Catalysts
Specification Reference Physical Chemistry, Kinetics 3.1.5.5
Quick Notes
- A catalyst increases the rate of a reaction without being used up.
- Catalysts work by providing an alternative reaction pathway with a lower activation energy (Ea).
- Effect on Maxwell-Boltzmann distribution:
- Lowers activation energy (Ea), increasing the number of particles with energy ≥ Ea.
- No shift in distribution curve, but the activation energy threshold moves left.
Full Notes
What is a Catalyst?
A catalyst is a substance that speeds up a reaction without being used up.
It works by providing an alternative reaction pathway with a lower activation energy (Ea).
This increases the frequency of successful collisions, meaning an increased rate of reaction.
Catalysts and the Maxwell-Boltzmann Distribution
Catalysts cause no change to the curve shape of a Maxwell-Boltzmann distribution, but the activation energy threshold shifts left, meaning a greater proportion of gas reactant particles can now react.
Benefits of Catalysts in Industry
- Reduce energy costs by lowering required temperatures.
- Increase reaction rates, improving efficiency.
- Allow alternative reactions with higher atom economy, reducing waste.
- Reduce environmental impact, such as cutting CO2 emissions.
Summary
- Catalysts increase reaction rate without being used up.
- They provide an alternative pathway with lower activation energy (Ea).
- On a Maxwell-Boltzmann curve, the distribution shape does not change but the activation energy shifts left.
- Industrial benefits include cost reduction, higher efficiency, and environmental improvements.