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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How much "free ammonium" would be present in a solution of ammonium and citric acid?

I am making a mixture. I start with aqueous ammonia (aka ammonium hydroxide) that is 10% NH3 by weight (roughly 8.2% N by weight). I add 50 grams of citric acid (dry powder, 100% purity) to 1 L of the ...
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Minimum condition for the dehydration of primary alcohol

What does it mean by the solution should be concentrated by $\ce{H2SO4}$ up to 95% with a temperature of $\pu{443 K}$ for the dehydration of primary alcohol? Dehydration of primary alcohol: $$\ce{CH3-...
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3 answers
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Can we make chemical bonds using light, instead of breaking them?

I am trying to bridge a conceptual understanding of how light affects both breaking and forming bonds. When bonds are broken, energy is absorbed (endothermic process). Conversely, when bonds are made, ...
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Oxidation Reactions/Reactivity of Manganese Metal in Air and Water

I am planning on doing some reactions that lead to Manganese metal and a neutral solution containing $\ce{Mn^{2+}}$ as by-products, and I wanted to try some things out with the Manganese as well. ...
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What are the reaction rate constants, or coefficients, of coal combustion at high temperature?

Say I have coal that I will combust with $\ce{O2}$ at a high temperature of $\pu{1600-1800 K}$, what are the reaction rate constants, or coefficients, of the main reactions? I have searched around ...
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How do you rewrite molarity to weight percentage or volume percentage?

Suppose I have a molar concentration $[C]$ in $mol/m^3$ in a continuous reactor, from which the differential equation is as follows: $ \frac{\partial [C]}{\partial t} = k[A][B] + \phi C_{,in} - \phi ...
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How does the temperature of HCl affect the reaction rate of HCl & Mg reaction?

I'm Olivia. I'm experimenting with HCl and Mg. My purpose is to find the change of the reaction rate while I increase the temperature of HCi. According to the study, when I increase the temperature of ...
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Titanium reaction with Sodium Percarbonate solution

I've been reading about a process for darkening Titanium using Sodium Percarbonate that consists of the following steps: Prepare Sodium Percarbonate solution 1:5 with boiling water Soak titanium ...
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Reaction between iron oxides to form magnetite

In the notes of a course it is indicated that the reaction of formation of magnetite from iron oxides can only take place if the partial pressure of oxygen is higher than 1 nanobar. $\ce{FeO}$ + $\ce{...
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Reaction of Grignard reagents with phosphoric acid derivatives

The use of Grignard reagents that people are most familiar with is the production of tertiary alcohols by reaction with a suitable carbonyl compound, whether it be an ester, ketone, or aldehyde. As I ...
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Is this a valid interpretation of the Mean relative speed between two (Maxwell-Boltzmann) species?

In textbooks, the collision frequency $Z_{ab}$ is always given as something like: $$Z_{ab} = n_an_b\sigma_{ab} \Bigg(\frac{8 k T}{\pi \mu}\Bigg)^{1/2}= n_an_b\sigma_{ab} \bar{C}_{rel}$$ where the ...
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Are there any pathways that can change a solution to all colors of the rainbow?

The challenge's like this. Suppose you have a beaker containing a liquid of transparent or any color. You add some drops of another liquid and the beaker turns into, say, red after some swishing. You ...
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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-...
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What determines the coefficient B in the Bell-Evans-Polyani equation?

From the Bell Evans Polanyi principle, $E_a = A + B \Delta H$. How is the $B$ coefficient determined? This is my thinking: For exothermic reactions (where the transition state resembles reactants more ...
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Parameters of NaHCO3 + citric acid + H2O + NaCl mixture potentially impacting functional efficacy in pest control application?

I have been searching for infomation on this application, but have some specific questions that I have not seen directly addressed in the Google/Stack Exchange posts I've come across thus far; below ...
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Formation of Aniline from Chlorobenzene

My textbook says: When chlorobenzene is treated with aqueous ammonia at 473K under a pressure of 60 atmospheres in presence of cuprous oxide or cuprous chloride, aniline is formed. Notice the ...
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Temperature control and side reactions in PPAA (T3P) couplings

In a lot of procedures for amide couplings (acid + amine) using PPAA, the coupling agent is added to a cooled solution of the acid, amine, and a non-nucleophilic base such as DIPEA. This is done even ...
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Succinic anhydride esterification won't go forward

I'm trying to react succinic anhydride with a decyl alcohol to produce mono-decyl succinate. Literature and Google searches suggest that the monoesterification should proceed without catalyst. However ...
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CSTR reaction cooling jacket - Transfer Functions

I have a CSTR where an irreversible exothermic liquid reaction takes place. Coolant is flowing in the jacket of the tank to regulate the temperature of the fluid in the reactor and control in this way ...
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What are some convenient examples of so-called dissolved organic matter (DOM) for lab work?

Background, I have come across a chemical reaction system, occurring in nature, that apparently involves the presence of dissolved organic matter (in a catalytic role). My research returns, for ...
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Why use Stork enamine alkylation?

I recently learned about the Stork enamine alkylation method of adding electrophiles to the beta carboxyl position on a molecule. But I can't seem to find out why a direct synthesis is not possible (...
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1 answer
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Good Hess's Law experiment [closed]

I am doing an Internal Assessment for my IB chemistry class, and I want to do something on Hess's Law, and I'll be doing it simulation based, using this website. With the solutions and equipment on ...
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2 answers
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Real life examples of chemical reactions [closed]

For my upcoming lab report, I want to look at exactly how a simple variable, such as heat or surface area, affects a reaction. But I'm having trouble finding a reaction to test this on, as my results ...
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Chemical reaction of radicals with different multiplicity

I am studying the chemical reaction of radicals by computational chemistry software. I just want to know what is the rules for multiplicity. I have two radicals for which, the ground state of one is a ...
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1 answer
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What is the opposite of a catalyst and examples? [duplicate]

I remember a while ago I heard of something that slowed reactions and was effectively the opposite of a catalyst. What is this called? Also would appreciate examples and an explanation of their uses ...
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What does spontaneous mean in term of forward and reverse reactions?

I just learnt about Gibb's Free Energy and was thinking about an exothermic reaction with a negative change in entropy. This means that the reaction would occur at low temperatures. But that means ...
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-2 votes
1 answer
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Reaction Of Carbonic Acid With NaCl [duplicate]

I was just wondering if it was possible for anyone to specify what reaction conditions are required for the reaction between $\ce{H2CO3}$ (Carbonic Acid) and $\ce{NaCl}$ (Sodium chloride)? Does this ...
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1 vote
2 answers
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How can I have iron powder without a fast reaction with oxygen? [closed]

I've seen this video in which fine iron powder reacts immediately with oxygen when exposed to the air, turning into rust. Now, will this reaction always occur with iron powder? Or is there something ...
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1 answer
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Formation of Acetal from Hemiacetal?

In the reaction mechanism of formation of Acetal from Hemiacetal, why doesn't H+ attack the Oxygen of OR Group instead of the OH? Since O in OR group has +I effect from two alkyl groups, shouldn't it ...
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1 answer
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How to measure the speed in a catalized reaction? [closed]

What is cheaper? Set up a constant time of reaction and measure the concentration of the products or; Set up a constant quantity of reactants and, with an indicator, measure the time until the ...
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-1 votes
2 answers
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Why does Sodium Bicarb. Reduce Combustion Rate? [closed]

In many common solid-propellant model rocket engines, Sodium Bicarbonate, $\ce{NaHCO3}$, is used to predictably regulate/limit the rate of combustion of the fuel. My questions are as follows: What is ...
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5 votes
1 answer
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Decarboxylation of THCA during CO2 Extraction of Cannabis

We have a strange problem. We are performing CO2 extraction on cannabis and we are seeing considerable decarboxylation of THCA to THC. We have high quality temperature sensors at the heat exchangers, ...
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Is the activation energy always inversely proportional to the reaction rate?

When I obtained the activation energy using the Arrhenius equation for a 10-minute glowstick (rapid, rigorous reaction), it was almost 4 times that of a 12-hour glowstick (slow, mild reaction). ...
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0 votes
1 answer
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Are there reactions operated at high temperature at industrial level? [closed]

Temperature is an important parameter when you deal with a chemical reaction, first of all $\Delta G$ and $\Delta G^\circ$ depend on temperature, and as a consequence the spontaneity of a reaction ...
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Controlling rate of endothermic reaction

In an experiment, I have two endothermic reactions taking place simultaneously: $$ \begin{align} \ce{A + B &-> C + D}\tag{1}\\ \ce{E + G &-> Z + F}\tag{2} \end{align} $$ $\ce{C}$ and $\...
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3 votes
1 answer
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Why does phenolphthalein form in this reaction?

This reaction (http://orgsyn.org/demo.aspx?prep=CV1P0476) gives quinizarin as the major product in about 70% yield. However, when the same reaction is conducted with phenol insteas of p-chlorophenol, ...
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Increasing temperature in system of dynamic equilibrium

According to the article Summary of Le Chatelier's Principle on dynamicscience.com.au, for the process $$\ce{N2(g) + 3 H2(g) <=> 2 NH3(g)}\quad ΔH = \pu{-92 kJ/mol}$$ the forward reaction is ...
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-1 votes
1 answer
906 views

Do secondary alcohols react faster than primary alcohols or is it the other around? [closed]

My questions is that do secondary alcohols react faster than primary alcohols or is it the other around? This for the oxidation of the alcohol to a ketone or an aldehyde. This reaction is with KMnO4 ...
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0 votes
2 answers
222 views

Catalyst that combines oxygen and hydrogen

Are there any known catalysts that can combine hydrogen and oxygen into water? Does this type of reaction have a name? Trying to search for information, it seems to be all about splitting hydrogen ...
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4 votes
0 answers
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CuAAC "Click" reaction giving inconsistent results

I apologize in advance for the large amount of text and thank all those who take the time to read it. The "Click" reaction after Fokin and Sharpless is known to achieve high yields without long ...
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Chloride Process TiO2 recovery

In the chloride process (the process used to create titanium oxide from titanium ore), how is TiO2 collected? What prevents the TiO2 from building up on the walls of the reactor chamber? It's my ...
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-1 votes
1 answer
65 views

Is it possible to predict release of acid fumes in certain acid reactions? [closed]

Upon mixing both acids, the reaction between Formic Acid and Sulfuric Acid, besides producing Carbon Monoxide and Water, releases a certain amount of acid fumes. Does anyone know if the fumes, in ...
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1 vote
0 answers
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What are the chemical principles behind paper/ink deterioration over time and how do I prevent them? [duplicate]

I have been working on a time capsule for the past few months, in which I decided to not include any electronics (ie: no USB). I am done writing the content of the capsule, but I have some concerns ...
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Catalysts to accelerate foamy polyurethane reaction

This is the reaction that I am referring to: https://www.youtube.com/watch?v=EoRUSo0BWC0 I am interested in finding catalysts to accelerate this fun chemistry demonstration. I have heard that some ...
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8 votes
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Role of pH in azo C-coupling reaction, continued

In the question, "What is the role of pH in azo coupling reaction of diazonium with phenol and aniline?" asked by @DhrubaBanerjee and answered by @Klaus-DieterWarzecha, I find several ends ...
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-1 votes
2 answers
112 views

Can equilibrium be calculated at any time of an acid base reaction and still be the same? [closed]

Should the equilibrium constant $K$ be calculated at the end of an acid-base titration or can we calculate it in the middle of the titration for example? If so, will the calculated equilibrium ...
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4 votes
1 answer
556 views

Why do we use Δ to mean heating?

To express heating, we usually use $\Delta$ over reaction arrows like \begin{align} \ce{CaCO3 ->[\Delta] CaO +O2}. \end{align} Why do we use $\Delta$ to mean heating during chemical reactions? I ...
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4 votes
1 answer
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Which reaction rate formula is suited for diatomic molecules in a plasma?

I am an experimental physicist, so I unfortunately do not know much about chemistry except the basics. For my current study, I am investigating diatomic molecule formation in plasma. These diatomic ...
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0 votes
0 answers
257 views

Why mixture turns brown upon heating, during esterification with H2SO4?

In the lab I was synthesising an ester with sulphuric acid as a catalyst. However the mixture turned brown and my teacher said I had burnt the acid, but what does this actually mean?
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2 votes
1 answer
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What are standard controllers for automatic pH control?

My background in control theory comes from electrical engineering (robots, motors, etc.) and I want to build a control system for automatic pH control. Can I directly apply my knowledge from ...
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