the $\sigma$-electron drift from C to O is almost nullified by the $\pi$-electron ...
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23 views

What should be the shape of SF2Cl2?

In one question I found that shape of SF2Cl2 was given as trigonal bipyramidal . But its structure is trigonal bipyramidal and shape should be trigonal pyramidal as one lone pair is present which is ...
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0answers
14 views

How do I prepare the following solution I found in a research paper?(Details given below) [closed]

So I came across this research paper to synthesize nanoparticles and I want to replicate the experiment they did.Here is their experimental procedure(in their words) : 1.FeCl2·4H2O and FeCl3·6H2O ...
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1answer
24 views

Calculation of the lowest energy conformation with a webbased solution or freeware

I like to draw a molecule in different conformations in a) website or b) freeware and Calculate its relative energy difference (for example to the lowest global energy conformation) Display the ...
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0answers
7 views

With respect to colloid chemistry explain why sky is red in the morning and evening and blue at noon [closed]

Can colloid chemistry explain the phenomena behind why sky is red in the morning and evening but blue around noon?
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2answers
48 views

How much does a light heat the air around it?

My dad told me to turn off the lights when I'm not using them because it will keep the house cooler. I don't think he is correct that a light can heat up the room. How much of a difference in the ...
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3answers
65 views

How do things “glow in the dark”?

The only explanation that I can come up with for what makes things "glow in the dark" is that there is probably a chemical reaction slowly releasing the light that was previously absorbed. Am I ...
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0answers
44 views

Which graph shows Chemical Equilibrium?

So my teacher started the explanation of Chemical Equilibrium saying.. The concentration does not change with time. And, gave us certain graphs asking which ones show chemical equilibrium. I cannot ...
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0answers
15 views

Removing harmful gases from automobile exhaust using electrostatic precipitation

If I attach an electrostatic precipitator to a car's exhaust - and also make the smoke pass through an area containing $\ce{NaOH}$ in order to absorb sulfur dioxide - does that mean that the smoke ...
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1answer
22 views

Why is the acoustic absorption coefficient of hexane in air less than air?

Why is the acoustic absorption coefficient of hexane in air less than air? A 120 kHz pulse train exhibits a larger amplitude after traveling in a hexane/air mix than in pure air. My hypothesis is ...
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0answers
26 views

Glycine nucleation simulations

I am trying to run nucleation simulations of glycine in water. To generate a supersaturated solution, a solution that will crystallize, I need to know the solubility. Luckily for me, this data exists. ...
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1answer
39 views

In which of the compounds ONO bond angle is maximum?

Which has maximum $\ce{ONO}$ angle.? $\ce{NO3-}$ $\ce{NO2+}$ $\ce{NO2-}$ $\ce{NO2}$ According to me $\ce{NO2+}$ should have max angle because the structure is linear but in answer it is given ...
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1answer
23 views

Which element should be placed in axial position bulky one or the smaller one?

In one question for finding P(CH3 )2H3 structure ? Which one should be placed in axial position ? I think CH3 should be axial position to minimise repulsion.
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2answers
1k views

Why don't gases escape Earth's atmosphere?

Some gases are lighter than others and rise. Why don't they continue going up, leave the atmosphere, and then enter outer space?
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1answer
37 views

Equilibrium of liquid-vapour at boiling point; which is equal, kinetic or potential energy?

A liquid is in equilibrium with its vapor at boiling point. On average do the molecules in the two phases have equal potential energy or equal kinetic energy? Why? I can't really decide ...
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1answer
42 views

Justification for Freezing Point Depression & Boiling Point Elevation in Solutions?

I was wondering if the following justification for freezing point depression and boiling point elevation are conceptually correct. The reason why I ask this question is because I have been self ...
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1answer
38 views

Uniform circular motion of electrons?

Can we use the uniform circular motion formulae to calculate the velocity of an electron along with the formula of radius of nth Bohr orbit? And using that can we calculate the kinetic energy of an ...
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1answer
43 views

What is Oxidation Number?

How it can be calculated? How the questions is asked based on oxidation number? Please give the answer in a very easily understandable way. Thanks....
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0answers
24 views

Relating 'temperature' difference to 'vapour pressure'

I am aware of the fact that with the increase in temperature, the number of molecules with more kinetic energy increases and thus, the vapour pressure increases. When we increase the temperature ...
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0answers
22 views

Dielectric Constant of Gold Oxide

I've found the dielectric constant of Aluminum oxide and such, but what's the dielectric constant of Gold Oxide. I haven't found it on the internet so far.
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1answer
126 views

Physical intuition behind negative values for wave function?

So a positive and a positive wave function create a bonding orbital where the probability of finding an electron is summed while a positive and a negative create an anti-bonding orbital with a lower ...
3
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1answer
76 views

How long does it take to change states of matter?

I'm interested to know how long it takes to change states of matter and why it takes the time that it does. For example, what is the very quickest that we could freeze a packet of chicken breasts? ...
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1answer
46 views

Does a gold detector exist?

I see many sites that claim to sell working gold detectors but I am not convinced that they work. Also, does a metal detector detect gold?
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1answer
31 views

Derivative of Gibbs Energy wrt Temperature at constant Internal Energy

I came across with the following solution from Sandler's book: $$\begin{eqnarray}\left( \frac{\partial G}{\partial T} \right)_U &=& \frac{\partial (G,U)}{\partial (T,U)} \\ &=& ...
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1answer
56 views

Why some materials are transparent, but other ones aren't?

We have two materials; say glass and wood. Light passes through glass but it doesn't pass through wood. Is it caused by atoms and molecules arranged in glass and wood such that they interact ...
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1answer
430 views

Why are the plastic balls used to reduce evaporation in this reservoir black instead of white?

Plastic balls have been added to a reservoir in drought stricken California in order to reduce evaporation. Link to news story here Why are the balls colored black instead of white? I would think ...
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0answers
14 views

Is there a specific chemical property or concept that explains/predicts the triboelectric series?

Is there a chemical property (perhaps electron affinity?) that can be used to predict where a substance would fall in a triboelectric series such as this one? Or would the cause of the charge ...
6
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2answers
88 views

Is there a soluble salt, or compound that when dissolved in water results in a solution with density less than pure water?

Generally water soluble salts tend to 'fit between' the molecules of water such that the volume of the resulting solution does not increase much relative to the volume and added mass of the salt. So ...
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1answer
53 views

Relationship between dipole moment of a molecule and electronegativities of constituent atoms

I want to know if I can calculate the dipole moment of a molecule given the electronegativity values for the atoms comprising it. I think that dipole moments determine the polarity of molecules, so ...
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1answer
29 views

Properties of plasmas

In chemistry one can recognize that the four states of matter are solid, liquid, gas and plasma. The first is rigid, and has a definite shape and volume. The second doesn't have a shape, and assumes ...
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48 views

Density of non-ideal vapor mixtures

I'm looking for a reasonably accurate density of a mixture of two gases that act quite unlike ideal gases (generally steam and water-miscible solvents). We can get a first order estimate by taking a ...
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0answers
32 views

Container to supercool water

The internet is full of videos like this showing water bottles for drinking used to supercool water. These bottles, not unexpectedly, appear a bit finicky, since they have lots of edges to serve as ...
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0answers
23 views

Why does a mixture of siloxene and cerium(IV) sulfate luminesce?

Not long ago, I did an experiment where siloxene and cerium(IV) sulphate were mixed together. The mixture produced an orange-yellow glow. Why does it glow? What is it about the two chemicals in ...
5
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1answer
52 views

Does the Maxwell-Boltzmann distribution apply to gases only?

The Maxwell-Boltzmann distribution can be used to determine the fraction of particles with sufficient energy to react. I know that the curve applies to gaseous reactants and would like to know whether ...
16
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3answers
1k views

How does oil on the surface of water prevent rust?

I distinctly remember a side-by-side comparison from a book where there are two nails submerged in water, in two beakers: one nail had a layer of oil on top of the water, and that nail didn't rust; ...
2
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1answer
30 views

Relationship between vapour pressure and saturated vapour pressure

I need clarity on saturated vapour pressure in a closed system at equilibrium. How does saturated vapour pressure relate to vapour pressure?
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1answer
17 views

Do ion-exchange resins soften water through a kinetic equilibrium process?

I searched a lot for this and couldn't find any answers. Is water softening a purely ratio-based equilibrium process, ie, more $\ce{Na+}$ cations on resin than there are $\ce{Ca^2+}$ cations in the ...
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0answers
23 views

Quenching rates in nucleation MD simulations

I am trying to perform nucleation simulations with molecular dynamics. To prepare the metastable fluid, I am equilibrating at temperatures about 30 K above the melting temperature, and then ...