CHEM 1A Chapter 2-3: Chapter 2 Atoms and Chapter 3 Stoichiometry

• School: UCSB
• Department: Chemistry and Biochemistry
• Course: CHEM 1A
• Professor: T B A

Document Summary

Law of conservation of mass: mass is neither created nor destroyed. The total mass before a chemical reaction always equals the total mass after a chemical reaction. Law of definite proportion: a given compound always contains exactly the same proportion of elements by mass. For example, water is always 1 g hydrogen for every 8 g oxygen. Law of multiple proportions: when two elements form a series of compounds, the ratios of the mass of the second element that combine with 1 g of the first element always can be reduced to small whole numbers. Element: substance consisting of one type of atom. Examples of elements- h2, o2 (hydrogen and oxygen are diatomic), c. Compound: substance consisting of two or more types of atoms. Elements: most elements are monatomic, i. e. na (s), ar (g), he (g), hg (l, some elements are diatomic: