Questions tagged [physical-chemistry]
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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pH probe equation derivation
This is a bit of a niche question, but I am struggling to find a good answer just by Googling around. I've been reading recently into the function of pH probes and ion-selective electrodes in general.
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Orbital correlation diagram of cylobutane opening to ethylene
In one of the previous exams, we were asked to draw the orbital correlation diagram for the ring-opening of cyclobutane to two molecules of ethylene. The first step would be to draw the transition ...
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High School Chemistry Significant Figures [closed]
This problem appeared on my AP Chemistry summer work form, and I do not understand how to use significant figures to do this.
Here is the question word-for-word. Convert these from +- (plus-minus sign)...
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Decomposition Redox Rxn Vs. Intramolecular Redox Rxn
I'm trying to understand what is the difference between decomposition redox reaction and intramolecular redox reaction? Are they synonymous? Is there a reaction which belongs to one but not the other ...
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Why is the Molar mass of CO2 different than the weight of the sum of its particles?
The Molar mass of CO2 is stated to be 44.009 grams per mol
But in a calculation of the weight of each atom's particles((Electrons,Protons,Neutrons) times Avogadro's constant
I get 44.36 grams per mol
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Why is Law of Multiple Proportions not valid for isotopes? [closed]
I read that this law is invalid for isotopes but can't find any example to prove it(i don't know much about compound with different isotopes).
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Why do discrete states of matter exist as opposed to a continuous spectrum?
Why is it that bonds are broken at certain temperatures (melting and boiling points) only, that thermal energy is converted to kinetic energy at all other temperatures (and not potential energy)? This ...
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Deriving the law of mass action from first principles
I have always been interests on how from first principles you can get kinetic equations. Not models made specifically for a system but coming from thermodynamics and QM.
But the law of mass action is ...
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Expressing the Lorentz-Lorenz equation for molar mass
In it's most general form, the Lorentz-Lorenz equation is given by
$$\frac{n^2 - 1}{n^2 + 2}= \frac{4 \pi}{3} N \alpha_\mathrm{m},$$
where $n$ is the refractive index, $N$ is the number of molecules ...
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How to Prepare Vanadium (Na3VO4) solutions buffered at pH = 7.5?
"I need to conduct adsorption studies on Vanadium using various substances like biochars and nanooxides. To prepare Vanadium solutions up to 320 ppm with a pH buffered at 7.5 using PIPES buffer, ...
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what really happens when an electron pair is shared in a bond?
I've never been able to understand how bonding between two atoms works.
When two atoms share an electron pair, does it mean the valence electrons of both atoms stop revolving in their shells and stop ...
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Identifying the rate-determining step from an energy-reaction coordinate diagram
I was wondering how a rate-determining step would be identified for an energy-reaction coordinate diagram. The RDS would be the step with the highest activiation energy, but relative to what? Relative ...
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Is the surface electron affinity of (tribasic) sodium- or calcium phosphate higher?
Let's imagine we have two polycrystalline samples: $\ce{Ca3(PO4)2}$ and $\ce{Na3PO4}$. A free electron is added to both. Some heat is released.
I wanted to check whether my reasoning about this ...
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London forces and van der Waals interactions
London or dispersion forces are considered to be type of van der Waals (vdW) interactions or inter-molecular forces that are neither ionic or covalent. However, is there way to distinguish dispersion ...
user74793
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Why can't I conserve mass instead of moles and apply ratio in this problem?
I was solving this problem:
$S$ combines with $O_2$ to form $SO_2$ and $SO_3$. If $10g$ of $S$ is mixed with $12g$ of $O_2$, what mass of $SO_2$ will be formed, so that neither $O$ nor $S$ will be ...
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