CHEM 100 Chapter Notes - Chapter 4: Molecular Mass, Chemical Formula, Formula Unit
Document Summary
4. 1 chemical formulas and formula masses. Formula states how many atoms of each element are in a fundamental unit of the compound. Formula mass the sum of the relative masses of all the atoms in the formula unit. The formula unit represents only the compound"s compositions. The mass units cannot be in grams but must be in atomic mass units (amu) Formula mass identical to the molecular mass. Molecular mass the mass in amu of a molecule of a molecular substance. A compound"s formula mass can only be calculated only if its formula is known. Different elements must contain equal numbers of atoms when the mass of each sample (in grams) is identical with each element"s relative mass in atomic mass units. Mole (mol) the number of atoms contained in the atomic mass (in grams) of an element and the number of formula units contained in the formula mass (in grams) of a compound are the fundamental chemical quantities.
