MY CART (5)

ITEM
DETAILS
MRP
DISCOUNT
FINAL PRICE
Total Price:

There are no items in this cart.
Continue Shopping
                   what is the difference between first order kinetics and pseudo first order kinetics. Is adsorption kinetics is different. Because Iam working in Dye removal studies by algal biomass, which order kinetics should I follow.
                   

3 years ago

Share

Answers : (2)

                                        

Dear Rashmi V,


The main difference between a First Order Reaction & a Pseudo First Order reaction is that the Pseudo first order eaction is a reaction that should actually happen by some higher order(higher than 1) but occurs by first order beacuse the concentration of one reactant used is very high & another reactant used is very low ...


The concentration of the reactant which is very low can be negleted & thus the concentration of the reactant which has higher concentration is alone taken !


This makes the reaction follow a first order kinetics rather than some higher order.This is Pseudo First order reaction !


 


Hope you understood now..


All the Best & Good Luck !


Please approve my answer if you liked it by clicking on "Yes" given below...!!Smile


 

3 years ago
                                        

Pseudo First Order Reaction

A  and  B  react to produce  P:



If the initial concentration of the reactant  A  is much larger than the concentration of  B,   the concentration of  A  will not change appreciably during the course of the reaction The concentration of the reactant in excess will remain almost constant. Thus the rate's dependence on  B  can be isolated and the rate law can be written


Equation  (1)  represents the differential form of the rate law. Integration of this equation and evaluation of the integration constant  C  produces the corresponding integrated law.

Substituting  [ B ]  =  c  into equation  (1)  yields


Integrating equation  (2)  gives: The constant of integration  C  can be evaluated by using boundary conditions. At  t  =  0,   the concentration of  B  is  co.

Therefore Accordingly, equation  (3)  can be rewritten as follows:
If the decrease in concentration of  B  is followed by photometric measurement the  Beer' Law  must be taken into account.

Combining equation  (5)  and  Beer' Law

A  =  Absorbance,  e = Molar absorbtivity with units of  L · mol -1 · cm -1
c  =  Concentration of the absorbing species in solution, expressed in  mol · L -1,  d  =  Path length through the sample
Io =  Intensity of the initial light beam,  I  =  Intensity of the transmitted light

gives the relationship between  k'  and  lnA:



According to equation  (7),  a plot of lnA versus time should lead to a straight line whose slope is the pseudo-first order rate constant  k'.  The value of  k'  can then be divided by the known, constant concentration of the excess compound to obtain the true constant second order  k:


The  pseudo-first order rate constant k'  can be also determined from the  half-life t 1 / 2.



Measuring a second order reaction rate (see below) can be problematic: the concentrations of the two reactants must be followed simultaneously, which is more difficult; or measure one of them and calculate the other as a difference, which is less precise. A common solution for that problem is the pseudo first order approximation. As a general rule, a minimum of a 20-fold stoichiometric excess is necessary. A 50-fold or 100-fold stoichiometric excess is preferable.

3 years ago

Post Your Answer

More Questions On Physical Chemistry

Ask Experts

Have any Question? Ask Experts

Post Question

 
 
Answer ‘n’ Earn
Attractive Gift
Vouchers
To Win!!!
Click Here for details
Explain band spectrum?
 
 
you can assume it like fingerprints of any person. For every element you can have band spectrum. The transition spectrum patten is unique for every element. By transition i mean the...
  img
Suraj Prasad 6 months ago
 
Spectral bands are part of optical spectra of polyatomic systems, including condensed materials, large molecules, etc. Each line corresponds to one level in the atom splits in the molecules....
  img
Suraj Prasad 6 months ago
 
Wikipedia is good .Can you explain in your own words in short ?
 
Vineeth 6 months ago
how to decide boiling point
 
 
i tthink according to molecular weights
 
prasad one month ago
 
i think according to strength of bonding in molecule like hydrogen bonding,
 
ng29 one month ago
estimate the amount of magnesium that will be dissolved by a current of 01 ampere flowing for one hour
 
 
use the formula m=eit m=0.1x60x60e...............e=2/96500 m=7.46x10 -4
 
manyam 4 days ago
 
sorry 4 previous ans. i forgot to convert t in sec
 
manyam 4 days ago
 
1.24x10 -6
 
manyam 4 days ago
can sum1 explain me what why will be the structure of Cu(Cl)2- complex be ..with reasons.
 
 
Copper(II) chloride is the chemical compound with the chemical formula CuCl2. This is a light brown solid, which slowly absorbs moisture to form a blue-green dihydrate. The copper(II)...
  img
Saurabh Kumar 6 months ago
 
But in prabhat kumar it was given that since cl is a weak ligand it cannot pair up the electrons and the structure will be TETRAHEDRAL .can u please explain me in terms of VBT i.e....
 
sameer gupta 6 months ago
DPP C-26 Q.No.17 A mixture of camphor and benzoic acid can be separated by- the answer given is chemical method. But I think the correct answer is sublimation. Kindly advice.
 
 
By the process of sublimation, as camphor is...
  img
Harishwar 7 months ago
 
Thank you sir
 
Pranav Pramod Menon 4 months ago
Ph(CH2)(CH=CH2) + HBr = ?
 
 
First carbocation will e formed and then it will rearrange after rearrangement product Ph – CHBr – CH2 – CH3 will be formed. plz approve!
 
vikas yadav 4 months ago
 
(Ph)CH2-CHBrCH2-CH3
 
narenchemistry 4 months ago
View all Questions »