38 Questions
Which type of catalysis involves a catalyst and reactants in the same phase?
Homogeneous catalysis
What is a characteristic of heterogeneous catalysis?
Difficult separation from the reaction mixture
Which biochemical compound is primarily involved in enzyme catalysis?
Proteins
Which type of catalysis is known for its high activity and selectivity?
Enzyme catalysis
What is a characteristic of homogeneous catalysis?
Same phase between catalyst and reactants
Which type of catalysis is characterized by low environmental friendliness?
Homogeneous catalysis
What is a characteristic of enzyme catalysis?
Low environmental impact
Which type of catalysis is more eco-friendly and easy to handle?
Heterogeneous catalysis
What is the primary characteristic of homogeneous catalysis?
High selectivity
Which type of catalysis is characterized by the catalyst existing in a different phase than the reaction mixture?
Heterogeneous catalysis
What is the advantage of heterogeneous catalysis in terms of separation from the reaction mixture?
Easy separation and reutilization
Which type of catalysis is known for its high activity and selectivity?
Enzyme catalysis
What is the difference between reactants and catalyst in homogeneous catalysis?
They are in the same phase
What is the environmental impact of homogeneous catalysis?
Less environmental friendly due to the formation of toxic products
What is the characteristic of the catalyst in heterogeneous catalysis?
It is a solid
What is the purpose of biochemical catalysts in the body?
To speed up biochemical reactions
What is the major reason for the slow reaction between S2O82- and 2Fe2+ in water?
Repulsion between the negative ions
What is the role of Co2(CO)8 in the carbonylation of methanol?
Catalyst
What is the product of the hydrolysis of nitramide in the presence of OH- ions?
N2O
What is the role of NO in the oxidation of SO2?
Intermediate
What is the catalyst used in the Freidel-Craft's reaction?
Anhydrous AlCl3
What is the purpose of using iron(II) as a catalyst in the reaction between S2O82- and 2Fe2+?
To avoid the problem of repulsion between negative ions
What is the role of chlorine in the decomposition of ozone?
Catalyst
What is a characteristic of homogeneous catalysis?
High selectivity and high reactivity
What is the common feature of the mechanisms of the catalyzed reactions mentioned in the text?
They all involve a catalyst
What phase do the reactants and catalyst exist in for heterogeneous catalysis?
Different phases
Which type of catalysis is known for its high activity and high selectivity?
Enzyme catalysis
What is the phase of the catalyst in most heterogeneous catalysis?
Solid
Which of the following catalysis types involves reactants and the catalyst in the same phase?
Homogeneous catalysis
What is the characteristic of enzyme catalysis in terms of selectivity and activity?
High activity and high selectivity
What is the result of the breakdown of ozone molecules?
We experience more intense UV radiation at the earth's surface.
What is the role of the catalyst in homogeneous catalytic processes?
To reduce the activation energy involved in the formation of intermediates.
What is the theory that explains the mechanism of catalytic reaction?
The theory of activated complex
What is the equation that represents the acceleration of the catalytic reaction?
e-Ecat/RT / e-Enon-cat/RT = e ΔE/RT
What is the effect of a reduction in activation energy of 10 Kcal/mol in a catalytic reaction at 300K?
The rate will be accelerated by 2.05 x 10^7 times.
What is the intermediate compound formed in the catalytic reaction?
AC and ABC
What is the final product formed in the catalytic reaction?
P
What is the characteristic of the activated complex formed in the catalytic reaction?
It is highly reactive.
Study Notes
Types of Catalysis
- There are three classes of catalytic reactions: homogeneous catalysis, heterogeneous catalysis, and enzyme catalysis (biocatalysis).
Homogeneous Catalysis
- The catalyst is in the same phase as the reaction mixture.
- Characterized by high selectivity and high activity with maximum selectivity.
- Operates under mild conditions, i.e., thermal unstable.
- Difficult separation from the reaction mixture and reutilization of the catalyst is less possible.
- Less environmental friendly due to the formation of toxic products.
- Examples include:
- Reaction between persulphate and iodide ions
- Carbonylation of methanol
- Hydrolysis of nitramide in presence of OH- ions
- Oxidation of SO2 in presence of NO
- Decomposition of H2O2 in presence of dichromate
- Freidel-Craft's reaction
- Decomposition of ozone (hole of ozone)
Heterogeneous Catalysis
- The catalyst acts in a different phase than the reaction mixture.
- Characterized by relatively high activity with perhaps low selectivity.
- Most heterogeneous catalysts are solids that act on reactants in a liquid or gaseous reaction mixture.
- Easy separation from the reaction mixture and reutilization of the catalyst is possible.
- Eco-friendly, easy to handle, and can be operated at strong reaction conditions.
- Most heterogeneous catalysts are solids acting on reactants in a liquid or gaseous phase.
Enzyme Catalysis (Biocatalysis)
- Biochemical catalysts are helpful to speed up biochemical reactions in the body.
- Made up of proteins.
- Characterized by high activity and selectivity.
- Low environmental impact.
- Primarily consists of proteins.
Key Concepts
- The theory of activated complex (intermediate compound theory) can be used to explain the mechanism of the catalytic reaction.
- The catalyst converts the reactant into an unstable intermediate (a high reactive state).
- An activated complex is formed due to the interaction between the intermediate compound and the second reactant.
- The unstable activated complex is relatively slowly dissociated to the final reaction product.
- The catalytic reaction will be accelerated by a reduction in activation energy.
- The rate of reaction can be accelerated by a factor of 2.05 x 10^7 times for a reduction in activation energy of 10 Kcal/mol in a catalytic reaction at 300K.
Learn about the different types of catalysis, including homogeneous, heterogeneous, and biocatalysis, and their characteristics.
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