The study of rates of chemical processes.

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Kinetic and Thermodynamic Stability

My prof noted that if the two components of any ionic compound undergo a large extent reaction with each other, then the substance CANNOT exist as a pure substance. For example, consider ammonium ...
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Formation Constants; Lewis Acidity

I still distinctly remember reading about how Lewis acidity/basicity was characterized using kinetics. The reason given was that because formation constants are so large, these reactions are not ...
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What are the units for m in the average kinetic energy formula?

For the equation $E_k=\frac{1}{2}mu^2$ what does the $m$ variable represent? I would say mass but the textbook does not say explicitly that it is anything.
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What is reactivity really, and can it be quantified?

I understand the concept of a reactive species on a sort of vague and intuitive level: a reactive species is one that has lots of reactions that it can participate in. These tend to have large kinetic ...
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Plot of Arrhenius Equation with temperature

I saw the plot of Arrhenius Equation Here It is a concave upwards graph, but acc to the equation $k= A e^\frac{-E_a}{RT},$ it is evident that the graph is of the form $y= e^\frac{-1}{x}.$ I ...
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Why are solids and liquids not included in the equilibrium constant? What about in a reaction rate calculation?

Take for instance the rection $$\ce{H2(g) + I2(s) -> 2HI(g)}$$ The equilibrium constant would not include the solid $\ce{I2}$, but why is this? I have read that its concentration is a constant, ...
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Finding overall order of reaction

Recently I've been going through an exercise of Chemical Kinetics and Nuclear Chemistry and right now I am stuck to one. Question was previously asked in JEE(Advanced)-2013. The question says, In ...
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29 views

Activation Energy in Acid/Base reactions

For simple acid/base reactions - i.e. those involving inorganic compounds - does activation energy ever play in reactions? Or can we ignore kinetics entirely and just consider thermodynamic factors ...
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Does this activation of carbonyls usually involve a SN1 or a SN2?

The process I have seen in class to activate a carbonyl function is acetalisation. One of the steps involved is the following : So I was wondering, is that a $\ce{S_{N}1}$ or a $\ce{S_{N}2}$ ? ...
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Furan and maleic anhydride: Why is the major product exo?

For most Diels-Alder reactions, the product is endo because there are favorable interactions between the newly forming pi-bond and the electron withdrawing groups of the dienophile. Why is the ...
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26 views

Rate law of the iodine clock reaction

I am dealing with the iodine clock reaction, which has the half-reactions: $$\begin{align}&\ce{H_2O_2 (aq) + 2I^- (aq) \to I_2 (s) + 2 OH^- (aq)} & (\text{slow}) \\ &\ce{I_2 (s) + ...
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Variation of Arrhenius equation with concentration

In the Arrhenius equation do Arrhenius constant and activation energy depend on concentration ? (Their units do)
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Should binding constants be unitless when deriving fractional occupancy equations from reactions?

It is known that binding (aka association) constants are in fact unitless, as has been discussed here already. However, I'm not a chemist and am confused about when one should or should not use units ...
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Will heating diatomic oxygen enough break the O=O bonds?

The bond enthalpy associated with a O=O double bond is equal to 495kJ/mol. Does that mean that adding enough kinetic energy in the form of heat will eventually cause the bonds to break and create ...
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Question regarding 1st order kinetics

We know for a $1^{\text{st}}$ order reaction $ A \rightarrow B$, we write the rate law as: Rate = $k[A]^{1}$, and the integrated law for this is $ \ln (\frac{A}{A-x}) = kt$. So by studying this ...
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Magical reaction tanks

I would be interested to know people's opinion on the following matter. Background Often, when the far-from equilibrium behaviour of a chemical reaction system is analysed mathematically (in papers ...
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120 views

Relationship between magnitudes of forward and reverse kinetic rate constants

Consider the reversible unimolecular reaction: $A \overset{k_{1}}{\underset{k_{2}}{\rightleftharpoons}} B$ We know that the forward reaction is often considerably more thermodynamically favourable ...
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Global warming kinetics

A rule of thumb in chemistry is that a reaction doubles in rate for every $10^\circ C$ increase in temperature. Considering the impact of a $10^\circ C$ increase in global temperature, would the same ...
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827 views

Why does potassium react the most vigorously with water?

Link to exam Which metal reacts most vigorously with water? (A) Ca (B) K (C) Mg (D) Na The given answer is B and the reasoning is that is is the most electropositive since it the furthest ...
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Which Ion is most kinetically inert?

im currently self teaching myself some chemistry, the textbook I am using is around degree level. I have come across a question though that has really stumped me: Which ion is most kinetically inert? ...
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Multiplication of the reaction and Equilibrium constant

$$\begin{align}\ce{2A + 2B &-> 2C }\\ \ce{A + B &-> C}\end{align}$$ Why does the equilibrium constant change? And why the rate of the first reaction square the rate of the second? I ...
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Rate Constant Units and Eyring Equation

Rearranging the Eyring equation leads to the following: $$ ∆^\ddagger S^\circ = R \ln{\frac{k \times h}{{k_B}{T}}}+\frac{∆^\ddagger H^\circ}{T} $$ where k is the rate constant, h is the Planck ...
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Is the end of a cigarette on fire when lit?

Is the end of a cigarette on fire when it is lit? Or is it smoldering? Is there a chemical difference between the two?
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Simple Kinetics Clarification

I just wanted to check my understanding of this. Given the reaction, $$ (1) \; \ce{A->B} $$ the corresponding rate law is $ v=k[A] $ Also consider $$ (2) \; \ce{A <=> B} $$ with forward ...
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Deriving goldman equation

So I've been trying to follow the derivation of the Goldman-Hodgkin-Katz equation on Wikipedia (https://en.wikipedia.org/w/index.php?title=Goldman_equation ) - I can follow it through after it sets up ...
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51 views

Can an excessive reactant amount result in a longer reaction time?

I am performing an experiment with DTZA and Ferrate. After a point of increasing the DTZA concentration too much the Ferrate takes longer (lower reaction rate) to react with the DTZA. Is this ...
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Why can't the molecularity be determined from the rate law?

Basically can someone explain why the molecularity cannot be determined from the rate law?
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The effect of concentration on the rate of a homogenous reaction

I have to do an experiment where I will find out what the influence of the concentration on the reactionspeed of a homogenous reaction is. We are asked to create 2 solutions, respectively A and B: ...
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Decreasing rate of reaction between $\ce{I2(s)}$ and $\ce{H2(g)}$?

Which change will decrease the rate of the reaction between $\ce{I2(s)}$ and $\ce{H2(g)}$? (A) Increasing the partial pressure of $\ce{H2(g)}$ (B) Adding the $\ce{I2(s)}$ as one piece ...
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103 views

Rate and order confusion

I just learned about rate and order... I just want to confirm if these three ideas are correct: If the first elementary step is the slow step, will the stoichiometric coefficients of the reactants ...
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112 views

Changes in which factors affect both the rate and the rate constant of a first order reaction?

Changes in which factors affect both the rate and the rate constant of a first order reaction? I. temperature II. concentration (A) I only (B) II only (C) Both I and II (D) ...
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349 views

What are some good examples of rate equations for a math class?

I'm a mathematician who's currently teaching a course on differential equations. Though I don't know much about chemistry, I like to include examples from chemistry in my course, and I prefer for the ...
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rate determination by 1H NMR spectroscopy

Currently I investigate a reaction where a starting material A reacts with an excess of thiophenol B towards products C and D. As shown by recurrent TLC analysis of the reaction, the formation of D ...
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Reaction Rate Limiting Reaction

Why exactly does the slowest reaction limit the instantaneous rate of a reaction even if the faster processes come after? Theoretically, if the products of the slow reaction are required for the fast ...
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Specific Case of the Rate law

My textbook says that for a chemical reaction with two reactants, $\ce{A}$ and $\ce{B}$ with equation $\ce{aA + bB -> Products}$, where $a$ and $b$ are coefficients, the general rate law is: ...
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Deriving the Rate Law

How do you derive the formula for the general rate law? Where does it come from, and why? I know how to use them and get information from them, but not why they are correct. Do they follow from the ...
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Reaction Order Greater than 1

What is the chemistry behind why reactions of order >1 exist? And what role does the number of activated complexes formed have in determining reaction rate?
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Temperature in the Maxwell-Boltzmann Distribution

I am attempting to generate the probability for the specific speed of a molecule using the Maxwell-Boltzmann distribution, but I cannot decide on which temperature I should use in the equation. For ...
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429 views

Calculate the specific rate constant (k)

The question is: Suppose we found that the reaction of Red#3 with bleach is 1st order in hypochlorite. The observed rate constant ($k_{obs}$) for one of the trials was measured to be $0.00400 ...
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456 views

Finding the average rate of consumption

The question is: If $2.0 \cdot 10^{-4}$ moles of dye in $50$ mL of solution is consumed in 188 seconds, what is the average rate of consumption of dye in $\text{mol}/\text{L}\cdot \text{s}$? I am not ...
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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 ...
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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 ...
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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 H2O2 lab, in which we decompose H2O2 with KI as a catalyst. I've gotten this data so far: ...
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55 views

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 $\text{kJ mol}^{-1}$. It says that from this value, it was calculated that cyclohexane undergoes ...
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461 views

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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Question concerning 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 ...
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How to estimate reaction products of competitive binding?

I have an two reactions, $A + C \rightleftharpoons AC$ $B + C \rightleftharpoons BC$ I'd like to estimate relative steady state proportions $\frac{[BC]_{SS}}{[AC]_{SS}+[BC]_{SS}}$ and ...
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Hill constant cooperativity

Is there an expression for calculating $K_d$ for a cooperative system (using the Hill constant)? I can't find one online and there was none given in my lectures, only a rearranged formula for the ...
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Is there a general consensus on the causes of the $\alpha$-effect?

There have been various explanations posited for the $\alpha$-effect. It is currently in the list of unsolved problems in chemistry on Wikipedia, but, due to a lack of references to that effect, I'm ...