Questions tagged [reaction-order]

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36 views

Calculate concentration of product after time passed

If I have two parallel reactions: A --> P$1$ (k$_1$ = $0.00010$ s$^{-1}$) A --> P$2$ (k$_2$ = $0.00050$ s$^{-1}$) and know that the initial concentration of A is $0.0417$ M. How can I ...
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25 views

Calculating the concentration of reactants and products in parallel reactions after a time t

A substance A reacts with a solvent B to form an intermediate product IP. The reaction is bimolecular. The conc. of the solvent is constant at $12$M. IP can then react to form the two products P$1$ ...
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52 views

Determining reaction order from absorbance

A reaction is initiated in a solution which contained a dissolved component. The transmittance was measured at $\pu{240 nm}$ in a $\pu{2.54 cm}$ long cell. At $t = 0$ the transmittance was $1$. $\...
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Why is a pseudo first order reaction also called pseudounimolecular reaction?

Molecularity is defined as the number of reacting species taking part in an elementary reaction . So for example if we take ester hydrolysis then as the concentration of acid/ alkali does not get ...
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0answers
43 views

Plotting second order reaction with different reactants

In a laser flash photolysis experiment, $\ce{C6H5NH2}$ $(C_0 = \pu{60 \mu M})$ is oxidize to its corresponding radical cations. There are three possible reaction pathways for the formation of the ...
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1answer
77 views

How do the terms in a rate law relate to effectiveness and number of collisions of reactants?

In chemical kinetics, we use rate law to find the instantaneous rate of reaction. Let us consider a simple reaction $$\ce{aA + bB -> products}$$ where the rate law is $$\mathrm{rate} = k[\ce{A}]^a[\...
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41 views

How to graph a second order reaction with two different reactants

In a laser flash photolysis experiment, $\ce{C6H5NH2}$ $(C_0 = \pu{60 \mu M})$ is oxidized to the corresponding radical cation. The disappearance of radical cation is monitored spectrophotometrically ...
3
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1answer
73 views

First or second order reaction

I have that $100$ mM of K$_3$Fe(CN)$_6$ is dissolved in equimolar of the organic ion (which I assume is HCN). In the solution Fe(CN)$_6$$^{3-}$ reacts to form Fe(CN)$_6$$^{4-}$. The formation of Fe(CN)...
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1answer
226 views

Is the rate of a zero order reaction always independent of the concentration of its reactants?

Consider the following reaction : $\ce{A + B}$ $\rightarrow$ $\ce{Products}$ where order of the reaction w.r.t. $\ce{A}$ is $-1$ and order of the reaction w.r.t. $\ce{B}$ is $+1$. So, overall order of ...
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1answer
154 views

Determine reaction order and reaction rate

In a solution of $\ce{Fe^3+}$ the concentration was measured to be: $$\begin{array}{c|c} t/\pu{min} & \ce{[Fe^3+]}/\pu{\mu M} \\ \hline 10\ & 238\\ 20 & 227\\ 40\ & 206\\ 60\ & ...
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1answer
65 views

Are the orders of reactants with respect to a reaction different for different starting concentrations?

If the reaction is repeated with $\pu{2 M}$ ethyl iodide the pyridine concentration decreases as shown below. Give the rate law of the reaction in terms of pyridine and ethyl iodide. Explain your ...
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4answers
781 views

Formula for rate constant for the first order reaction

My lecturer mentioned that the formula for the rate constant $k$ for the first order reaction is $$k = \frac{2.0303}{t_{1/2}}\,\log\frac{[\ce{A}]_0}{[\ce{A}]_{t_{1/2}} - [\ce{A}]_0},\tag{1}$$ where $...
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1answer
50 views

In reaction equations, why are j and k sometimes capitalized to J and K?

From 'Leighton relationship' on Wikipedia: through the following mechanism:[2] ($J_1$) $$\ce{NO2 + h\nu (\lambda < 420 nm) → NO + O (^3P)}$$ ($k_2$) $$\ce{O (^3P) + O2 + M → O3 + M}$$ ($k_3$) $$\ce{...
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1answer
257 views

Arrange in the order of their reactivity of SN2 reaction

Here in case of (1) it is more favorable towards SN1 reaction as it will create benzyl carbocation which is very stable. (2) Here it is more favorable towards SN1 as it is first of all allyl ...
2
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1answer
100 views

Relationship between molecularity and the reaction order

Should the molecularity be equal or less than the reaction order? Consider the reaction: $$\ce{H2(g) + I2(g) → 2 HI(g)}$$ If we consider the mechanism of this multi-step reaction, the molecularity is ...
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0answers
28 views

Is order defined for a reaction which does not follow power law dependence?

As per my knowledge , order of a reaction is the sum of exponents of all the terms in rate law of the reaction But reaction which do not follow power law dependence , for example , formation of HBr , ...
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40 views

Parallel reactions for one product

For me it is clear how I could solved the kinetic of a parallel reaction like this But, how can I solve if this would be the case: Thanks in advance!
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54 views

Is this statement valid for reactions of all orders? [duplicate]

My textbook (not an international standard) states that for the first order reactions only The quantity of reactant remaining after $n$ half lives is $$A_n = \frac{A_0}{2^n},$$ where $A_0$ is the ...
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2answers
75 views

Inconsistency in Elementary Bi-Molecular Reaction Rate Expressions

Assume the following bi-molecular reaction is elementary as written with rate constant $k_\mathrm{f}$: $$\ce{A + A -> P}$$ This review, suggests to express the rate in terms of the production of ...
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0answers
34 views

Catalysts and activation energy

Do catalysts increase rate of reaction only by decreasing activation energy? Or can they affect the Arrhenius factor or reaction orders? Like if one catalyst is more effective at increasing rate of ...
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3answers
178 views

Balancing reactions algebraic method limitations [duplicate]

How do I balance this reaction using the algebraic method? Seems that the equation can't be solved. How do I balance such reaction and does the algebraic method has limitations and wont work for ...
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3answers
190 views

Second order reaction with different reactants

In a laser photolysis reaction $\ce{C6H5NH2}$ $(C_0 = \pu{60 µM})$ is oxidized to its radical cation. The disappearance of the cation can follow three pathways: (1) Dimerzing of the cation, (2) ...
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1answer
89 views

Can iodine replace other halogen as well?

While reading about halogen family I encountered the reaction: $$\ce{NaClO3 + I2 -> NaIO3 + Cl2}$$ I know that that the oxidizing tendency of halogens decreases down the group, so I think that the ...
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1answer
826 views

Find order of reaction 2A → B + C

Derive the integrated rate expression for a reaction of type: $$\ce{2A -> B + C}$$ I first need to determine the order of the reaction in order to find integrated rate law of that particular order....
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1answer
200 views

How is the Rate law of a reaction measured?

What is the Rate law of the reaction below? $$\ce{4 HBr + O2 -> 2 H2O + 2 Br2}$$ How do we approach finding the rate law of a reaction? Can this be found out only through experiments?