CHEM 1040 Final: Final Exam Notes
Document Summary
Chapter 3: calculations with chemical formulas and equations. The molecular mass of a substance is the sum of the atomic masses of all the atoms in a molecule of the substance. The formula mass of a substance is the sum of the atomic masses of all atoms in a formula unit of the compound, whether molecular or not. A mole (mol) is defined as the quantity of a given substance that contains as many molecules or formula units as the number of atoms in exactly 12g of carbon-12. The number of atoms in a 12-g sample of carbon-12 is called avogadro"s number (na). Avogadro"s number is given the value 6. 02 x 10-23. A mole of a substance contains avogadro"s number of molecules (or formula units) The term mole refers to a particular number of things. In using the term mole for ionic substances, we mean the number of formula units of the substance.
