AS and A2 Chemistry notes and resources (WJEC specification) - UNIT CH2. Properties, Structure and Bonding

The uses to which materials can be put depend on their properties, which in turn depend on the bonding and structure within the material. By understanding the relationship between these factors, chemists are able to design new materials. The types of forces that can exist between particles are studied, along with several types of solid structures, in order to illustrate how these factors influence properties. The building blocks of materials are the elements and the relationship of their properties to their position in the Periodic Table is illustrated by a study of the elements of the s-block and Group 7. An introduction to organic chemistry provides the basis for an understanding of how the properties of carbon compounds can be modified by the introduction of functional groups.

7.3 - Halogenoalkanes

Candidates should be able to:

(a) describe the formation of a chloroalkane by direct chlorination of alkanes ¢Ó*;

(b) describe the substitution reaction between . OH and 1-chlorobutane and explain this on the basis of the recalled mechanism. ¢Ó*;

(c) show an awareness of the wide use of halogenoalkanes as solvents, the toxicity of some of them, the use of CFCs as refrigerants and in aerosols, and their use in anaesthetics as well as the adverse environmental effects of CFCs;

(d) understand the adverse environmental effects of CFCs and explain these in terms of the relative bond strengths of the C . H, C . F, and C . Cl bonds involved;

(e) show an awareness of the use of organohalogen compounds as pesticides and polymers and assess their environmental impact.