12 Questions
What is the primary reason why increasing the concentration of reactants in a solution increases the rate of reaction?
It increases the number of collisions between reactants
How do enzymes increase the rate of reaction?
By taking reactants out of dilute solution and holding them close to each other
What is the role of the catalyst in the intermediate formation theory of catalysis?
It forms intermediate compounds with reactants
Why are intermediate compounds formed in the intermediate formation theory of catalysis?
To allow the catalyst to form bonds with reactants
What is a characteristic of the intermediate compound formed in the intermediate formation theory of catalysis?
It is very unstable
Why are reactions involving catalysts faster than uncatalyzed reactions?
Because they have lower activation energy
What is the typical reaction scheme represented in the given equation?
Reaction of reactants X and Y
What is the characteristic of heterogeneous catalysts?
The reactants and catalyst are in different phases
What is the role of the substrate in industrial applications of heterogeneous catalysts?
To increase the effective surface area of the catalyst
What is the process by which the reactants are adsorbed onto the surface of the catalyst?
Chemical reaction
What is the characteristic of a good catalyst?
It binds moderately well to the reactants and products
What is the term for the phenomenon where one of the products acts as a catalyst?
Autocatalysis
Study Notes
Factors Affecting Reaction Rates
- Proximity of reactants increases reaction rates, as it increases the number of collisions between reactants
- Enzymes work by binding reactants, increasing their effective concentration and leading to increased reaction rates
The Intermediate Formation Theory of Catalysis
- Catalysts form intermediate compounds with reactants, which then react to form products
- Intermediate compounds are unstable and break down to release products and the original catalyst
- This process is faster than the uncatalyzed reaction
Reaction Scheme
- X + C → XC (1)
- XC + Y → XYC (2)
- XYC → CZ (3)
- CZ → C + Z (4)
Heterogeneous Catalysis
- Catalyst and reactants are in different phases (e.g., solid catalyst, liquid or gas reactants)
- Catalyst is often supported on a substrate to increase surface area and stability
- Reactants adsorb onto the catalyst surface, migrate, react, and then desorb as products
Autocatalysis
- One of the products acts as a catalyst, increasing the reaction rate over time
- Examples include the oxidation of oxalic acid by acidified potassium permanganate and the reaction between nitric acid and copper
This quiz explores how proximity affects chemical reaction rates, including the role of enzymes and concentrations of reacting molecules.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
