Chemistry · Ch 7 — Chemical Kinetics
Introduction
Introduction
You already know, from Class XI thermodynamics, how to predict whether a reaction CAN happen under a given set of conditions -- but thermodynamics is completely silent on how FAST it happens. Some reactions are essentially instantaneous: mix BaCl2 solution with dilute H2SO4 and a white precipitate of BaSO4 forms immediately. Others, like the rusting of iron, take years. This unit is about that missing piece: how fast a chemical change occurs, and what happens, step by step, between the starting materials and the final product.
What this unit sets out to do. By the end of it you should be able to:
- define the rate and order of a reaction;
- derive the integrated rate equations for zero- and first-order reactions;
- describe the half-life period of a reaction;
- describe collision theory;
- discuss how the rate of a reaction depends on temperature;
- explain the various factors that affect a reaction's rate.
Svante Arrhenius, one of the founders of physical chemistry, won the 1903 Nobel Prize in Chemistry for proposing that crystalline salts dissociate into charged ions when dissolved in water. He also formulated the concept of activation energy -- central to this unit's account of why temperature so strongly affects reaction rate.