# Questions tagged [kinetics]

The study of rates and steps in mechanisms of chemical processes.

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### Finding the average rate of consumption

The question is: If $2.0 \cdot 10^{-4}$ moles of dye in $\pu{50 mL}$ of solution is consumed in 188 seconds, what is the average rate of consumption of dye in $\pu{mol L-1 s-1}$? I am not sure if I ...
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### Evaporation velocity of ethanol: adding ethanol vapour to a gas mixture

I need to add a known amount of ethanol vapour to a gas mixture (He/Ar). To do that I let the mixture bubble in liquid ethanol kept at a known temperature (14 C). The system is made of a large steel ...
769 views

### Determining order of a reaction without isolation

I'm writing a computer program to calculate the order of a chemical reaction with respect to each reactant. When I do this by hand, it's easy to isolate which reactant concentration stays relatively ...
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### Which of the these SN1 solvolysis of two alkenyl bromides reactions is faster?

The SN1 solvolysis of one of the following alkenyl bromides is in MeOH approximately 100000 times faster than the other one. Which is the more reactive one? Draw the mechanism including the transition ...
1 vote
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### How do I calculate the order of a reaction given slope?

I'm an AP Chemistry student, and we're doing the Decomposition of $\ce{H2O2}$ lab, in which we decompose $\ce{H2O2}$ with $\ce{KI}$ as a catalyst. I've gotten this data so far: ...
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### How to calculate the frequency of cyclohexane conformational interconversion?

My book mentioned that the energy barrier for cyclohexane to reach the half-chair conformation is $50.6\ \mathrm{kJ\ mol^{-1}}$. It says that from this value, it was calculated that cyclohexane ...
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### How can molecularity be the order of the rate determining step?

In my textbook the molecularity is defined as(along with the standard definition) the order of the rate determining step(RDS). It is also given that the order can be a fraction but molecularity is ...
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### What is the scaling for % completion time in a Michaelis–Menten scenario as a function of substrate concentration?

Say I have a straightforward Michaelis-Menten reaction where an enzyme $E$ at some fixed concentration $[E]$ forms an interaction complex $ES$ with a substrate $S$ (with initial concentration $[S]_0$),...
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1 vote
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### Storing kinetic energy in bonds

Let's assume a setup with a static linear molecule with three identical atoms connected by bonds and a single atom, identical to the other three, being shot at the molecule. Let's also assume that ...
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### Difference between the terms "autocatalysis" and "(branching) chain reaction"

Is there a technical difference between the terms "autocatalysis" and "branching chain reaction"? They both seem to refer to something very similar, namely sequences of reactions in which one of the ...
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### What are the factors controlling the fate of post-adhesed volatile molecules of the olfactory epithelium?

What happens to volatile molecules that reach the main olfactory epithelium in the nasal cavity after they bind and the neural stimulus fades? To what extent do such factors as receptor kinetics and ...
444 views

### Integrated rate laws

My teacher gave us the equations for zero-order, first-order and second-order reactions as follows: $$[A]_t = -akt + [A]_0$$ $$\ln [A]_t=-akt+\ln [A]_0$$ $$\frac1{[A]_t}=akt+\frac1{[A]_0}$$ ...
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### What reactions will their reaction rates increase with time?

My textbook states that for most reactions, the reaction rate decreases with time. I wonder what reactions will have increasing reaction rates with time. I know that adding a catalyst will increase ...
472 views

### 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 ...
137k views

### Difference between thermodynamic and kinetic stability

What is the difference between thermodynamic and kinetic stability? I'd like a basic explanation, but not too simple. For example, methane does not burn until lit -- why?
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### A first-order reaction at infinite concentration

I have a first-order reaction, for the binding of two molecules, of the form: $\text{k}_\text{f} = \ce{k_1 (M*s)^{-1}}$. What happens at infinite concentration? How is this upperbound typically ...
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### Introduction to modeling chemical reactions

I am looking for introduction to modeling of chemical reactions. I think there is the base approach, where concentrations of chemical species are given, plus ratios of each possible reaction / outcome....
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### Very slow chemical clock reaction

I'd like to preface this with a declaration of my understanding that this is not necessarily possible. I was wondering if anyone knew of a chemical clock reaction where the period before the first ...
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### Algebra of conserved quantities for chemical reactions

So there is the standard formation enthalpy $\Delta H^0_f$ and there is also formation entropy. Are there more (independent) quantities? What about the heat capacity? Is there a general theoretical ...
319 views

### Difference between non-thermal and thermal ionized gases

Why or when does non-thermal plasma become thermal? How do we know before hand if the ion temperature will differ from the electron temperature, on what parameters does it depend - where is the ...
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### Why is a metabisulfite / starch / HCl solution unstable?

In one variation of the iodine clock demonstration, you add two colorless solutions together and apparently nothing happens. After about 30 seconds to a minute, you get an "instantaneous" change to a ...
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### What is the probability of 3 possible products, between two chemical species?

I am not a chemist. I hope I will be specific enough. Suppose there are two chemical species $\ce{A}$, $\ce{B}$ with the following properties: at temperature $t < T_r$, no reaction occurs between ...
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### Definitions of autocatalysis

Is there a formal definition or algorithm that can take a list of reactions and tell me whether it contains a set of species that can produce itself autocatalytically? It is clear that the following ...
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### What's a minimal yet chemically-meaningful kinetic system for an oscillating reaction?

Oscillating reactions are a funny aspect of chemistry. I have tried to find various simplified kinetic models of oscillating reactions such as the Belouzov-Zhabotinsky, the Briggs–Rauscher or the Bray–...