Questions tagged [reaction-control]

Questions related to the chemical and physical influences that influence the rate and probability of chemical reactions. Not to be confused with [catalysis] or [reaction-mechanism].

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14
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2answers
1k views

Does gravity affect the rate of a chemical reaction?

For example, on planets with lower gravity, would the rate of reactions be lower because the reactants are slower to mix with one another?
-1
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1answer
3k views

Can the summation of activation energy and reactant's initial internal energy change with temperature?

Look at the graph. The orange arrow represents the summation of activation energy and reactant's initial internal energy. Can it change with temperature? Is there any specific name for this summation?
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0answers
186 views

Aluminium etching

I'm trying to etch a very fine pitch ($\pu{0.5 mm}$) aluminium stencil for use with SMT printed circuit board making. I've done some reading on the topic and found that the safest way probably is to ...
1
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1answer
205 views

How to stop a lye + oil + water reaction in aluminium container?

I was making soap using a guide for the first time. I accidentally used an aluminium container. It has lye and olive oil in it and was kept on the stove; now it is bubbling and not ceasing (I've ...
7
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3answers
7k views

Why do we need sulfuric acid in creating alkyl bromide and not in creating alkyl iodide from alcohol and hydrogen halide?

i) $\ce{R-CH_2-OH + HBr ->[H_2SO_4] R-CH_2-Br + H_2O}$ ii) $\ce{R-CH_2-OH + HI -> R-CH_2-I + H_2O}$ What role does sulfuric acid play in the first reaction? Why are we not using it in the ...
10
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2answers
239 views

Chemical oscillators that behave like a double pendulum

Oscillating chemical reactions such as BZ-reaction or chemical clock typically result in sequential systematic changes, most notable of which is arguably coloring. Though underlying mechanism can be ...
-2
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1answer
57 views

Formation of α,β-unsaturated ketones

In Claisen-Schmidt condensation I've used $\ce{NaOH}$ catalyst. Can I use $\ce{KOH}$ instead of $\ce{NaOH}$?
8
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4answers
24k views

Why should the temperature be maintained at 0–5 °C in a diazotisation?

I know that in a diazotisation reaction, the temperature should be carefully maintained within the range of 0–5 °C by use of an ice bath. Why is this so? How does the temperature affect the stability ...
2
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0answers
32 views

Enantiomers in anisotropic achiral chemical environments

Consider a functionalised molecular box or cage which has an electrostatic gradient due to positively charged groups one one of its faces. This environment is achiral as there are reflection ...
5
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1answer
3k views

Python package for modelling chemical reactions

I'm looking for a package that is compatible with Python 3 and can actually do work with reactions along with, for instance, referencing values. Ideally, it should also not be a package that will take ...
3
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1answer
113 views

Continuous chemical reaction network versus chemical reaction network - difference?

I'm reading a paper entitled Reachability Problems for Continuous Chemical Reaction Networks and as I was reading it I realized: I have no idea what the difference is between a continuous chemical ...
12
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1answer
625 views

Noyori hydrogenation and the Curtin–Hammett principle

My question is relating to how the Curtin–Hammett principle applies to homogeneous hydrogenation using chiral ligands. Figure 0: An example of a quadrant diagram used as a mnemonic to predict the ...
2
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0answers
191 views

Can activated charcoal retain adsorbtion properties even when submerged in liquids?

This is following a question on Skeptics Stackexchange, where apparently medical science claims that activated charcoal can adsorb poison when ingested. One of the members posted a related question on ...
1
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0answers
165 views

Could stabilized aqueous ozone be bottled to prevent half life/sanitization window?

Could stabilized aqueous ozone be bottled to prevent half life/sanitization window? Typically upon creating stabilized aqueous ozone, it has a shelf life and a sanitization window of 24 hours from ...
1
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1answer
806 views

Why is the product of the reaction between iron and steam is iron (II, III) oxide and not iron (II) oxide or iron (III) oxide? [duplicate]

The reaction between Iron and steam in my textbook is given as this: $$\ce{3Fe + 4H_2O <=> Fe_3O4 + H_2} $$ My question is why these following reactions are not possible or do not happen. $$\...
7
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0answers
97 views

How well will molten iron chrysolite (fayalite) react with hydrogen?

The equation balances nicely, but would the reaction tend to proceed this way? What temperature and time would be needed? $\ce{Fe2SiO4 + 2H2 -> 2H2O + 2Fe + SiO2}$ There is no problem with ...
1
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0answers
188 views

Will Ethanol degrade Silicone or “RTV” specifically “RTV 734”, or cause it to “leach” ingredients at temperatures below 250 degrees farenheit?

Will Ethanol degrade Silicone or "RTV" specifically RTV 734, a flowable sealant produced by Dow Corning, or cause it to "leach" ingredients at temperatures below 250 degrees Fahrenheit? Such as in ...
3
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3answers
126 views

Why do some reactions need to be maintained at a particular temperature for prolonged periods of time?

Some reactions require that temperatures of 70–100 °C to be maintained for periods of time as long as 24 hours. Why is this so?
1
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1answer
67 views

Hydration reaction

Currently I'm measuring the rate of completion of a hydration reaction by putting a temperature probe in the middle of a cup full of reagents and measuring the temperature in an isolated box. The main ...
3
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1answer
495 views

Equation for collision frequency of molecules/ions in aqueous solution?

There are equations that describe collision frequency in the gas phase, but I am wondering if this collision theory has been extended to describe the collisions of molecules and/or ions that are ...
0
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2answers
137 views

Dimethylene Cyclohexane to Octalin-1,4-Dione | Hydroboration vs. Ozonolysis Pros Cons

With regards to the following synthesis, what are some pros and cons of using hydroboration oxidation followed by oxidation of the alcohols compared to ozonolysis. More specifically, how do the two ...
3
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1answer
607 views

How does haloform reaction take place if the reactants NaOH and X2 react with each other?

If $\ce{NaOH}$ reacts with halogen to produce $\ce{NaX}$ and $\ce{NaXO3}$, then how does haloform reaction take place?
3
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3answers
866 views

Hydrogen reactions with catalysts

I have a question about reactions involving hydrogen using catalysts. I'm a layman, so forgive me if my questions seem elementary. Reacting hydrogen plus oxygen and a flame reacts, unleashing energy (...
2
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1answer
625 views

Carbylamine Reaction

In my lab manual, it is given that alcoholic KOH should be the base used in carbylamine test. However as it was not available, I used 10℅ NaOH. The test results came out positive. (Yes, it was ...
2
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1answer
133 views

Rate of Reaction for Elementary Reactions

The rate law for an elementary step of a reaction of the form $2A \Rightarrow$ Products is given by $rate=k[A]^2$, while in the form $A \Rightarrow$ products is given by $k=[A]$. Is there some sort of ...
6
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1answer
21k views

Prove that a 10-Degree Temperature Increase Doubles the Rate Constant (k), when the Activation Energy is Approximately 50 kJ/mol

I read that increasing the temperature by $10~^\circ\mathrm C$ will double the rate constant ($k$), when the activation energy for the reaction is relatively close to $50~\mathrm{kJ/mol}$. However, ...
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0answers
70 views

Mathematical model for reaction rate in fixed volume

Is there a way to find the rate of reaction of a chemical reaction inside a closed container that is fixed in volume as a function of time? Can the answer provide an example reaction (such as baking ...
12
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2answers
2k views

How does heptafluoropropane suppress fire?

How does heptafluoropropane suppress fire? It says here that it does so by "inhibiting the chain reaction." What does that mean specifically? Does $\ce{O2}$ attach itself to the heptafluoropropane?...
25
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1answer
29k views

Addition of hydrogen bromide to 1,3-butadiene: thermodynamic and kinetic control

The reaction of one equivalent of hydrogen bromide with 1,3-butadiene gives different products at under different conditions:1 The addition of hydrogen chloride also gives rise to similar products.2 ...
5
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2answers
1k views

Thermodynamic vs kinetic reaction control with radical substitution

Doing a revision for a chemistry class test tomorrow, I stumbled upon thermodynamic and kinetic reaction control in the context of radical substitution. Here, my chemistry teacher said, that ...
1
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0answers
411 views

Water-gas shift reaction without catalysts

I'm designing an experimental gas generator. The details are not really important here, but I want to convert a mixture of carbon monoxide, hydrogen and $\ce{H2O}$ gas to a safer form. I know the ...
1
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1answer
2k views

Effect of temperature in the free radical polymerization of acrylic acid

I am working with the model of a free radical polymerization process in a tubular reactor. In the simulations, I observe that by keeping the feed flow of the initiator (sodium persulfate) and the ...
1
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1answer
38 views

When DNA degrades, does any chemical environment preserve sequence information?

Small bits of DNA information can be found in ancient remains. In analogy to old bones becoming mineralized, is there a chemical environment in which the nucleic acid sequence of the original strand ...
5
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4answers
378 views

how to mathematically predict reaction results

I've been trying to computationally achieve the following (I have no lab, I'm 14 years old, and I want to make a Minecraft mod to teach real Chemistry): I want to mathematically predict the range of ...
2
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1answer
4k views

Is enthalpy of activation the same as activation energy? Is there a purely mathematical way to find that value?

I asked about the effect of pressure on a reaction, and since then I learned a lot more. One of the things I learned was the Eyring equation: $$\kappa = \frac{\kappa_B T}{h} e^\frac{\Delta^\ddagger S°...
4
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3answers
1k views

Why do some reactions require specific pressures to happen?

For example, carbon monoxide reacts with hydrogen to synthesize methanol in the presence of some catalysts, but the pressure needs to be $\pu{50 atm}$ and the temperature needs to be $\pu{523 K}$. ...
0
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1answer
52 views

Reaction control on molecular level

Imagine I have a bottle with a random quantity of molecular hydrogen, and can apply exactly enough energy to break only one molecule of hydrogen. Is the reaction going to occur or the energy would be ...
1
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2answers
4k views

Diffusion-controlled reactions, activation-controlled reactions and rate equation

I am confused as to where the rate equation can be applied and where not to be applied. https://en.wikipedia.org/wiki/Rate_equation In diffusion-controlled reactions from what I understand reaction ...
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0answers
34 views

Return time after perturbation in a chemostat

I'm wondering how I can derive the return time of the culture cell concentration back to a steady-state in a chemostat after a small perturbation of the bulk culture cell concentration. More specific,...
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0answers
200 views

Chemical equilibrium and Le Chatelier Braun for ammonia production

In the book of Chemical, biochemical and engineering thermodynamics 4th edition from Stanley I. Sandler (Wiley, 2006), there is a problem about the ammonia producing reaction at page 770. 13.17 The ...
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2answers
1k views

Rate determining step

The formation of the cation is the rate-determining step. we can look at this in two ways. Either that a cation is an unstable species and so it will be formed slowly from a stable neutral organic ...
2
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0answers
64 views

Is there wavefunction interference between alternate reaction pathways?

I'll give a specific example to clarify my question. If we look at the approach of chloromethylenecarbene's electron pair to cis-2-butene in the reaction of creating 1-chloro-2,3-dimethylcyclopropane, ...
0
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1answer
662 views

Calculating time taken for a set percentage of a reaction to occur based on half-life

The half-life of a first order homogenous gaseous reaction: $\ce{SO2Cl2 -> SO2 + Cl2}$ is 8.0 minutes. How long will it take for the concentration of $\ce{SO2Cl2}$ to be reduced to 1% of the ...
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2answers
10k views

Reactivity towards SN1 reaction

In the following compounds , we have to find order of compounds of their reactivity towards SN1 reaction. According to me , we should compare carbo cation stability which is formed as an ...
5
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0answers
49 views

Increasing C-alkoxycarbonylation of enolates

I am working with N-tosyl-2-piperidone and attempts to use the lithium enolate of this compound to perform an nucleophilic acyl substitution reaction on an several chloroformate esters in THF has lead ...
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0answers
46 views

Limit the production of hydrogen in a small container

I have to produce hydrogen at a near-constant pressure inside of a really small container without using an automatic pressure release value. I would like the pressure to be relatively high, but the ...
4
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2answers
9k views

Relationship between Gibbs free energy, enthalpy, entropy and rate of reactions

I'm having a little trouble constructing the bigger picture of chemical reactions. From the collision theory we know that molecules react if: 1) they collide 2) they collide bearing a sufficient ...
0
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1answer
27k views

Does changing the volume of a reactant affect the rate of reaction? Does changing the volume of HCl affect the rate of a Mg & HCl reaction?

I'm doing a experiment in which I'm testing the affect of the concentration of a reactant on the rate of reaction. The reaction is between Magnesium and Hydrochloric Acid and so I'm changing the ...
5
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0answers
108 views

Is there a way to force C-protonation of an enolate?

In another question, I mentioned that O-protonation of an enolate followed by tautomerization may lead to increased amounts of the thermodynamic product over the kinetic product (when those are ...
3
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2answers
2k views

Thermodynamic versus kinetic reactions

In a lecture, teacher said "Nucleophilicity is about 'kinetic', and basicity is about 'thermodynamic'" but I saw the picture below from another source. Here, both pathways start with an acid/base ...