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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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Mathematical Resolution of Overlapping Signals

I would like to take the opinion of physicists (my area is chemistry). During instrumental analysis, the output is a instrument response vs. time. Each peak corresponds to a molecule which is ...
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1answer
41 views

Why are there less bubbles the second time I pour soda in the cup?

I poured some Pepsi into a mug, and it foamed, and I poured until the foam was at the top of the glass. I waited a few seconds for the bubbles to go, and the liquid level was revealed to be at around ...
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1answer
26 views

Specific Heat, Conservation of Energy, and Kinetic Energy

Different molecules have different specific heats, such as water, which has a very high specific heat due to strength of inter-molecular attractions. If temperature is the random kinetic energy of ...
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2answers
50 views

Finding partial molar volume from an algebraic expression

I'm given the equation $ V = 120X_1 + 70X_2+X_1X_2*(15X_1+8X_2)$ and told to calculate $\bar V_1 $ & $ \bar V_2$ and then to show that $ V = \Sigma_i X_i*\bar V_i$. Since there are two mol ...
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1answer
50 views

Why hot soup is tastier than cold soup? [closed]

My physics teacher recently asked me this question. Can anyone answer the question?
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4answers
55 views

Bicycle Fuel equivalent on l/100km

Is there a way I can calculate the equivalent how much a Human powered bicycle consumes in the equivalent l/100 Km of Diesel fuel? And also can I calculate the same for Gasoline fuel? And for ...
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0answers
40 views

Van der waals forces interaction

My slides say: A gas with low density in which you can consider the attractive energy the sum of the isolate atoms couple $$ u=\int^S_\sigma{4\pi\frac{N}{V}}\left(\frac{\beta}{r^6}\right)r^2\...
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0answers
14 views

How centrifugation works?

Can someone explain how centrifugation works to seperare substances ? Isnt centripetal force what actually makes the seperation?
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11answers
7k views

Are there physical properties that can be used to differentiate stainless steel from copper in a home environment? [closed]

So the backstory is that I purchased a reusable drinking straw that is copper coloured, but is advertised to be stainless steel. That got me thinking about whether I could be sure it was one or the ...
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0answers
13 views

Bond Nature of a comound [closed]

How can we determine the type of Bond in LiBaPO4? can we find out the nature of bond through charge transfer values of these elements? if yes then how?
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0answers
46 views

Gibbs free energy the 3 equation confusion

Hello can you please help me with thermochemistry? I have been taking chem classes since highschool and they ALL talked about Gibbs free energy, enthalpy, and entropy... even in college I got away ...
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0answers
37 views

Why hydrogen bond forming has lifetimes on picosecond scale?

According to this Research http://www.kinetics.nsc.ru/mds/downloads/2009_JSC_Naber_Vol_LifeTime.pdf hydrogen bonds are formed and destroyed within a timescale of a few picoseconds. Why hydrogen ...
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1answer
29 views

Nucleus in the wires

Can someone explain why we consider the electrons to move through a wire and not the nucleus? Couldnt atoms get ionised with losing a proton?
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0answers
14 views

Potential energy of molecule [duplicate]

Does potential energy of molecule and therefore bond length change with temperature?
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0answers
23 views

Bond energy and tempetature

Does bond energy depend on temperature? Also why is it defined at 298 Kelvin if some substances cant be in gas phase in that temperature?
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0answers
35 views

Why are(n’t) rechargeable batteries damaged by partial charging?

Originally asked in ElectricalEngineering.SE, but I was told Physics.SE might be a better place to ask. Over the years, I've come across websites and people with different opinions on the "correct" ...
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1answer
29 views

How will the Big Rip affect chemistry and nuclear interactions?

The "Big Rip" is a theoretical scenario for the death of the universe. Let's assume that this scenario is true. What can we expect to happen to chemistry and nuclear interactions in the time ...
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1answer
19 views

Charge density of sea water

If sea water contains salt ions and some H+ and OH- ions, what are the charge density of a certain volume of sea water? And is there a way to calculate?
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1answer
42 views

Why doesn't lithium form di-lithium crystals? (Calling Mr.Spock)

Hydrogen is in the first column of the periodic table. At STP it is a di-atomic gas. When cooled and/or under pressure it forms a crystalline solid of di-hydrogen molecules. Calculations indicate ...
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0answers
92 views

Why is Argon a noble gas?

Why is Argon a noble gas given that the 3d subshell is still empty? I understand that in Helium the n=1 level is full, so it is a noble gas. Now, Beryllium has a full 2s subshell but it is a metal. ...
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1answer
32 views

Constant pressure

When we refer to constant pressure like in Charles law what is this pressure? The pressure of the gas or the pressure that the container (the piston maybe) exert on the gas? Also does atmospheric ...
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2answers
56 views

What is the energy of an atomic orbital?

When we refer to energy of an atomic orbital what is this energy ? is potential energy ? but if is potential energy then shouldn't be considered the whole potential energy of the atom ( potential ...
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1answer
54 views

What are some molecular systems which have quantum states that are measurably incompatible?

What I'm looking for is a molecular system, which we can produce in a lab, that is, A discrete variable system (ie, a finite dimensional hilbert space) It has observables that are incompatible with ...
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4answers
6k views

Why doesn't water actually perfectly wet glass?

According to many high school textbook sources, water perfectly wets glass. That is, the adhesion between water and glass is so strong that it is energetically favorable for a drop of water on glass ...
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1answer
54 views

When putting water on two pieces of paper they bond. Is that due to van der Waals bonds?

I've been wondering what keeps two pieces of wet paper together when in contact. Does water have any adhesive property? Or does it decompose something from the paper and creates some kind of glue? I ...
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1answer
38 views

Interaction between molecules

Does the interaction with enviroment change the geometry of a molecule ? for example in H2O the angle betwen H-O-H is 104.5 degrees. Does this angle change for example if the molecule of water is near ...
2
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0answers
40 views

Chemical potential of a reaction

I often see two various forms of the species $i$ chemical potential $\mu_i$ in a chemical reaction, in terms of enthalpy of formation $\Delta h_{f,i}^0$ and standard state entropy $s_i^0$. My ...
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0answers
26 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
22 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
33 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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0answers
34 views

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
92 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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1answer
17 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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2answers
77 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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0answers
183 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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0answers
30 views

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 ...
116
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6answers
12k views

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
28 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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3answers
48 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
43 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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0answers
23 views

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
45 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
65 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
44 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
47 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
74 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
58 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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1answer
64 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
71 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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2answers
126 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 ...