UNIT CH1 - Controlling and Using Chemical Changes

Controlling and Using Chemical Changes (in order to make things, produce energy and solve environmental problems)

This unit begins with some important fundamental ideas about atoms and the use of the mole concept in calculations. Three key principles governing chemical change are then studied, viz., the position of equilibrium between reactants and products, the energy changes associated with a chemical reaction and the rate at which reactions take place. These principles are then applied to some important problems in the fields of chemical synthesis, obtaining energy and the maintenance of the environment.

2.3 - Kinetics

Learning outcomes

Candidates should be able to:

(a) name the factors affecting reaction rates, including light in some cases;

(b) outline a method of measuring the rate of a given reaction, explaining the principles involved;

(c) calculate initial rates from graphs of concentration against time and understand how the results can give the relationship between rate and reactant concentrations;

(d) describe simple collision theory and qualitatively explain the effects of changes in concentration (or pressure) and temperature on rate by means of this theory;

(e) define activation energy, describe the concept of energy profiles and recall that .H = Ef - Eb;

(f) explain the rapid increase in rate with temperature in terms of changes in the energy distribution curve;

(g) recall the function of a catalyst and understand that at any temperature the presence of a catalyst:

(h) recall that catalysts may be homogeneous or heterogeneous and be able to give one example of each type;

(i) appreciate the importance of finding new and better catalysts, including the use of enzymes, in achieving some of the goals of green chemistry, e.g., allowing the possibility of lower temperatures (less energy consumption), lower pressures, etc.;

(j) appreciate the distinction between what may be deduced from equilibrium data and what may be deduced from kinetic data.