Rates of Reaction and Catalysis

Rate of Reaction

• Defined as the change in concentration of reactants or products per unit time
• Typically measured in units of mol/L·s
• Can be expressed as an average rate or an instantaneous rate
• Factors affecting rate of reaction:
  • Concentration of reactants
  • Temperature
  • Surface area of reactants
  • Presence of catalysts

Catalysis

• A catalyst is a substance that speeds up a chemical reaction without being consumed or altered
• Catalysts work by lowering the activation energy required for the reaction
• Types of catalysis:
  • Homogeneous catalysis: catalyst is in the same phase as the reactants
  • Heterogeneous catalysis: catalyst is in a different phase from the reactants
• Examples of catalysts:
  • Enzymes in biological systems
  • Metals in industrial processes

Activation Energy

• The minimum energy required for a chemical reaction to occur
• Represented by the symbol Ea
• Can be thought of as the "energy barrier" that must be overcome for a reaction to proceed
• Factors affecting activation energy:
  • Temperature
  • Presence of catalysts
  • Surface area of reactants

Collision Theory

• A model that explains how chemical reactions occur
• Postulates that reactant molecules must collide with sufficient energy and proper orientation to react
• Factors affecting collision frequency:
  • Concentration of reactants
  • Temperature
  • Surface area of reactants
• The collision theory explains the effects of temperature, concentration, and catalysts on reaction rates

Rate-determining Step

• The slowest step in a reaction mechanism that determines the overall rate of the reaction
• Identifying the rate-determining step is crucial in understanding the kinetics of a reaction
• The rate-determining step can be affected by:
  • Concentration of reactants
  • Temperature
  • Presence of catalysts
• Understanding the rate-determining step can help optimize reaction conditions to increase reaction rates.

Rate of Reaction

• Defined as the change in concentration of reactants or products per unit time
• Measured in units of mol/L·s
• Can be expressed as an average rate or an instantaneous rate
• Factors affecting rate of reaction include concentration of reactants, temperature, surface area of reactants, and presence of catalysts

Catalysis

• A catalyst is a substance that speeds up a chemical reaction without being consumed or altered
• Catalysts lower the activation energy required for the reaction
• Types of catalysis include homogeneous catalysis and heterogeneous catalysis
• Examples of catalysts include enzymes in biological systems and metals in industrial processes

Activation Energy

• The minimum energy required for a chemical reaction to occur
• Represented by the symbol Ea
• Can be thought of as the energy barrier that must be overcome for a reaction to proceed
• Factors affecting activation energy include temperature, presence of catalysts, and surface area of reactants

Collision Theory

• A model that explains how chemical reactions occur
• Reactant molecules must collide with sufficient energy and proper orientation to react
• Factors affecting collision frequency include concentration of reactants, temperature, and surface area of reactants
• The collision theory explains the effects of temperature, concentration, and catalysts on reaction rates

Rate-determining Step

• The slowest step in a reaction mechanism that determines the overall rate of the reaction
• Identifying the rate-determining step is crucial in understanding the kinetics of a reaction
• Factors affecting the rate-determining step include concentration of reactants, temperature, and presence of catalysts
• Understanding the rate-determining step can help optimize reaction conditions to increase reaction rates

Learn about the rate of reaction, its measurement, and factors that affect it, as well as the concept of catalysis and how catalysts work.