Chemical Reactions Overview

There are several main categories of chemical reactions, including:

1. Synthetic reactions: These create new substances from existing elements by joining or separating atoms. Common examples include combustion, halogenation, oxidation, and hydrolysis.

2. Organic reactions: These involve organic compounds, typically found in living things. Examples of organic reactions include esterification, dehydration, and open chain polycondensation.

3. Metallurgical reactions: These involve metals, particularly their melting and casting. Examples include smelting and refining ore to produce metal ingots.

4. Decomposition reactions: These split a substance into simpler parts. Examples include rusting iron, burning wood, and dissolving salt in a liquid.

In these reactions, the components, often referred to as reactants, are transformed into something else, known as the products. The change occurs because the energy levels of electrons change, causing them to move more rapidly around the nuclei or to interact differently with the nuclei themselves. Reactions can proceed in either the forward or reverse directions, depending on circumstances such as differences in energy levels.

Some reactions result in changes of state, such as liquids evaporating into gases or solids dissolving in liquids. Others cause reactions to start spontaneously, creating chemical conditions that no longer exist once the reaction starts. Still others combine substances to form complex mixtures, producing new materials with unique structural arrangements.