CHEM 1122 Lecture Notes - Lecture 5: Ion, Spectator Ion, Nonmetal
Document Summary
Chemical reaction - the transformation of one or more substances into different substances. Gas evolution reactions - reactions that occur in liquids and form a gas (ex: fizzing of antacids) Subcategory of oxidation - reduction reactions - electrons are transferred from one substance to another (ex: formation of dust and automobile paint) When sodium carbonate dissolves in water, it dissociates , or separates into sodium ions and carbonate ions. Precipitation reactions - reactions that form solid substances in water (used to remove dissolved toxic metals in industrial wastes) Evidence that a chemical reaction has occurred: While these changes provide evidence of a chemical reaction, they are not definitive evidence. Only chemical analysis showing that the initial substances have changed into other substances conclusively proves that a chemical reaction has occurred. The changes occurring at the atomic and molecular level determine whether a chemical reaction has taken place.
