Skip to main content

Questions tagged [reaction-order]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
0 votes
0 answers
60 views

Why is reaction rate proportional to the order of reactants? [duplicate]

I know that for some elementary reaction $m\text{A}+n\text{B}\rightarrow\text{C}$, the rate of reaction is given by $-\frac{\text{dA}}{\text{dt}}=k[\text{A}]^m[\text{B}]^n$. Now if we consider the ...
Chitraksh Pandey's user avatar
1 vote
0 answers
60 views

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 ...
Eyeballer's user avatar
-2 votes
3 answers
153 views

Why is concentration never zero for zero order reactions? [closed]

By formula of zero order reaction:- $$C_t=C_o-kt$$ The concentration should be zero at $t=C_0/k$. But in some books and websites I saw that graph between concentration and time don't touch the X-axis. ...
NOTE Book's user avatar
3 votes
1 answer
270 views

Why is the decomposition of gas on a metal surface at high pressure considered a 0 order reaction?

My textbook says that when ammonia decomposes on a platinum surface at high pressure, the reaction is 0-order. This is because at high pressures, the metal surface gets saturated with ammonia ...
Harjot Dhillon's user avatar
1 vote
1 answer
213 views

How to interpret gas chromatography results?

I am having trouble interpreting gas chromatography (GC) results for the production of ethyl acetate from acetic acid and ethanol. I am trying to find the reaction order from these results, as well as ...
pulsewidth's user avatar
-1 votes
2 answers
83 views

How to write a rate expression when one reactant is not soluble?

For a chemistry experiment, I would like to determine the rate expression for the reaction between zinc and hydrochloric acid. Given that zinc is not soluble in the water, would I use a "false&...
Guest's user avatar
  • 19
-1 votes
2 answers
142 views

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\...
Mailbox's user avatar
  • 269
0 votes
1 answer
231 views

Order of reaction with and without the presence of catalyst

When ethene reacts with hydrogen to give ethane in the presence of Ni, the order of the reaction is 2, if I am not wrong, please correct me if I am. But if we remove the catalyst, and simply allow ...
SchrodingerCat2023's user avatar
1 vote
0 answers
225 views

Can the overall order of a reaction ever be strictly less than $1$?

In A-level chemistry we are taught that: To every reaction: $$\sum_{i=1}^n c_iA_i\to\sum_{j=1}^m d_jB_j$$There is a rate equation: $$r=\kappa[A_1]^{\alpha_1}[A_2]^{\alpha_2}\cdots[A_n]^{\alpha_n}$$...
FShrike's user avatar
  • 223
0 votes
0 answers
147 views

Temperature dependence of order of reaction

In my textbook, it is given that the order of a reaction can change with temperature and pressure, but examples are not given. One possible explanation for this is that the rates of complex reactions ...
Yoogi Kovendhan's user avatar
4 votes
2 answers
2k views

Why can't the half-life be determined in a reaction with more than one reactant?

We have a second order irreversible reaction with 2 reactants (A and B, order 1 for both) so that the initial concentrations are different. I've read that the half-life doesn't make sense in this ...
Jorge Bonifaz's user avatar
3 votes
1 answer
1k views

Negative or fractional order of reaction

Let $\ce{A}$ be the reactant and $\ce{P}$ the product at the imaginary elementary reaction $\ce{A->P}$. Could it possibly have a net total order of $-1?$ $$-\frac{\mathrm d[\ce{A}]}{\mathrm dt} = k[...
Jorge Bonifaz's user avatar
-1 votes
2 answers
104 views

How to rationalize independence of half-life time from the initial concentration for the first order reaction?

Using the rate expression for the first order kinetics and expressing the half-life time, it can be proven the half-life time $t_\frac 1 2$ of the first order reaction is independent of its initial ...
Sudhagar's user avatar
  • 131
-2 votes
1 answer
183 views

Does E1 mechanism always imply first order reaction?

Oxford University Press, Okuyama & Maskill: Organic Chemistry — Chapter 13: Multiple Choice Questions, Question 1: Which of the following statements regarding the E1 mechanism is wrong? a) ...
MS04's user avatar
  • 7
-2 votes
1 answer
335 views

Confusion regarding order of reaction

The following points are given in my textbook about order and molecularity:- (i) Order of a reaction is an experimental quantity. It can be zero and even a fraction but molecularity cannot be zero or ...
user avatar
0 votes
1 answer
709 views

Calculate rate constant of second order reaction and pseudo first order reaction

The reaction A + B -> Prod follows the second order kinetics. In an experiment, you initially have ten times as much B as A. The concentration of A varies with time according to the following data: ...
katara 's user avatar
  • 1,095
0 votes
0 answers
82 views

Calculating ionic strength at different concentrations

Zn$^{2+}$ reacts with a molecule, B, in a solution at several different concentrations of NaCl. Determine the charge of the biomolecule and k$_0$ (second order) ​​(assume that Zn$^{2+}$ does not ...
katara 's user avatar
  • 1,095
0 votes
1 answer
2k views

Why is it that first order reactions never end? [duplicate]

I'm studying chemical kinetics in high school. We are studying Integrated Rate Equation of first order reactions - their derivations and graphs. Our teacher showed us a graph of: Concentration of ...
sysgrammer's user avatar
2 votes
1 answer
78 views

Determine reaction order of Cyclopentadiene

Reaction: $\ce{2 C5H6 -> C10H12}$ For this reaction it is stated that $\pu{0.609 M}$ cyclopentadiene was formed in an ethanol solution. When the solution was heated $(\pu{40 ^\circ C})$ and ...
katara 's user avatar
  • 1,095
0 votes
0 answers
33 views

Can two 1st order reactants in an overall 2nd order reaction have different rates?

I've recently done a saponification reaction of ethyl acetate with sodium hydroxide and used the initial rates method to find the order of reaction. (I change the concentration of one reactant and ...
Alan Liu's user avatar
-3 votes
1 answer
70 views

(Beginner Question) Reaction Word Problems [closed]

I am having trouble understanding how to create equations which can then be balanced. For example, if I am told that a freshly scraped piece of aluminum reacts with oxygen from the air to form a ...
bleuofblue's user avatar
-1 votes
1 answer
51 views

What are some three+ stage cyclical reactions that only go one direction?

I was imagining the origins of life and supposed that "humans are just a bunch of cyclical chemical reactions in a coat." Which made me wonder, what sort of cyclical chemical reactions ...
Seph Reed's user avatar
  • 101
1 vote
2 answers
287 views

Finding the reaction order from a given plot of chemical kinetics

What will be the order of the reaction for a chemical change having $\log t_{1/2}$ VS $\log a$ Where $a=$ Initial concentration of reactant and $t_{1/2} =$ Half Life? 0 order 1st order 2nd order None ...
Shashank's user avatar
3 votes
0 answers
45 views

The Mechanism of Termolecular Reactions

How does a termolecular elementary reaction happen under the law of mass action? My physical chemistry textbook only says details about bimolecular and unimolecular reactions with collision theory. I ...
Ofreo's user avatar
  • 31
1 vote
0 answers
40 views

Are there any pathways that can change a solution to all colors of the rainbow?

The challenge's like this. Suppose you have a beaker containing a liquid of transparent or any color. You add some drops of another liquid and the beaker turns into, say, red after some swishing. You ...
longtry's user avatar
  • 365
0 votes
1 answer
534 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 ...
katara 's user avatar
  • 1,095
1 vote
0 answers
224 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 $1$. $\...
katara 's user avatar
  • 1,095
2 votes
0 answers
54 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 ...
katara 's user avatar
  • 1,095
0 votes
1 answer
120 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[\...
user avatar
1 vote
0 answers
55 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 ...
katara 's user avatar
  • 1,095
3 votes
1 answer
160 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)...
katara 's user avatar
  • 1,095
3 votes
2 answers
1k 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 ...
Pranita Baruah 1's user avatar
4 votes
1 answer
674 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\ & ...
katara 's user avatar
  • 1,095
2 votes
1 answer
103 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 ...
user avatar
5 votes
4 answers
8k 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 $...
Muhammad's user avatar
  • 185
0 votes
1 answer
91 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{...
Kurt Hikes's user avatar
  • 1,813
1 vote
1 answer
1k 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 ...
Soham Chatterjee's user avatar
4 votes
1 answer
448 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 ...
Achuthan Yogarajah's user avatar
0 votes
0 answers
87 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!
CaIsFR's user avatar
  • 1
0 votes
0 answers
56 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 ...
Sahil's user avatar
  • 113
0 votes
2 answers
106 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 ...
chr218's user avatar
  • 13
0 votes
0 answers
42 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 ...
John's user avatar
  • 47
0 votes
3 answers
520 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 ...
user94356's user avatar
4 votes
3 answers
368 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) ...
katara 's user avatar
  • 1,095
-2 votes
1 answer
155 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 ...
user89505's user avatar
-1 votes
1 answer
3k 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....
peaceHoper's user avatar
2 votes
1 answer
218 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?
Maggi Iggam's user avatar