The study of rates and steps (mechanisms) of chemical processes.

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Coconut oil vs Olive oil: Spray dynamics

Ps: If this would better fit Physics then please move it there or let me know. I put it here based on fact that viscosity and colloids were part of chemistry curriculum 10/15 yrs back in school. Let'...
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chemical kinetics of TG analaysis [on hold]

Can some one help me figure out how to determine TG analysis Excel data for calculation activation energy?
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39 views

Convert mass-based reaction rate equation to mole-basis

I have the following kinetic scheme describing the conversion of wood to tar and gas products. Wood is considered to be pine with a density of $\rho_\mathrm{w} = 540\; \mathrm{kg/m^3}$, tar is ...
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115 views

Explain why alumina-containing zeolites possess chemically active surfaces

I think zeolites possess acid sites that are catalytically active in many hydrocarbon reactions. The pore system only allows molecules that are small enough to enter, hence it affects the selectivity ...
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Calculate the rate of decomposition of H2O2 at 25 °C when [H2O2] is exactly 10.0 mmol/L

I'm really confused? $$\ce{2H2O2 -> 2H2O + O2}$$ $$\begin{array}{ccc}\hline \text{Experiment no.} & c(\ce{H2O2}) & \text{rate} \\ \hline 1 & 14.45 & 3.35 \times 10^{-3}\\ 2 & ...
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22 views

Why do coefficients become exponents in the speed equation when dealing with elementary reactions

In school, while studying chemical kinetics, we were learning about the speed law and equation for different chemical reactions. We learned that in general, the exponents of the concentration of ...
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Which class of polymerization reactions reaches high conversion under one second?

Are there polymerization reactions that can reach high conversion very fast, say under 1 sec? i.e. to polymerize "immediately"?
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Parameter effects on kinetics of esterification for bio-diesel production

I want to discuss the effect of parameters on the kinetics of esterification for bio-diesel production. In esterification process, temperature effect and molar ration are two important parameters. ...
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65 views

How the equation that describes evolution of alkyl nitrates has been derived?

I was reading this paper, Bertman, S. B., J. M. Roberts, D. D. Parrish, M. P. Buhr, P. D. Goldan, W. C. Kuster, F. C. Fehsenfeld, S. A. Montzka, and H. Westberg (1995), Evolution of alkyl nitrates ...
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Mechanism of thyroid hormone synthesis: iodation and free radical formation

In the synthesis of thyroid hormone, what part of the thyroid peroxidase hormone is specifically responsible for abstracting the free radicals from the aromatic side chains in the iodated tyrosine ...
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30 views

Is there are any universal methods or software for reaction rate modelling?

In software like DWSIM are used databanks which contains enthalpy and entropy at 298 K and more other information about chemicals. This software can create a steady-state system, where showed state of ...
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A rate problem;Determining the order

My attempt I believe the answer should be second order reaction looking at the units of k But I think the question is to be solved with the help of integrated laws I tried using it to check ...
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Rate problem: Determining the order

In the presence of an acid, the initial concentration of cane sugar was reduced from 0.20 to 0.10 molar in 5 hours and from 0.2 to 0.05 molar in 10 hours. What is the order of the reaction My attempt ...
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92 views

Problem on chemical kinetics

Is the question asking the concentration when the system has reached its half life Can use the half life formula? The attempt at a solution I used the rate law which I equated to the definition of ...
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49 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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29 views

Latent Heat and Kinetic Energy

The kinetic theory says that temperature is the measure of the average kinetic energy. That would mean then : The temperature rises with the rise in kinetic energy. We know that when matter changes ...
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35 views

Elementary Reactions

I'm studying some kinetics of reactions and in particular the topic analyzed is the bromidic acid production starting from $\ce{H2}$ and $\ce{Br2}$. The reaction $$\ce{H2 + Br2 -> 2HBr}$$ can be ...
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24 views

Does the Hydrogen/Chlorine reaction in light proceed instantaneously?

When a mixture of Hydrogen and Chlorine is exposed to short wavelength light it reacts explosively. Does the reaction happen simultaneously through the bulk of the mixture?
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potential profile in kinetics and spontaneity in reactions

We usually think of the criterion of spontaneity of a reaction as the change of Gibbs energy. By Clausius inequality, one of various forms of the 2nd law, we know that $ \mathrm{d}S-\frac{\mathrm{d}H}...
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39 views

Deriving kinetic equations for a complex reaction system

I have a system of protein reactions that I've derived differential equations for the kinetics of. I'm using them to run simulations to fit the rate parameters, but the simulations at present are ...
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61 views

The effect of reactant concentration on when equilibrium is established

Take the equation $$\ce{A(g) <=> B(g)}$$ where the reaction is first order with respect to A. The rate law is thus $$\frac{\mathrm d[\ce{A}]}{\mathrm dt}=-k[\ce{A}]$$ Say you run the reaction, ...
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Effect of His-tag on enzyme activity

In my biochemistry laboratory class, I designed an experiment to study the effect of a His-tag on enzyme activity. First, I measured the activity of the His-tagged enzyme. Then, I cut off the His-tag (...
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42 views

How does changing the concentrations of intermediate products/reactants change the rate law?

A = CH2(CN)2 B = CH(CN)2- C = BrCH(CN)2 The rate law above is derived from applying the steady state approximation. I am trying to work out how to modify the rate law to accomodate the following ...
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Factoring in kinetic equations [duplicate]

The mechanism for the linear chain reaction of H2+Br2 -> HBr is: If we presume steady state for the chain carrier Br*, we recieve this equation: My question is in regards to the '2' factor marked ...
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In Statistical Transition State Theory, why is $[AB^{\ddagger}_f] = [AB^{\ddagger}_r]$?

For example on Wikipedia (https://en.wikipedia.org/wiki/Transition_state_theory), and also in my lecture notes, it is assumed that for a reaction $A+B\rightleftharpoons AB^{\ddagger} \...
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How can we integrate Maxwell-Boltzmann's distribution to obtain the expression for activation energy?

I tried integrating the expression first by replacing the v^2 terms by E. It turned out to be the integral of (sqrt.E * e^(-E/kT)). I tried integrating it by parts but the exponential term will ...
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“Reacts most vigorously”

What is meaning of "Reacts most Vigorously" Is it related to Thermodynamic aspect or Kinetic? Like for example if we are given that A reacts with C more vigorously than B reacts with C. Then which ...
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29 views

Which reactions are more temperature sensitive, the ones with higher Ea or the ones with lower Ea and why?

I wasn't able to find much useful content on googling it, however on doing the math i came to a conclusion that the ones with higher Ea are more sensitive to increase in temperature. But why is it so? ...
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Halving the electrolyte concentrations of a voltaic cell

Say you have a standard voltaic cell with $Q=1$. The concentrations of both the electrolytes are at 1.0 M. If you halve the concentrations in both to 0.5 M, $Q$ still equals 1 and $E_{cell}=Eº_{cell}$....
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Is the rate determining step the step with the largest Ea?

I've seen some controversy on this question while doing a brief search. For example, this SE answer quotes Wikipedia and says that the RDS is the step with the largest $E_a$. However, this UC Davis ...
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Looking for solubility kinetics of zinc chloride hydroxide monohydrate

$\ce{Zn5(OH)8Cl2·H2O}$ is a crystalline solid insoluble in water. Often used as nutritional supplement. Preparation and chemistry of zinc chloride hydroxide monohydrate is known. I am looking for some ...
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363 views

How does an energy input actually change a molecule?

I'm reading an online biochemistry textbook for fun, and a question that has bothered me on chemistry before popped up again. The question here is not specific for the chemical process described, but ...
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42 views

Experimentally finding order of a reaction

For the reaction of bromocresol green and bleach, I was supposed to conduct an experiment to find the order of the reaction with respect to bleach. To do this, I used a fixed amount of bromocresol ...
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Binding Energy and Enzyme Rate

I was preparing for the Canadian Chemistry Olympiad and I ran into the following question on one of the past exams: If enzyme A binds to the substrate 25 times stronger than enzyme B, what is the ...
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How to calculate the rate of micelle formation in a soap solution?

How can I design and conduct an experiment to calculate the rate of micelle formation in a soap solution? This would relate to the topic of chemical kinetics which we are currently doing in class.
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114 views

What does a fractional order of reaction mean for the mechanism?

I'm doing a high school/sixth form college investigation of the kinetics between magnesium ribbon and hydrochloric acid. I have obtained a rate order was 1.5 w.r.t [H+] and hence the rate equation ...
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kinetics of adsorption of hydrogen on nickel

What is the order of reaction involving adsorption of Hydrogen on Nickel? The reaction does not depend on the concentration of hydrogen (does it?) but depends on the surface area of nickel. More the ...
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Why is 2H2O2 -> 2H2O + O2 a first order reaction?

My book says that the reaction $\ce{2H_2O_2 -> 2H_2O + O_2}$ is a first order reaction and that it's rate equation is $\ce{k[H_2O_2][I^{-}]}$. However i don't see why that would be first order? ...
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Measuring reaction rates when reactants and products both have (different) molar extinctions at the chosen wavelenghth

In my Biochem labs we would always measure the consumption of NADH, and they always noted that it was useful that NAD+ had essentially no absorbance at 340 nm, which allowed us to directly relate ...
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Bimolecular and Isomerization reactions

Is it possible to describe a reaction of the $$\ce{A + B <=> AB}$$ exactly using the solution of an isomerization reaction? $$\ce{A <=> B}$$ I just can not figure it out the equations ...
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49 views

How to calculate the rate of reaction of Sodium and Chlorine

$$\ce{2Na(s) + Cl2(g) -> 2NaCl(s)}$$ How exactly do you calculate the reaction rate of the following equation? Since reaction rate is usually calculated in moles per $\rm dm^3$ per second (M/...
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Factors affecting mass of a gas-evolving reaction mixture over time

Excess magnesium was added to a beaker of aqueous hydrochloric acid on a balance. A graph of the mass of the beaker and contents was plotted against time (line 1). What change in the experiment ...
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Questions about Collision Theory [closed]

The collision theory states that, for a reaction to occur, particles must collide with each other. How about a reaction that has only 1 reactant, for instance decomposition of water / hydrogen ...
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Kinetics: Rate and Order of Reaction

I have run a reaction of 0.020M $\small\ce{FeCl3}$ and 0.020M $\small\ce{KI}$. The solvent of $\small\ce{FeCl3}$ was $\small\ce{HCl}$, but had no effect on the reaction and, therefore, has a reaction ...
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27 views

finding the concentration of B

At the intersection point of two curves nA-->mB, the concentration of B can be given as:(assume the reaction to be 1st order) can someone explain me how to go about it? I have no clue how to go ...
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Do we use activities or concentrations in the rate expression?

The equilibrium constant of a reaction is a dimensionless quantity due to the fact that we use activities instead of concentrations(in moles/liter). But, in the rate expression for a reaction, do we ...
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Shape of the blood CO2 dissociation curve

What equation determines the shape of the blood $\ce{CO2}$ dissociation curve? I know that since it factors all possible forms of $\ce{CO2}$ carriage, there are a bunch of factors (e.g. Henry's law, ...
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Arterial blood CO2 content, division and partial pressure

My lecturer cites Boron and Boulpaep's Medical Physiology (2nd edition) for the following claims: the total $\ce{CO2}$ content of arterial blood is $26.4$ mmol/L or $48\%$ v/v (not sure if these ...