Unanswered Questions
712 questions with no upvoted or accepted answers
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Shielding vs electron-electron repulsion
Example of shielding:
(source)
The last electron in the 6s subshell of $\ce {Cs}$ is shielded from the nucleus by the inner electrons.
Example of electron-electron repulsion:
The electron affinity of ...
CommunityBot
- 1
3
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590
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How to use DSC to differentiate first and second order phase transition?
The DSC trace below was recorded for a thermotropic calamitic liquid crystal. The heating rate was 5 $^\text{o}$C min$^{-1}$; a heating scan is followed by a cooling scan.
Based on the previously ...
- 1,241
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Meaning of chemical potential in chemical reactions
In my thermodynamics course, we introduced the chemical potential as a modification of the first + second law of thermodynamics in the case of a system that can exchange particles with its ...
- 117
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Is dehydration of cobalt(II) chloride hexahydrate dynamic equilibrium?
I know that the dehydration of cobalt(II) chloride hexahydrate is a reversible reaction, is it a dynamic equilibrium?
$$
\begin{align}
\ce{CoCl2·6H2O &<=> CoCl2·2H2O + 4 H2O}\tag{R1}\\
\ce{...
- 38.4k
3
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What is meant by "analogous reactions" in the Bell-Evans Polanyi Principle?
The BEP principle says that for analogous reactions, enthalpy change and activation energy are linearly related. What is meant by analogous reactions?
Eg. For electrophilic addition of HBr to pent-1-...
- 51
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correcting Henry's Law coefficient for higher pressure
I have a bottle at room temperature that contains water, nitrogen, and a trace amount of vinyl chloride (VC). I'm trying to determine how much the Henry's law coefficient for VC (at 25 C and 1 bar, ...
- 31
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Gibbs free energy of mixing in a control volume
I'm trying to model the amount of energy lost due to mixing of a $\mathrm{HCl}$ solution using the Gibbs free energy of mixing. However, I really like a second opinion on the model and the results, ...
- 131
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How does the surface to volume ratio of ions and their distribution in solution compare to that of suspended nanoparticles in nanofluids?
I am interested in understanding the heat transfer capabilities of fluids.
Nano-fluids are suspensions of nanoparticles (1-100nm sized particles) in a base fluid, often water, oil or glycol. These ...
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100
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Practical meaning of omega potential
In statistical thermodynamics, the quantity omega potential is defined and is different for fermions, photons, phonons and other particles .
I have been understanding the derivations of omega ...
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458
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Why do we want to operate at dew point or bubble point when doing flash calculations?
I'm trying to dimension a flash drum for a separation between water and isobutane. I now the total inlet flow (F), the composition of the inlet flow ($z_1$ for isobutane and $z_2$ for water) and the ...
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What does isohydric solution mean?
While studying ionic equilibrium, I came across the term "Isohydric Solutions" which is defined as:
Solutions of electrolyte are said to be isohydric if the concentration of the common ion ...
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3
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239
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Calculating temperature of partial condenser, flash calculations
The iterative method I have learned to make flash calculations for a binary system where I know the inlet feed (F [mol/s]), total composition of the two components ($z_1$ and $z_2$), the amount of the ...
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Is standard change in activation Gibbs free energy indepedent of pressure?
For a chemical reaction the activation volume is defined as:
$$Δ^{\ddagger}V={V^\ddagger}-V$$
where both $V^\ddagger$ and $V$ refer to standard states (I have omitted the symbol for simplicity). One ...
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119
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How to find the equilibrium constant under non-standard conditions?
Given the following thermodynamic data at $\pu{298 K}:$
$$
\begin{array}{lrrr}
\hline
\text{Compound} & \Delta_\mathrm{f}H^\circ/\pu{kJ mol^-1} & S^\circ/\pu{J K^-1 mol^-1} & C_p^\circ/\pu{...
- 38.4k
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Correlating specific heat (Cp) of a substance with other substance on the basis of similar physio-chemical properties
I am modelling $\ce{H2O2}$ decomposition in ANSYS Chemkin-Pro and I have difficulty finding $C_p$ (specific heat at constant pressure) for liquid $\ce{H2O2}$ for various temperature ranges.
My ...
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