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🔬 Chapter 9: Rates of Reaction 🔬
Learning Outcomes 🎯:
Understand reaction kinetics and the factors affecting the rates of chemical reactions.
Recognize the role of surface area, concentration, temperature, and catalysts in reaction rates.
Understand the concept of activation energy and its role in determining the rate of reaction.
Differentiate between homogeneous and heterogeneous catalysts.
Understand the Boltzmann distribution of molecular energies and how it changes with temperature.
Factors Affecting Rate of Reaction 📈:
Surface Area: Finely divided solids have a larger surface area, leading to more frequent collisions and a faster reaction rate.
Concentration and Pressure: Higher concentration or pressure leads to more frequent collisions between reactant molecules, increasing the reaction rate.
Temperature: At higher temperatures, molecules have more kinetic energy, leading to more frequent and successful collisions.
Catalysts: Catalysts increase the rate of reaction by providing an alternative reaction pathway with a lower activation energy.
Activation Energy ⚡:
Activation energy is the minimum energy required by colliding particles for a reaction to occur.
It acts as a barrier to reaction, and only particles with energy greater than the activation energy can react.
Boltzmann Distribution 📊:
The Boltzmann distribution represents the number of molecules in a sample with particular energies.
At higher temperatures, the distribution changes, showing that more molecules have energy greater than the activation energy, leading to an increase in reaction rate.
Catalysis 🧪:
Catalysts lower the activation energy, allowing a greater proportion of molecules to have sufficient energy to react.
Homogeneous catalysts are in the same phase as the reactants, while heterogeneous catalysts are in a different phase.
Enzymes are biological catalysts that provide an alternative reaction pathway of lower activation energy.