Understanding Solids (The Science of Materials) || Supplementary Material to Part 1: Structures and Microstructures

✍ Scribed by Tilley, Richard J. D.

• Publisher: John Wiley & Sons, Ltd
• Year: 2005
• Tongue: English
• Weight: 145 KB
• Category: Article
• ISBN: 0470852755
• DOI: 10.1002/0470020849.app1

✦ Synopsis

S1.1 Chemical equations and units

Chemical reactions are summarised by writing a chemical equation. By convention the reactants are on the left-hand side and the products are written on the right-hand side in the following format:

Reactants ! Products Some reactions can proceed in either direction and it is not then possible to specify the products or the reactants uniquely. These are written:

Reactants Ð Products Chemical equations are devices for 'accounting'. In the course of chemical reactions, no atoms must be lost or gained. Chemical equations should therefore be 'balanced' to ensure that this rule holds. Typical balanced equations are:

Sometimes it is desirable to specify the state of the reactants, whether solid, liquid or gas, or in solution. In such cases a symbol enclosed in brackets after the species gives this data; s ¼ solid; l ¼ liquid; g ¼ gas; aq ¼ water (aqueous) solution. These are only labels and are not a part of the reaction. For example: CaCO 3 ðsÞ ! CaO ðsÞ þ CO 2 ðgÞ