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Questions tagged [physical-chemistry]

Study of macroscopic and microscopic phenomena in chemical systems in terms of physical laws and concepts [thermodynamics, statistical mechanics, kinetic theory, quantum mechanics...].

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How do you work out the de broglie wavelength of $C_{10}H_{10}Br_2$? [on hold]

I've got the molecule given in the title, it's at 800K and I need to work out the de broglie wavelength in order to set up a (theoretical) double slit experiment. I've used the equation $E = \frac ...
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20 views

What are the specific heats of Dysprosium in its gas phase?

What are the specific heats of Dysprosium in its gas phase? The handbook of chemistry and physics [1], is a single volume of 1500 pages containing all the information an experimentalist would need ...
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1answer
19 views

Hydrogen oxygen fuel cells

In hydrogen - oxygen fuel cell, the electrode used is carbon electrode.Hydrogen is passed through through the anode compartment where it is oxidised. Oxygen is passed through the cathode compartment ...
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2answers
27 views

How to determine at which temperature does iron in stainless steel undergoes spontaneous oxidation?

It is my understanding that iron oxidation in stainless steel is prevented by adding chromium, which creates chromium oxides at the surface that shield the bulk of the material from further oxidation. ...
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42 views

Can gamma radiation, at energy range 1-10 MeV, induce chemical decomposition of sodium bicarbonate at dosages of 25 kGy? [closed]

Is gamma radiation, at energy range 1-10 MeV, induce chemical decomposition of sodium bicarbonate, into water, carbon dioxide, etc., at dosages of 25kGy?
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How to determine symmetry of the system from the term symbol?

I'm studying term symbols. I can derive them mechanically from the electron configuration using the complete table of microstates. Let's consider a typical example - an atomic carbon with the ...
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2answers
89 views

Does chemical bonding decrease the entropy of the universe?

I have read in many credible texts ( including "a brief history of time" ) that nature always increases entropy, that is, the entropy in the universe increases. But I learnt that atoms and molecules ...
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19 views

Tight binding model and LCAO

What is the qualitative difference between the tight binding model and Linear Combination of Atomic Orbitals(LCAO) that is used in Chemistry? I have read that LCAO is a type of tight binding model. ...
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1answer
14 views

Why enthalpy variation is not zero at a constant pressure physical state transformation?

I was checking Castellan's Physical Chemistry. So, there's a passage that states: Consider a liquid in equilibrium with its vapor under a pressure of 1 atm. The temperature is the equilibrium ...
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Rate equation of a radical [migrated]

Could anyone help me with this question. This question is from the book Introduction to Combustion: Concepts and Applications by Stephen R. Turns. My answer to the second part is $$\frac{d[OH]}{dt}...
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2answers
72 views

How exactly does quantum mechanics play a role in our day to day life?

From my understanding, quantum mechanics applies mainly to small microscopic particles. When it comes to macroscopic objects, the wave functions collapse and the quantum mechanical properties are lost....
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179 views

Why does the humidifier “really” make a stove's flame orange? [duplicate]

I answered this question- Why does the humidifier make a stove's flame orange? and earned 300 rep points for it as an "accepted" answer, but serious doubts have arisen about its correctness. ...
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How to find all the possible spectral term for an atom configuration using LS coupling in the case of two unfilled subshells?

I'm not sure how to find all the possible spectral terms for an atom configuration where there are two shells not completely filled or empty. Here the LS coupling is described for 2 electrons in 2 ...
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6answers
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Why does the humidifier make a stove's flame orange?

Just like this guy's, the color of my stove's flames were affected by the humidifier as well. Why does this happen? Is it a good thing or a bad thing ?
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1answer
25 views

Growth of bubbles in supersaturated liquid

I have read the following section which I don't fully understand (I have no technical background). It's from this article which is about the formation of bubbles of CO2 in soda drinks. When a ...
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0answers
10 views

Dynamic rolled-supercapacitor & Lorentz force & Induction?

I've been designing certain components that would have a supercapacitor attached to a movable (rotation/linear) element. The element is conductive and carries the current from(discharging state) the ...
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3answers
46 views

Redirecting light using light

I was wondering if it were possible to have some chemical that would change it's state for some duration when hit by a beam of some frequency of light, such that it would change from transparent to ...
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3answers
39 views

How might cosmic inflation affect chemistry and nuclear interactions?

How might cosmic inflation affect chemistry and nuclear interactions? Hypothetically, if I am alone (wearing a spacesuit) in a large but empty universe, and the inflation of this universe is such ...
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In what cases (precisely) are Hund's rules valid?

I can't find on any good source (such as a textbook) a precise specification about the cases when Hund's rules (especially Hund's third rule) for an electronic configuration of atom are valid (the ...
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1answer
32 views

Geometric Condensation Patterns on Windshield

I noticed these patterns in the condensation on the inner surface of my car's windshield when I turned on the defroster. Usually when I see lines like these on condensation I assume it's because of ...
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1answer
61 views

How can a battery 'come back to life'?

Earlier today, one of my family drained our car's battery by accident, by leaving the lights on too long. It wouldn't start at all, so they had to walk back home from where the car was parked (a few ...
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1answer
41 views

What does the universal gas constant, $R ,$ represent?

What does universal gas constant represent? My textbook says: it is the energy required to raise a ideal gas by 1K The Mayer formula is $$ C_{\text{p}} = C_{\text{v}}+R \,,$$ so isn't text book ...
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0answers
44 views

Is flame temperature and the temperature above the flame about the same?

This is a practical question that looks not that academic. I'm trying to design an integrated forge that can do heating and forging together. Blacksmiths usually make a forge kiln like Figure 2, as ...
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2answers
68 views

How to quantify the mixing of two hard-spheres gases?

Suppose that there are two types of hard-spheres gases ($a$ and $b$) in a box. Suppose that their radius is much smaller than the box's characteristic size. These two gases tend to repel each other. ...
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1answer
48 views

Given two substances of different specific heats, how do you find the final temperature and these phase related things

Given two substances of different specific heats, how do you find the final temperature of them both, phase of either substance if there was a phase change, and how much either substance has changed ...
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38 views

Does hot water turns to ice quicker than cold water? [duplicate]

I kept hot water by mistake in freezer and noticed that it turned to ice pretty quickly and then I simultaneously put hot and cold water in freezer, still the results were the same. How so?
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1answer
62 views

Champagne bubbles and gravity

One of the influences on bubble size is the speed with which a bubble rises in a glass - this, I believe, is due to the force of gravity which acts on the liquid around the CO2. The greater the ...
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1answer
68 views

In the value of gas constant $R$, what kind of mole is it?

Wikipedia gives $$R=8.3144598(48)\, \rm J\,mol^{−1}\,K^{−1}$$ But I want to ask how is it possible to write $\mathrm{mol}$ without a suffix? I mean, we must determine if we have $1\ \mathrm{mol}$ of ...
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0answers
26 views

Diffusion of liquid in sealed reservoir with no empty volume?

Think of this scenario... You have a sealed container of some sort filled with water and some sort of mystery fluid X. Let's say this mystery fluid X has a density of 1.5g/cm^3. In this container, ...
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2answers
77 views

Does stirring a liquid add heat $Q$ to a system? [closed]

I was given a question, "A thermos bottle containing milk is shaken vigorously. Consider the milk as the system. (a) Will the temperature rise as a result of the shaking? (b) has heat ...
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1answer
61 views

What is the law of mass action?

What is the law of mass action? This is a question which covers the area of chemistry. But unfortunately I don't know any sites which can clear my chemistry doubts. So kindly I request anyone to ...
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0answers
29 views

To which all factors chemical equilibrium is directly proportional to? [closed]

The equilibrium constant is directly proportional to the concentration. why it is so? Is chemical equilibrium dependent on temperature and other such factors? Then why we only focus on concentration?
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1answer
60 views

is fog matter, I knowthat stuff like fire arent but is fog matter? [closed]

I haven't found any other website which explains to me that fog is matter; I just need this to figure out what things are matter and which are not. For example, fire is NOT matter.
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Atomic bonding forces -

I was watching IBM's short film called How to move an atom and it got me thinking the following: Which element should one use as a surface in order to get the ...
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1answer
27 views

Does the presence of a flame affect the flow rate of gas out of a lighter or torch?

If I were to set a propane torch's valve to a fixed open position, would it run out of gas faster lit or unlit? Does the flame produce any kind of pressure change that affects the flow rate through ...
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1answer
100 views

Scientific explanation for smell? [closed]

This might be more on the philosophical side. We already know a lot about light. How it is generated and how it interacts with a material. Phenomenon such as Interference, Diffraction, the ...
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2answers
83 views

Physical meaning of quantized energy of electron (or n=1,2,3…) in Bohr's model

To solve objections on Rutherford's model, one of which is energy deficit, Bohr postulated that the energy of the electron is quantized and $n=1,2,3...$ . But what does this postulate mean physically? ...
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77 views

How did we first discover oxygen exists as $\rm O_2$ and not just $\rm O$?

How did we first discover oxygen exists as $\rm O_2$ and not just $\rm O$ ? (similarly hydrogen as $\rm H_2$ and not $\rm H$) I vaguely remember knowing a story about how the chemical formula of ...
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1answer
53 views

Basic energy question

How do we know something contain energy or not? P.S.: I don't really understand how energy should be interpreted. Until today I always thought that energy is some kind of magic that makes stuff ...
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24 views

Charge distribution in the Inner and Outer Helmholtz Plane (electrical double-layer theory)

The Gouy-Chapman double-layer model predicts the presence of a diffuse layer of ions in an electrolyte solution when approaching a charged surface. But in order to take into account the finite size ...
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61 views

What is the best book or site to understand how to construct Periodic Table, theoretically?

I want to understand how Periodic table is constructed theoretically and mathematically. But I can't find self-contained book or site about it by myself since I'm a computer science guy and lack of ...
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1answer
193 views

How many calories in a block of wood?

I was recently thinking about the human body and the energy we get from food. I understand we don't have the ability to properly digest certain things like stones and wood and grass, but if we did, I ...
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0answers
58 views

How to use Hund's third rule for excited electronic configurations?

Hund third rule states: For a given term, in an atom with outermost subshell half-filled or less, the level with the lowest value of the total angular momentum quantum number ${\displaystyle J\...
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0answers
80 views

Is $H_2O$ the only compound which has a density anomaly? [duplicate]

My question is simple: are there any elements, compounds or materials other than water ($H_2O$) which have a density anomaly characterized by a turning point in the $T-\rho$ curve?
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1answer
25 views

Which elements or isotopes can be analyzed by Neutron activation analysis (NAA)?

Some sources name only a handful, but that might refer to the use of optical film. Others state more than 70. I would like to know which elemets or isotopes can be detectet/imaged by NAA.
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1answer
35 views

For the $\mathrm{H}_2$ molecule which spin states correspond to bonding? and which spin states correspond to anti-bonding?

Do I understand correctly? In the case of the $\mathrm{H}_2$ molecule, the overall state is $S = \Psi(r)\chi(s)$.....(Spatial and spin aspects) $\Psi(r)$ is inherently anti-symmetric under exchange ...
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2answers
94 views

Chemical potential and equilibrium condition

My question is about the $dG=0$ condition for the equilibrium in a system, say, solid + gas (water and ice, if you prefer). Almost every textbook gives the following recipe to understand phase ...
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1answer
47 views

Water Bottle Condensation

My friends and I were at a party last night and we were crushing empty water bottles until the cap popped off and water vapor came out. I have two questions regarding this phenomenon. From previous ...
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Why it is the Schottky defect not non stoichiometric?

Why Schottky defect doesn't counted under non stoichiometric defects? According to me since they lose atoms their stoichiometry must change.
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1answer
73 views

How do scientists experimentally (this means not theoretically) determine that an atom is not bonded with any other atom?

What I do not understand is how scientists can tell whether or not an atom is bonded to another atom or all by itself. If someone can help me understand this, please do.