Important Talent Search Exams
|Allen TALLENTEX 2018 (Class 5 to 11)|
|Aakash ANTHE 2017 : 100% Scholarship (Class 8, 9, 10)|
Catalyst: A substance that can influence the rate of a chemical reaction but itself does not undergo the permanent chemical change.
Catalyst increases the reaction rate by lowering the activation energy of the reactant.
Eq → Activation energy without catalyst
Eq → Activation energy with catalyst
ER → Energy of reaction
A → Path of reaction without catalyst
B → Path of reaction with catalyst.
Catalysis: The process in which rate of reaction is influenced by catalyst is called catalysis.
Substrate: The reactant on which catalyst acts is called substrate.
Catalyst does not change the heat of reaction it only makes a process faster.
Catalyst does not change the yield of the product
Type of Catalyst:
Positive Catalyst: A catalyst which increase the rate of reaction by lowering the activation energy of reaction.
Negative Catalyst: A catalyst that retards the chemical reaction by raising the energy barrier or activation energy.
Types of catalysis
Homogeneous Catalysis: Catalysis in which catalyst and reactants are present in same phase.
Heterogeneous Catalysis: Catalysis in which Catalyst and reactants are in different phase.
Effect of catalyst on the Rate of Reaction:
According to the Arrhenius theory
Thus specific rate of reaction (rate constant k) depends upon two factors
when we employ catalyst Ea of reaction is lowered and more no. of molecules possesses energy above the threshold temperature rate of reaction increases.
If at temperature T rate constant is K1 for uncatalyzed reaction and rate case is K2 for catalyzed reaction
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