CHY 103 Lecture 2: CH3-1.pdf
Document Summary
Atomic mass unit (amu): a mass unit equal to exactly one-twelfth (1/12) the mass of a carbon atom (1. 6605402x10-27 kg). Molecular mass: the sum of the atomic masses of all atoms in a molecule of substance. Formula mass: the sum of the atomic masses of all atoms in a formula unit of the compound. Example: calculate the formula weight of calcium hydroxide. Mole: the quantity of the substance having the same number of elementary entities as there are in. 12 g (exactly) of carbon-12, namely 6. 022 x 1023 (avogadro"s number, na). Elementary entities may be atoms, molecules, ions, or specified groups. Molar mass: (m, units g mol-1) the mass of avogadro"s number, na, of elementary entities x, symbol mx, e. g. mo = 15. 999 g mol-1, For all substances, the molar mass in grams per mole is numerically equal to the formula weight in atomic mass units.
