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The second order rate law
-dA/dt = k [A] [B]
for example if B is present in excess amount, the reaction rate reduces to pseudo first order,
A0=0.01 M
B0: 2 M
AT= 0.0 M
BT=1.99 M
so the reaction rate depends on the concentration of A and
the new reaction rate is pseudo first order;
-dA/dt = kı [A]
The third order rate law
-dA/dt = k [A2] [B]
If B is in excess amount, molarity of B0 is a very closer value to Bt ( for example ; B0= 2 M BT=1.99 M)
the reaction becomes to be pseudo second order.
-dA/dt = k [A2]
Behzat BALCI
enviromental enginneering of cukurova university
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∙ 12y ago
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How is the effect of concentration changes on the reaction rate seen in the rate?
That depends on the order of the reaction. If the reaction is zero order with respect to a reactant, then changing the concentration will have no effect on rate. If it is first order, then doubling the concentration will double the rate. If it is second order, then doubling the concentration will quadruple the rate.
What are pseudo-first order reactions and do they differ from first order reactions?
For the IUPAC definitions see the link below.
According to the rate law how do concentration affect rate?
The rate will be dictated by the rate law. The concentration may have NO effect on rate in a zero order reaction, or it may be directly proportional to the concentration in a first order reaction. Also, in second order reaction, doubling the concentration will increase the rate by FOUR times.
How many electrons does silver have to gave up in order to achieve a pseudo-noble-gas electron configuration?
Silver needs 7 more electrons to reach a "pseudo-noble gas" configuration.
How do you prove graphically that a reaction is first order?
If a reaction is first order, a graph of reaction rate against reagent concentration will be a straight line.
Why adsorption follows pseudo orders?
is because is not chemical reaction
Define Pseudo unimolecular reaction with example?
there is no meaning in pseudo unimolecular reaction. Explanation: molecularity of a reaction is "the no. of species(ions, molecules or atoms) which collide simultaneously to give rise a chemical change or chemical reaction. a reaction can be called unimolecular (decomposition of ammonium nitrite to nitrogen and water) as single molecule decomposes to give rise to products a reaction can be called bimolecular (HI decomposes to H2 and I2) as two HI molecules are colliding. that means molecularity says about "actually how many species collide and there is nothing ambiguity (pseudo) in it. but a reaction can be called pseudo first order reaction (hydrolysis of sucrose) as rate of reaction depends on only sucrose conc. and water solvent conc. as is in excess do not affect the rate. if any one is having doubts in chemistry u can mail me at chemistry_krish@yahoomail.com
What is the unit of first order reaction?
A zero-order reaction is a reaction that proceeds at a rate that is independent of reactant concentration. Typically with increasing or decreasing reactants
How is rate of a chemical reaction usually expressed?
Rates of reaction can be expressed depending upon their order.For example say you have a reaction between two chemicals and the initial rate for that reaction is known :-when:-The concentration of one of the reactants is doubled and the other reactants concentration remains the same and the overall rate of reaction does not change - reaction is zero orderwith respect to chemical which was doubled.The concentration of one of the reactants is doubled and other reactants concentration remains the same and the overall rate of reaction doubles - reaction is first order with respect to chemical which was doubled.The concentration of one of the reactants is doubled and other reactants concentration remains the same and the overall rate of reaction quadruples - reaction is second order with respect to chemical which was doubled.Zero Orderrate = kFirst Orderrate = k [A] (reaction is 1st order with respect to [A] and 1st order overall)Second Orderrate = k [A][B] (reaction is first order with respect to [A] and first order with respect to[B], reaction is second order overall)rate = k [A]2 (reaction is second order with respect to [A] and second order overall)Orders are simply added together in order to determine the overall order of reaction :-rate = k [A][B][C] would be third order overall and first order with respect to each of the reactantsThere are other orders of reaction, for example 2 and 3 quarter orders and third order reactions, but these are a little more complex.
How do you identify whether the order of the reaction is zero order first order or second order?
Linear system of arbitrary complexty can be viewed as being composed of first and second order
How is the effect of concentration changes on the reaction rate seen in the rate?
That depends on the order of the reaction. If the reaction is zero order with respect to a reactant, then changing the concentration will have no effect on rate. If it is first order, then doubling the concentration will double the rate. If it is second order, then doubling the concentration will quadruple the rate.
A reaction in which X and Y form products was found to be first order in X and second order in Y By what factor will the rate of the reaction change if X is doubled and Y is halved?
It will half.
What are the types of pseudo psychology?
Pseudo psychology is a type of psychology which deals with nontraditional sciences. Examples of pseudo psych are birth order relating to personalities, horoscopes, and psychic powers.
X is second order and Y is first order X plus Y-- XY Does the reaction occur in a single step in which X and Y collide?
Yes, the reaction occurs in the step where X and Y collide. The first step is part of an elementary reaction and in an elementary reaction, the order is nothing but the coefficient in front of the reactant.
What is the order of reaction if the half life of a reaction is halved as the initial concentration of the reactant is doubled.?
Second order. If the half life of a reaction is halved as the initial concentration of the reactant is doubled, it means that half life is inversely proportional to initial concentration for this reaction. The only half life equation that fits this is the one for a second-order reaction. t(1/2) = 1/[Ao]k As you can see since k remains constant, if you double [Ao], you will cause t(1/2) to be halved.
Why third order reaction usually not is not possible?
Third order reactions imply reaction between three molecules, which implies collision between three molecules. From a probability standpoint this is much less likely than, say, a second-order reaction, where only two molecules must come together.
What are pseudo-first order reactions and do they differ from first order reactions?
For the IUPAC definitions see the link below.
