⏱️general chemistry ii review

key term - Catalysts

Definition

Catalysts are substances that increase the rate of a chemical reaction without being consumed in the process. They work by lowering the activation energy required for the reaction to occur, allowing more reactant molecules to collide with enough energy to react. This results in a faster reaction rate and can be crucial in various chemical processes, including industrial applications and biological systems.

5 Must Know Facts For Your Next Test

  1. Catalysts do not alter the overall energy change of a reaction; they simply speed up the rate at which equilibrium is reached.
  2. Catalysts can be classified as homogeneous (in the same phase as the reactants) or heterogeneous (in a different phase).
  3. Enzymes, a type of biological catalyst, are highly specific and can catalyze reactions with great efficiency under mild conditions.
  4. Catalysts can be poisoned or deactivated by impurities or changes in environmental conditions, which can significantly affect their performance.
  5. In some reactions, the presence of a catalyst may lead to the formation of different products by providing alternative reaction pathways.

Review Questions

  • How do catalysts affect the activation energy and the rate of a reaction?
    • Catalysts lower the activation energy required for a chemical reaction to occur. By providing an alternative pathway for the reaction, catalysts increase the number of reactant molecules that have sufficient energy to collide and react. This results in an increased reaction rate, allowing the system to reach equilibrium faster without altering the overall energy change of the reaction.
  • Compare and contrast homogeneous and heterogeneous catalysts and provide examples of each.
    • Homogeneous catalysts are in the same phase as the reactants, often found in liquid reactions where both catalyst and reactants are dissolved in solution. An example is sulfuric acid acting as a catalyst in esterification. Heterogeneous catalysts, on the other hand, exist in a different phase than the reactants, such as solid catalysts used in gas-phase reactions. An example would be solid platinum used to catalyze hydrogenation reactions in organic chemistry. Each type has its own advantages and challenges based on their physical states.
  • Evaluate how catalysts contribute to both industrial processes and biological systems, emphasizing their significance.
    • Catalysts are vital in industrial processes as they enhance reaction rates, making manufacturing more efficient and cost-effective. For instance, catalytic converters in automobiles reduce harmful emissions by facilitating chemical reactions at lower temperatures. In biological systems, enzymes act as catalysts that accelerate biochemical reactions necessary for life, such as digestion and metabolism. The significance lies in their ability to optimize reaction conditions and reduce energy requirements, ultimately making processes more sustainable and effective.