A catalyst is a substance that increases the rate of a reaction without modifying the overall standard Gibbs energy change in the reaction; the process is called catalysis. This tag is appropriate for reactions, their mechanisms, their kinetics, when catalysts of any kind are involved.

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Why do catalysts have limited turnover numbers in practice?

I quote the Wikipedia page definition for Turnover number: In other chemical fields, such as organometallic catalysis, turnover number (abbreviated TON) has a different meaning: the number of ...
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how to find out the velocity constant of ethyl acetate catalysed by acetic acid practically in lab using reagents and equioments? [closed]

how to find out the velocity constant of ethyl acetate catalyzed by acetic acid using practical data in laboratory and how to gain and proceed with the readings ?
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Why are hydrogenation reactions exothermic?

I learnt that all reactions that yield hydrogen are endothermic (such has reforming) and reactions, that use up hydrogen, are exothermic (FCC cracking, hydrogenation, etc.). But why is this so? I know ...
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Catalytic activity of metals [duplicate]

What are the electronic features of the metals that make act as catalysts ?
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38 views

Alchohol absorbent & water repellent

Is there any solid material that is absorbent of only alcohol and not water? I am trying to look for possible ways to separate alcohol from water without the use heating and distillation process.
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Curing of polyester resin that did not reach top exothermic temperature

When working with polyester resins for fiberglass or geloat, there are times where the thickness of the resin on the substrate is not sufficient to get a strong exothermic reaction and achieving a ...
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Reasons which explain why the efficiency of a reaction increases as the average rate decreases?

Reasons which explain why the efficiency of a reaction increases as the average rate decreases? in other words, why does a slow chemical reaction is more effective than quick ones? I done an ...
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Stereochemistry of hydrogenation with Raney nickel

If I react the following with Raney nickel and $\ce{H2}$, $\hspace{65 mm}$ then I am getting a meso compound, as the $\ce{H-}$ anion will have anti addition, right? One $\ce{H}$ will attack on right ...
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Why can't Pd/C and H2 reduce both the alkene and carbonyl portions of α,β-unsaturated carbonyls?

Why is it that the major product of the reduction of chalcones the ketone and not the monoalcohol? In other words, Why isn't the major product a benzyl alcohol? From what I understand, catalytic ...
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How do copper(II) ions catalyse the reaction between iodide ions and persulfat ions?

Do copper (II) ions form dative bonds with water molecules and then a substitution reaction occurs when iodide ions and persulfate ions are added? How does copper catalyse the reaction between iodide ...
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Can TiO2 be considered a catalyst in DSSC?

For solar cells - either dye-sensitized solar cell (DSSC) or photoelectrochemical cell (PEC)-, can $\ce{TiO2}$ be considered as a photocatalyst as it is what absorbs UV and creates holes/electron ...
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Are Organic Solvents used in Addition Reactions catalysts?

Say for example you are performing a halogenation reaction with dichloromethane (DCM) as the solvent: ethylene + chlorine $\stackrel{DCM}\longrightarrow$ 1,2-dichloroethane I have 2 questions: Is ...
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What role does H2SO4 play in the following titration

The titration is between Oxalic acid and Potassium Permanganate, with H2SO4 added to Oxalic acid. My question is what role other than a dehydrating agent and maybe catalysing does the H2SO4 play in ...
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Why does the $V_{\mathrm{max}}$ of an enzyme not change with competitive inhibition? Shouldn't it decrease since there are fewer active sites?

My textbook states that $V_{\mathrm{max}}$ doesn't change for competitive inhibition. This makes no sense to me, since decreasing the amount of active sites available should lower the rate of an ...
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27 views

Calculation of concentration of component at catalyst surface

I am struggling a bit with an external diffusion problem. I am trying to calculate the concentration at the surface (as well as surface reaction rate) and would like some help or guidance. Here is ...
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Could the net equations for burning hexene be used as a means of energy source?

$6\ce{CO_2} + 6\ce{H_2O}\xrightarrow{some\;catalyst}9\ce O_2 + \ce{C_6H_{12}}$ $\ce{C_6H_{12}} + 6\ce O_2\to 6\ce{CO_2} + 6\ce H_2$ $6\ce H_2 + 3\ce O_2\to 6\ce{H_2O}$ At one point, I had made a ...
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Dependence of the rate of a catalysed reaction on substrate concentration?

In my answer to this question: Master equation for catalyst and substrate binding?. I made the assumption along the following lines: If we have a substrate concentration $[S]$ then the rate of ...
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How to inhibit Mn2+ autocatalysis in the oxalate-permanganate reaction?

It is well known that permanganate in acidic solution can oxidize oxalate ions (or oxalic acid). The reaction produces $\ce{Mn^2+}$, which catalyzes this very reaction. $$\ce{2MnO4^- + 16H^+ + ...
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Does oxygen catalyze the decomposition of sucrose?

When a bottle of sports drink that contained sucrose is opened, is it expected that the sucrose contained therein will split into its constituents (fructose and glucose) more rapidly than it will via ...
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41 views

Palladium catalyst

Recently I found the following question by sam: I'm supposed to produce dry and pure oxygen using the decomposition of hydrogen peroxide with a manganese dioxide catalyst. $$\ce{2H2O2(aq) -> ...
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Where can I find simple reaction rate formula for catalytic partial oxidation of methane? [closed]

I have already found equations here but they are too complex (heterogeneous reaction). I need a simplified (and so approximated, limited to such case, but this doesn't matter...) network of equations ...
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How might ammonia be created in this mechanochemical reaction?

Can mechanical agitation catalyze reactions? It appears so (thanks to Mithoron for the pointer!). We observed the following: We were using 10-micron hBN powder to impact-plate copper bearings (e.g., ...
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why platinum/palladium are such a good catalyst?

Platinum and palladium are great catalysts. At the same time, other metals of the same family are not. What are the atomic level reasons for this?
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896 views

Why is more of a catalyst added, when it is not consumed?

… catalysis, the acceleration of chemical reactions by substances not consumed in the reactions themselves—substances known as catalysts. (Source) Now as I’ve understood, to keep a reaction ...
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Effect of Catalysis on Reaction Rate in elementary Reaction

I understand that there are many different catalytic mechanisms that suggest different ways of accounting for the effect of a catalyst on reaction rate. My question is: Given a termolecular ...
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212 views

Does a catalyst increase atom economy?

Somebody I know insists that the use of a catalyst increases the atom economy. They did chemistry at school, and were told that a catalyst increases the atom economy. He pointed me to several past ...
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The Propinquity Effect

I am currently in the process of studying enzyme catalysis and am struggling to get to grips with this concept. As far as I understand, the propinquity effect allows substrates to bind with enzymes in ...
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Grubbs, Wittig & Hydroboration reactions and Woodward-Hoffmann rules

The mechanism of the olefine metathesis using Grubbs' catalyst consists of [2+2] cycloadditions and reverse cycloadditions. The Wittig reaction, too. How are they in accordance with the ...
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Basis set in the computational software “Gaussian-03” for studying adsorption of a hydrogen atom on a carbon paste electrode dropcasted with Pt-CNT

What is the basis set in the computational software "Gaussian-03" that can be used to study the interaction of $\ce{H}$-atom with $\ce{Pt-CNT}$ dropcasted electrode? How can we study the energy ...
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jury-rigging an automotive catalytic converter for use in the Ostwald Process?

Would it be feasible to jury-rig an automotive catalytic converter for use in the Ostwald Process for the production of Nitric Acid? Given reasonable safety precautions, would it be safe enough to be ...
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2answers
858 views

When an enzyme is diluted with water, what is slowing down the rate of reaction?

I'm specifically talking about the decomposition of hydrogen peroxide by bovine catalase. The number of catalase molecule obviously doesn't change, so there's the same number of catalase molecule ...
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Does the catalyst alter the Potential energy Surface?

Catalyst provides alternative pathway to the reactants. Does it also mean that the potential energy surface is altered?
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compression set of tin catalyzed silicone better than platinum?

Platinum silicone is more dimensionaly stable, it shrinks less when it cures. However, i just need silicone which has good compression set (small change by compression), and perhaps, once they are ...
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Electrode for methanol

Could you advice an electrode for electrophoretic deposition in methanol which won't spoil methanol and also wont be spoiled by methanol. I googled a bit and found that 1 copper, platinum and gold are ...
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Lewis Acid Catalysts [closed]

I am studying for the International Chemistry Olympiad and some of questions involve synthesis of complicated organic compounds and i have no idea how to do them. The setting of the questions is ...
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How are catalysts discovered for a particular reaction?

I want to understand how are catalysts discovered for a particular chemical reactions say for example $\ce{Fe,~Mo}$ for Haber's Process reaction of $\ce{N2}$ & $\ce{H2}$. Reactions as examples ...
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A misunderstanding about the energy profile of reactions with a catalyst involved

All of us are aware of the importance of the catalysts in bio-chemistry. For a high school learner like me, catalysts ,and therefore, enzymes play a bridge-like role that connect high school bio to ...
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1answer
350 views

How does a Catalytic Poison reduce a catalysts activity

How does A catalytic poison reduce the activity of a catalyst, such as palladium used in hydrogenation of alkenes or any other such catalyst.
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Does product induced poisoning qualify as a rate limiting step?

I have a question about whether a particular situation qualifies as a rate limiting step. I have a catalyst that under normal conditions gets poisoned when products accumulate on the catalyst surface. ...
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1answer
339 views

What is a sacrificial agent?

I came across this reading a journal article. Here I have the context: Here we report for the first time the synthesis of $\ce{TiO2}$ NPs on a layered $\ce{MoS2}$/graphene (MG) hybrid for use in ...
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1answer
396 views

Differences between Urushibara nickel and Raney nickel

The Wikipedia article about Urushibara nickel catalyst is rather short and vague. What is the mechanism for its preparation, and furthermore, in what sense does it differ from Raney nickel (i.e. when ...
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1answer
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How do zeolites catalyse the cracking of hydrocarbons?

Been learning about catalytic cracking of long chain hydrocarbons into shorter chain hydrocarbons, in which the catalyst zeolite is used so that the temperatures needed for the cracking are much lower ...
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What are the specific disadvantages of using a bio-catalyst (called Lipolase) in the synthesis of the drug pregabalin?

I am studying the synthesis of a drug pregabalin, for which both chemical and bio-catalysts are used. Using a biocatalyst is way better than chemical route, as explained here. In fact, The invention ...
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What is the type of dependence of the rate of reaction on the amount of catalyst?

I have performed an experiment where I had some test tubes with the reagents and different amounts of catalyst. I started the reactions and measured the time they took. Then I calculated the rate of ...
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1answer
171 views

Why it is not yet possible to produce ethanol selectively in the Fischer Tropsch reaction?

The Fischer Tropsch reaction between $\ce{CO}$ and $\ce{H2}$ has the potential to give a wide range of products. However by judicious choice of catalytic metal it is possible to produce $\ce{CH4}$, ...
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1answer
465 views

How does salt and water promote corrosion?

I was always wondering why iron only rusts when it gets wet. I know that for example aluminium oxidises on its own on regular basis. I also heard many complains that salt used to remove snow from ...
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Is there a catalyst that will reduce an alcohol to an alkane?

There are many reduction methods of going from an alcohol to an alkane: http://www.transtutors.com/chemistry-homework-help/hydrocarbons/reduction-of-alcohols.aspx And there are catalytic methods of ...
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Photoelectrochemical (PEC) water splitting

I'm starting to prepare for my research project on photoelectrochemical (PEC) splitting of water into H and O using (F doped) titanium dioxide as the photoanode. I've been unsuccessfully searching in ...
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Why do we need acid when making acetone peroxide?

Acetone peroxide is a very dangerous explosive, easily detonated by mild heating, friction or shock. It appears in the form of small white crystals. This compound forms from the mixture of hydrogen ...
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Which has higher rate of hydrogenation- methyl propene or trans-2-butene?

I know that cis-2-butene has a higher rate of hydrogenation than both of these due to steric reasons, but here both of these compounds have same steric hindrance. So, when they come in contact with ...