All Questions
Tagged with rate-equation kinetics
45
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Why isn't the rate of an elementary reaction expressed in activity?
Why don't chemists use $r_\ce{X}=\frac{\text{d}a_\ce{X}}{\text{d}t}$ where $a_\ce{X}$ is the chemical activity of species $\ce{X}$ and corresponding rate law for elementary reactions as $r=ka_1^{\...
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when to use exponents, or multiply by constants in the equation of the rate involving $k$ and concentrations?
More specifically, I do not understand
rate of consuming $\ce{I}=2 k_2[\mathrm{I}]^2+2 k_3\left[\mathrm{H}_2\right][\mathrm{I}]^2$
Why is the concentration of $"\ce{I}"$ squared from $"2 \cdot k_3 \...
user146933
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Does increasing temperature increase the rate of gaseous reactions?
In chemical kinetics there is a generalised statement that the rate of reaction is dependent upon
the concentration of reactants (except for zero order/complex reactions)
temperature
catalyst
surface ...
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-2
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77
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Is it possible to calculate the theoretical rate of reaction?
I am conducting an experiment where I will be changing concentration (0.2 mol/dm3, 0.4 mol/dm3, 0.6 mol/dm3, 0.8 mol/dm3, 1.0 mol/dm3) and seeing how that affects the rate of reaction for a reaction ...
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83
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HCN reactor design
For my diploma work, I should design a hydrogen cyanide (HCN) producing reactor.
I found that for the BMA process, overall
$$\ce{CH4 + NH3 -> HCN + 3 H2 \quad{} \Delta{}H_r = \pu{251 kJ / mol} }$$
...
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59
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A first order gaseous reaction - getting the rate law
There is a specific example cited in our NCERT Class 12 textbook, to find out the rate law equation for a general gaseous reaction, $$\ce{A->B + C}$$
It describes the entire procedure as shown:
...
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Is my derivation for the reaction orders of a single-step reaction valid?
Recently in my chemistry class I learned about reaction orders. For some reaction $\ce{r_1A1}+\ce{r_2A2}+\dots+\ce{r_nA_n}\rightarrow\ce{B}$, $m_1,\dots{,m_n}$ are the orders of that reaction. The ...
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97
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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 ...
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What is the physical significance of the frequency factor in the Arrhenius equation?
As the title says, I am wondering what the physical significance of the frequency/pre-exponential factor in the Arrhenius equation. My idea of it is that:
If the units of $E_a$ are energy per molecule,...
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91
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What are the differences between the different Rate Equations?
I currently am about to finish general chem 2 so my knowledge is still basic.
There are different kinetics and rate equations and im not quite sure I know the differences.
Breaking rate of a reactant:...
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2
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153
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Solving for Partial Pressure given first-order decomposition
From my GenChem practice exam:
Consider the following reaction:
$\ce{C4H8 (g) → 2C2H4 (g)}$
The first-order decomposition of cyclobutane to two molecules of
ethene has a rate constant of $\ce{9.20\...
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1
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1
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560
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Calculating rate constant for reaction between potassium permanganate and oxalic acid
I'm writing a lab report investigating the effects of temperature on the rate constant in the reaction between potassium permanganate and oxalic acid. For my practical I've measured the time of colour ...
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96
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Reaction rate derivation: amount of substance vs concentration [closed]
Let's say you have the reaction
$$A + B \; \rightarrow \; C.$$
I would like to understand why $\frac{\mathrm{d}[C]}{\mathrm{d}t}$ is proportional to $[A][B]$. I can see why
$$\frac{\mathrm{d}n_C}{\...
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1
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113
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Reversible monomolecular reaction with two reverse rates
I think this is a simple problem but my kinetics are terrible and I was hoping for some assistance following up on the work of a previous student. I'm open to any form of assistance and I hope this ...
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55
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Dependence of rate on the nature of reactants and other factors
Consider a reaction
$$\ce{aA + bB -> cC + dD}$$ whose reactants are given by A and B and the products are C and D.
The rate of this reaction is given by $$\frac{dx}{dt} = -\frac{d[\ce{A}]}{adt}= -\...
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