The main difference between chemical and physical reactions lies in the changes occurring at the molecular level. Here are the key distinctions between the two types of reactions: Chemical Reactions: These involve changes in the composition of the substances in question, resulting in the formation of one or more new substances with new properties. Chemical reactions typically involve changes in chemical bonds, and they are often accompanied by the production of energy in the form of heat, light, or sound. Examples of chemical reactions include burning leaves, digesting carrots, and the rusting of metals.
Physical Reactions: These involve changes in the appearance, smell, or display of a sample of matter without a change in composition. Physical reactions are temporary and can be easily reversed, meaning the original substance can be recovered. They primarily involve changes in intermolecular forces, such as texture, color, temperature, shape, and state (boiling and melting points). Examples of physical reactions include cutting a diamond, crushing a pencil, and salt mixing in water. It is important to note that some processes do not fit neatly into one category, as they may involve both physical and chemical changes, such as the dissolving of salt in water. In these cases, ionic bonds are broken (suggesting a chemical process), but no new substances are formed (suggesting a physical process).