CHM 111 Lecture Notes - Lecture 8: Mass Number, Atomic Number, Chemical Element

• School: University of Miami
• Department: Chemistry
• Course: CHM 111
• Professor: Lewis Nita

Document Summary

Law of conservation of mass: this law states that matter can neither be created nor destroyed, in other words, in any given chemical operation, an equal quantity of matter exists before and after the operation. Law of combining volumes: this law states that two gases, at the same temperature and pressure, combine in simple integers. Joseph louis gay-lussac also stated in studying gaseous reactions that volumes are not conserved. Dalton, however, disagreed and explained that all elements combined to form simple diatomic molecules and were therefore, conserved. Matter consists of indivisible atoms. (incorrect and obsolete because of the discovery of sub-atomic particles) All of the atoms of a given chemical element are identical in mass and all other properties. (incorrect and obsolete because of the discovery of isotopes) Different chemical elements have different kinds of atoms, and, in particular, such atoms have different masses. Atoms are indestructible and retain their identity in chemical reactions.