Unanswered Questions
286 questions with no upvoted or accepted answers
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Mathematical models of oscillatory chemical reactions
I am a mathematician working on real-life models in ordinary differential equations. I want to know if there are any models of oscillatory chemical reactions that consist of three ordinary ...
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6
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Approximating entropy change in a reaction using Arrhenius equation
Recently my teacher finished teaching the chapter Chemical kinetics in which I have gone through Arrhenius equation.Can we estimate the change in entropy using it? I have done my calculation, ...
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6
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1
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Understanding elementary rate laws from a probability stand point
I am learning about chemical kinetics and dynamics and as I understand for a general chemical reaction
$$\ce{aA + bB -> cC + dD} $$ whose reaction rate, r, can be described by an elementary rate ...
CommunityBot
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6
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Reaction rate constants for methane combustion
I can't find a rate constant or activation energy for the methane combustion reaction given by:
$$\ce{ CH4 + 2O2 -> CO2 + 2H2O}$$
Do all reactions have a rate constant? The NIST web site lists ...
6
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2k
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Finding theoretical mechanism of sodium thiosulphate and hydrochloric acid
In class we conducted an experiment where we timed reactions between sodium thiosulphate and hydrochloric acid. We kept the concentration of the $\ce{HCl}$ constant, while changing the concentrations ...
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6
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Is there a bifurcation node in the potential energy as a function of reaction progress equation of chemical reactions?
I originally posted a similar question on math.stackexchange.com, but I believe I might have a better chance of having my question answered here after giving it some time.
I was thinking about the ...
CommunityBot
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5
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608
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Explanation of the trans-effect (thermodynamic and kinetic) for octahedral transition metal complexes
The thermodynamic trans effect refers to the ground state weakening of the metal-ligand bond in a complex by a ligand trans to it. The kinetic trans effect is the lablisation of a ligand in a complex ...
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Calculation of rate constant for bimolecular reaction from Gaussian DFT calculations
I am working with a bimolecular reaction for which I have computed the energy profile. I have output files for TS and reactants which I intend to use for rate constant calculations. From TST we have:
...
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5
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183
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Why do aldehydes polymerize faster in the cold?
In amateur perfumery, raw chemicals are usually stored in sealed bottles in refrigerators/freezers to reduce decomposition rates. However, aldehydes are tricky to store for long periods of time ...
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Should I round an experimentally determined reaction order to an integer?
For a lab experiment I did, I calculated the reaction order for one of the reactants using data from two trials, both rates, and the concentration of that reactant during each.
$$
\frac{\text{Rate}_1}{...
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4
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Does the E1cb elimination mechanism have a first-order or a pseudo-first order rate law?
Elimination reactions turning a single C-C bond into a double bond are classified as E1, E2, or E1cb, depending on the mechanism (concerted or with intermediate), the stereochemical outcome and their ...
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4
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Rate of polymerization for copolymers with two monomers
I've found in textbooks that for a chain growth homopolymerization the rate of polymerization $r_\mathrm{p}$ is
$$r_\mathrm{p} = k_\mathrm{p}\sqrt{\frac{f_\mathrm{kd}}{k_\mathrm{t}}}c_\ce{A}^ac_\ce{B}^...
- 38.4k
4
votes
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563
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Lindemann–Hinshelwood mechanism for a gas reaction
The effective rate constant for a gaseous reaction which proceeds by a Lindemann–Hinshelwood mechanism is $\pu{1.01E-5 s^-1}$ at a concentration of $\pu{4.6E-6 M}$ and $\pu{2.21E-5 s^-1}$ at a ...
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4
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What do the phase space and slope fields of the iodine clock reaction look like?
The iodine clock reaction is a fun experiment shown to undergraduates to illustrate that chemical reactions can show periodic behaviour. Presumably, or hopefully, there is a system of differential ...
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4
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Decomposition of Hydrogen Peroxide Catalysed by Potassium Iodide in Basic Solution
As part of my high school project, I had to measure the initial rate of decomposition of hydrogen peroxide catalysed by potassium iodide at different pHs. At higher pHs (alkaline conditions), I found ...
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