CHEM 20A Lecture Notes - Lecture 2: Atomic Number, Chemical Equation, Phlogiston Theory
Document Summary
A substance that was believed to be given off during combustion. It was thought to be a universal component of fire. A substance was believed to have lost weight and mass during combustion due to loss of its phlogiston. This idea was later proved to be wrong because oxidation adds to the mass of the substance. Elements combine in the same proportion by mass. When two elements of the same amount combine to form compounds, the ratio of the masses is a simple one i. e. c & o combine to form co and co2. The proportion by mass of elements in a compound remains, regardless of where the substance was obtained. Made way for the periodic table by publishing a set of consistent atomic weights. Gasses combine as a ratio of simple volumes. The volume of each gas involved in a reaction is proportional to the number of molecules of that gas in the balanced chemical equation for that reaction.