All Questions
Tagged with equilibrium kinetics
115
questions
3
votes
1
answer
56
views
Iminium formation rate between formaldehyde and secondary amine
Given the significantly more favored hydrate of formaldehyde in the presence of water under neutral conditions, can we say that this is the slow step in iminium formation? Would removing water/working ...
3
votes
1
answer
65
views
How can a Michaelis–Menten formalism be used when enzyme concentration isn't constant?
I understand that $V_\mathrm{max} = k_3[\ce{E}]_0$ in ordinary Michaelis–Menten (MM) kinetics. According to the lecture notes provided by my university (I don't believe they are available online), ...
-1
votes
3
answers
107
views
How is it even possible that vapour pressure of liquid and vapour of solid are equal at freezing point? [duplicate]
My text book states The freezing point is defined as "the temperature at which the vapor pressure of the substance in its liquid phase is equal to its vapor pressure in the solid phase" Also ...
1
vote
1
answer
85
views
Derivation of general binding equation (macromolecule with multiple binding sites)
So the last days I'm stuck at trying to solve the an equation - but I just can't (see the screenshot below.
So the idea is that you have a receptor or enzyme with multiple binding sites for a Ligand (...
0
votes
1
answer
63
views
Reaction kinetics exercise for hydrogen iodide synthesis
The rate constant for the reaction of hydrogen with iodine is $\pu{2.45E-4 M-1 s-1}$ at 302 °C and $\pu{0.905 M-1 s-1}$ at 508 °C.
a. calculate the activation energy and Arrhenius preexponential ...
2
votes
1
answer
97
views
Why Michaelis Menten Assumption of equilibrium is necessary to integrate rate of ES production
I read in my textbook that the assumptions of equilibrium and of steady state used by Michaelis and Menten were simplifying assumptions intended to make the following equation one that can be ...
3
votes
0
answers
310
views
Equilibrium constant of the formation of ferric thiocyanate
I was reading the paper Relaxation Kinetics of Ferric Thiocyanate (Goodall et. al, 1972) and I came across a passage which read
$\space$ Reaction (1) is the simplest representation of the equilibrium ...
3
votes
0
answers
309
views
Derivation of the Van 't Hoff equation
I was reading the paper Relaxation Kinetics of Ferric Thiocyanate (Goodall et. al, 1972) and I came across the passage
Reaction (1) is the simplest representation of the equilibrium between ferric ...
0
votes
1
answer
187
views
Non-elementary reactions: Relationship between kinetic and equilibrium constant
As far as I understand, the equation for a kinetic equilibrium is always the same, and is given by:
$$K = \frac{\text{concentration of products}^{p}} {\text{concentration of reactants}^{r}}$$
Where $p$...
0
votes
0
answers
88
views
Why can we use stoichiometric coefficients in the equilibrium-constant expression? [duplicate]
I just studied the chapter on chemical kinetics on Coursera, wherein I was repeatedly admonished not to use the stoichiometric coefficients in the rate law formula. I was told that this formula has to ...
-3
votes
1
answer
131
views
What if kc=1 will reactants concentration equals to product concentration [closed]
I read a book, it says if kc=1 it mean reactant concentration equals to product concentration at equilibrium. But I'm wondering that in kc expression we dont just use concentration of an element we ...
2
votes
3
answers
336
views
Change of equilibrium constant with respect to temperature
Suppose we have an arbitrary chemical reaction $A+B\rightleftharpoons 2C+D$ and its equilibrium constant at two temperatures $T_{1},T_{2}$ are $k_{1},k_{2}$. We can relate them as
$$\log\frac{k_{2}}{...
1
vote
0
answers
33
views
How do metal hydrides behave in a non-hydrogen closed system?
I am curious about the fundamentals of metal hydrides and how adsorption/desorption works in non-hydrogen systems. My understanding is that the atom ratio M/Hx of the metal hydride is a function of ...
5
votes
2
answers
909
views
Effect of inert gas on the rate of reaction
Is there a general effect on the rate of reaction of a dynamic equilibrium when an inert gas is introduced at a constant volume? I know that the position of equilibrium won't change, but much like a ...
-1
votes
2
answers
112
views
Confused about underlying reasoning behind reaction quotient/equilibrium constant
I am a high school student taking AP Chemistry. In the unit on chemical equilibrium, there is much emphasis placed on calculating reaction quotients and equilibrium constants using this method: $$aA + ...
0
votes
0
answers
67
views
Strange behavior of equilibrium constant when most of the components are solids / pure liquids
Consider the reaction $\alpha A(g) + \beta B(s) +\gamma C(s) +\cdots \rightleftharpoons \delta D(s)+\epsilon E(s)+\cdots $, so the chemical equilibrium constant should be $\dfrac{1}{[A]^\alpha}$, ...
1
vote
0
answers
131
views
On Le Chatelier's principle
According to my textbook,
Increasing the concentration of the reactants increases the rate of forward reaction only to reestablish equilibrium (Le Chatelier's principle)
But doesn't that also ...
3
votes
0
answers
108
views
Equilibrium concentrations of CO and Cl2 by dissociation of phosgene
I am working through a problem set from MIT's open courseware course Principles of Chemical Science.
The question is:
Phosgene $\ce{(COCl2)}$ is a chemical warfare agent that decomposes by the ...
0
votes
2
answers
100
views
chemical equilibrium and activity
Here is a graph of equilibrium coeff in various salt concentrations in water.
Lets take the example $\ce{BaSO4}$.
Now as we are increasing the salt concentration in water, the following reaction is ...
1
vote
1
answer
80
views
What is the difference between a single displacement reaction and a two competing reaction system?
For example, consider the single-displacement reaction
$$\ce{AB + C <=> BC + A}$$
My question is then if writing this reaction as the system
\begin{gather}
\ce{AB <=> A + B} \\
\ce{B + C &...
2
votes
1
answer
59
views
Rate law for thermolysis at temperatures well above the decomposition temperature
If the temperature is higher than the decomposition temperature, are thermal decomposition reactions reversible? For example, which of the following schemes would be more appropriate for temperatures ...
0
votes
0
answers
87
views
Why don't we take activities in the rate law?
I am slightly confused by the fact that concentrations and not activities are taken in the rate law which is different to equilibrium and seems to lead to a discrepancy. For example, for the reaction $...
0
votes
1
answer
58
views
Are there any well documented reactions with "persistent" intermediates
I'm a biology and/or math person, not a chemistry person. I have only taken the standard sequence of undergraduate courses up to organic chemistry, and that was some time ago, so please excuse (and ...
2
votes
1
answer
459
views
Combining two reactions in equilibrium with same reactants but different products: What would be the new K?
If I have the reactions :
A(g) ⇌ B(g) K1
A(g) ⇌ C(g) K2
Am I able to add the equations like done in Hess's law despite nothing canceling out? And if I can do so, is the new equilibrium ...
0
votes
1
answer
1k
views
How to relate equilibrium constant and equilibrium conversion?
For the following gas phase reaction:
$$ A\leftrightarrow B $$
The concentration equilibrium constant ($K_c$) can be expressed as:
$$ K_c = \frac{c_B}{c_A} = \frac{\frac{F_B}{\vartheta}}{\frac{F_A}{\...
1
vote
1
answer
314
views
How does the rate equation account for solids and liquids?
The question is long because I wanted to include the whole thought process.
Given the hypothetical reaction:
$$\ce{ A(s) + B(aq) <=> C(aq) + D(aq)}$$
One would obtain the equilibrium constant:
$$...
2
votes
0
answers
41
views
Do decomposition potentials change during electrolysis?
I was just wondering if decomposition potentials actually change during electrolysis. For example, if we reversed the Daniell cell reaction so that copper is oxidized, the half cell reactions would be:...
8
votes
4
answers
833
views
Deriving kinetic equations for reversible reactions
Problem
Given the reaction $\ce{A <=>[$k_\mathrm f$][$k_\mathrm b$] B}$ with rate constants $k_\mathrm f = \pu{4E-2 s-1}$ and $k_\mathrm b = \pu{10^{-2} s-1}$. Initially, $\pu{2 mol}$ of $\ce{A}...
0
votes
1
answer
119
views
How is the equilibrium expression (law of mass action) related to the rate law? [duplicate]
Every chemistry textbook I've read will have a chapter on the rate law. It will say something like, given a reaction $a\text{A} + b\text{B} \rightarrow c\text{C} + d\text{D}$, the rate law (for the ...
0
votes
0
answers
24
views
Why is the concentration of gases denoted in form of partial pressure? [duplicate]
In most of the chemical laws of chemistry involving concentration of products or reactants like equilibrium constant, reaction quotient, Henry's law, Nernst equation etc, I often see a similar note ...
2
votes
1
answer
1k
views
The effect of dilution on the rate of a system in equilibrium
I'm attempting to answer a question from my textbook, however the answer that the textbook provides doesn't make sense to me.
The question:
Laura, a VCE chemistry student, loves graphs and wanted to ...
-1
votes
1
answer
507
views
Sequential reaction in equilibrium
Derive an equation for the steady-state rate of the sequence of reactions $$\ce{A <=> B <=> C <=> D}$$ with $[\ce{A}]$ maintained at a fixed value and the product $\ce{D}$ removed as ...
4
votes
0
answers
74
views
Decomposition of Hydrogen Peroxide Catalysed by Potassium Iodide in Basic Solution
As part of my high school project, I had to measure the initial rate of decomposition of hydrogen peroxide catalysed by potassium iodide at different pHs. At higher pHs (alkaline conditions), I found ...
1
vote
1
answer
522
views
Equilibrium constant of a reaction whose order of forward and reverse reaction is not same
Suppose, a reaction is like,
$$\ce{aA + bB <=> cC + dD}$$
and that A, B, C, D all are gas.
Now it is known that:
$$K_c = \dfrac{[A]^a[B]^b}{[C]^c[D]^d}$$
Now if the forward reaction is second ...
-3
votes
1
answer
46
views
How does it affect the equilibrium expression if the concentration of any component remains the same?
I am a high school student and I am very confused in Equilibrium expression, My confusion is that "Why we don't write concentration of solids and pure liquids in equilibrium expression?" ...
1
vote
2
answers
220
views
Can reversible reactions proceed by different mechanisms in the forward and reverse directions? [closed]
It seems odd to me that this would be the case, but it also seems odd that it wouldn't.
Imagine a mechanism for a (forward) reaction that includes a slow reversible step and a fast irreversible step:
...
1
vote
1
answer
59
views
how to derive equilibrium concentrations from initial conditions for mass action reactions?
I am reading a tutorial on biochemical reactions and mass action kinetics (https://www.math.utah.edu/~keener/books/control.pdf, pp. 1-2) and would like to derive an analytic solution to confirm ...
-3
votes
1
answer
104
views
Wiki’s explanation of the rate of chemical reaction [closed]
Could you please help me understand the Wiki’s explanation of the rate of chemical reaction?
It says: the rate of the chemical reaction is directly proportional to the product of the activities or ...
5
votes
1
answer
403
views
Common Ion Effect - Ionic Equilibrium
Question
In which of the aqueous solutions of the following, dissociation of $\ce{NH4OH}$ will be minimum?
A) $\ce{NaOH}$
B) $\ce{H2O}$
C) $\ce{NH4Cl}$
D) $\ce{NaCl}$
My Thoughts
My book says that ...
4
votes
1
answer
1k
views
Equilibrium constant for heterogeneous equilibria having aqueous as well as gaseous reactants
Suppose we have a heterogenous equilibrium :
$$\ce{A(aq) +B(aq) <=> C(g) +D(aq)}$$
Which equilibrium constant is used here?
Both pressure and concentration terms are there. So, according to me, ...
1
vote
0
answers
153
views
How can I analytically calculate the rate of thermal decomposition of calcium carbonate?
I am a first-time poster on Chemistry StackExchange, and not much of a chemist.
I'm trying to determine the rate of thermal decomposition (in mol/s) of calcium carbonate ($\ce{CaCO3}$) at various ...
1
vote
1
answer
604
views
Why does a first order reaction only depend on the concentration of a single reactant?
I am new to kinetics so please explain it from basic, If there is a reaction -
$$\ce{A + B + C -> D}$$
In first order reaction rate is given by-
$\mathrm R = k[\mathrm A]$ or $\mathrm R = k[\...
2
votes
0
answers
1k
views
What is the recipe for the Belousov-Zhabotinsky reaction for correct simulation with the Oregonator model? [closed]
For a school project I'm trying to model the Oregonator and perform some experiments with the Belousov-Zhabotinsky reaction. Like predicting the reaction and the swings in concentrations. For that it ...
3
votes
2
answers
737
views
How do we know a reaction is in equilibrium?
In teaching secondary science equilibrium, how can we actually show there is a backwards reaction occurring during equilibrium rather than no reaction. A lot of equilibrium experiments involve ...
2
votes
1
answer
588
views
Chemical equilibrium — why multiplication, rather than addition? [duplicate]
Why do we multiply (and not take the sum) the concentration of products and reactants when more than one entity is present in either side and rise the power to the coefficient term?
Suppose either
$$...
2
votes
2
answers
103
views
Is equilibrium constant at a given temperature derived from Gibbs free energy of reaction valid for doing simple kinetic modelling?
I intend to do a kinetic study of simple alcohol catalytic dehydrogenation reactions in the gas phase. I want to start with simple power law kinetics using $K_\mathrm{eq}$ to account for the ...
1
vote
1
answer
181
views
How to derive the steady-state solution for simple two-step reaction with differential equations? [closed]
Consider this simple two step reaction, a variant of a Michaelis-Menten type of problem, where $\ce{A}$ and $\ce{B}$ reversibly bind to make $\ce{AB}$, and $\ce{AB}$ and $\ce{C}$ reversibly bind to ...
2
votes
2
answers
586
views
Chaos in chemical reactions
I recently read about Chaos Theory and was wondering if a chemical reaction results in or shows characteristics of chaos (I found a few examples of such reactions here)
Chaos theory concerns ...
1
vote
1
answer
104
views
What does it mean for chemical reaction network to be in equilibrium?
What does being in "equilibrium" mean for a set of chemical reactions? If we have some number $n$ of $\ce{A}$ molecules and $m$ of $\ce{B},$ and the following reaction where $\ce{A}$ and $\ce{B}$ can ...
6
votes
1
answer
635
views
Equilibrium constant for a solid-solid equilibrium
Suppose there are two equations:
$$
\begin{align}
\ce{A(s) &<=> B(g) + C(s)} &\quad &K_1 \tag{R1}\\
\ce{B(g) &<=> D(s) + E(s)} &\quad &K_2 \tag{R2}
\end{align}$$
...