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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...].

Physical chemistry deals with the study of macroscopic and microscopic phenomena in chemical systems in terms of physical laws and concepts [thermodynamics, statistical mechanics, kinetic theory, quantum mechanics ...].

Some of the subfields that physical chemistry includes are:

  • Quantum chemistry.
  • Chemical kinetics.
  • Surface chemistry.
  • Electrochemistry.
1357 questions
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Why does ice cream get harder when colder?

What would seem to be a silly question actually does have some depth to it. I was trying to scoop out some of my favorite soft name-brand ice cream when I noticed it was frozen solid, rather than its usual creamy consistency. After leaving it out…
TheEnvironmentalist
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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 ?
Ilya Gazman
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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 to spread out and coat the entire surface.…
knzhou
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Why do grapes in a microwave oven produce plasma?

Some of you may know this experiment (Grape + Microwave oven = Plasma video link): take a grape that you almost split in two parts, letting just a tiny piece of skin making a link between each half-part. put that in a microwave oven, and few…
JBE
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What enables protons to give new properties to an atom every time one is added?

How does adding one more particle to the nucleus of an atom give that atom new properties? I can see how it changes it's mass, that's obvious... But how does it give that new atom different properties like color? A good example would be: start with…
Investor
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How small can a flame get?

Last time I was watching a candle die. After its wick was finished, there remained just a drop of molten wax that was still slowly burning, with a flame that became smaller and smaller, down to a millimeter high, until it disappeared. It made me…
Anthony Guillen
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Can a radioactive atom be prevented from decaying if it's in a REALLY strong chemical bond?

So, based on this question, a molecule containing a radioactive atom will break when the atom decays. But suppose you need a lot energy to break the compound apart --- as in, more energy than the decay of the atom will release (obviously, a molecule…
Palbitt
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Why does sound absorption in oceans depend on the pH?

I was reading "The Sixth Extinction: An Unnatural History", by Elizabeth Kolbert, and there she comments that high level of $CO_{2}$ in the atmosphere lowers the pH of oceans (which makes sense) and, consequently, diminishes sound absorption: WHY…
Gabriel Cozzella
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Because things smell, is everything evaporating?

Everything, in theory, can have a smell, but that is not the whole point of this question. My main query is, since things do smell, does that mean that everything is slowly evaporating (or, sublimating, I suppose)? For example, if we perceive metal…
deed02392
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Why do rotten eggs float in water?

My mom told me that one can check whether an egg is rotten by sinking it in a glass of water. If it floats, then it is rotten. I didn't find any explanation for this phenomenon. If anyone knows one, please answer.
prAnjal
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Why doesn't increasing the temperature of something like wood or paper set them on fire?

Imagine we have paper book. If we put this into a pan and increase its temperature, this book would not catch on fire. If on the other hand the book interacts with this heat source directly, it does catch fire. What is the difference between these…
M. Çağlar TUFAN
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Why doesn't soda go flat immediately after opening?

So, soda is under pressure and has gas dissolved in it. But, when you open it, the gas is still dissolved in it. But, if we wait a few hours, the gas has escaped into the atmosphere. What factors determine the rate at which gas escapes the soda-gas…
Mohammad Athar
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Why isn't the molecule of water linear straight?

When you see models of water you see something like this: The hydrogens in the water molecule become negatively charged because the oxygen pulls electrons more. So why don't they repel and move to the opposite sides of the oxygen? Or just form on…
Trevor Blythe
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When I put my hand on a hot solid why don't the particles transfering heat to my hand exert a force on it?

When I put my hand on a hot metal (say) solid, I can feel my hand heating up. I suspect this is caused mostly by particles (electrons, atoms, ...?) from the solid colliding with the particles that make up my hand thereby transferring kinetic energy…
Damian Birchler
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Where should a physicist go to learn chemistry?

I took an introductory chemistry course long ago, but the rules seemed arbitrary, and I've forgotten most of what I learned. Now that I have an undergraduate education in physics, I should be able to use physics to learn general chemistry more…
Mark Eichenlaub
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