Summary of "Lec 6.1 - Catalysis"

Summary of Scientific Concepts and Discoveries

Catalysts:
- Definition: A catalyst is a substance that increases the rate of a chemical reaction without undergoing any permanent change itself.
- Types of Catalysts:
  - Homogeneous Catalysis: Catalyst and reactants are in the same phase (e.g., all in a liquid solution).
  - Heterogeneous Catalysis: Catalyst and reactants are in different phases (e.g., solid catalyst with liquid or gas reactants).
  - Homogeneous Biological Catalysts: Biological molecules (e.g., enzymes, RNA) acting as Catalysts within a medium (often aqueous).
Activation Energy:
Catalysts provide an alternative reaction pathway with lower Activation Energy, allowing more molecules to reach the necessary energy for the reaction to occur.
Applications of Catalysis:
- Catalysts are extensively used in the chemical industry, including the production of fertilizers and various products.
- Examples include the catalytic converters in vehicles that reduce harmful emissions and the use of platinum as a catalyst in reactions involving hydrogen and oxygen.
Kinetics and Rate Constants:
The presence of a catalyst significantly increases the rate constant of a reaction, exemplified by a problem involving the decomposition of hydrogen peroxide where the rate constant increased by a factor of 2,100 with the addition of iodide ion.
Catalyst Activity and Selectivity:
- Activity: Refers to how effectively a catalyst speeds up a reaction.
- Selectivity: Indicates the preference of a catalyst for a particular reaction over others, minimizing side reactions.
Thermodynamics of Catalysis:
Catalysts do not affect the extent of the reaction (how far it goes) but speed up both the forward and reverse reactions equally.
Challenges and Research:
Research is ongoing to find cheaper and more effective Catalysts, particularly in processes like oil refining and fuel cells.

Methodology and Problems Presented

Example Problem:
Calculate the increase in the rate constant when a catalyst is added, using the activation energies provided.
Factors Affecting Reaction Rates:
- Temperature
- pH (concentration of hydronium ions)
- Concentration of reactants and Catalysts