ations and Chemical EquationsAtomic mass: Mass of an ATOM of an element, expressed in atomic mass units Atomic mass unit (amu): 1.661 x 10-24gAtomic weight: Average mass of all isotopes of a given element; listed on the periodic tableExample: Hydrogen atomic weight = 1.008 amuCarbon atomic weight = 12.001 amuCarbon atoms are 12 times as massive as hydrogen atomsPractice: Ca atomic mass = 40.08 amuNe atomic mass = 20.18 amuHow MANY Neon atoms are required to give the same mass as one calcium atom?Avogadro’s Number: The Mole1 Dozen = 121 Gross = 1441 Mole = 6.02 x 10231 mole of atoms = 6.022 x 1023 atoms1 mole of molecules = 6.022 x 1023 moleculesMolar Mass: the mass (in grams) of one mole a particular substanceThere is a UNIQUE relationship between molar mass and atomic weight:Oxygen’s atomic weight is 16.00 amu. 1 mole of oxygen is 6.02 x 1023 atoms of oxygen1 amu = 1.661 x 10-24gWhat is the molar mass (g/mole) of oxygen?16.00 amu/oxygen atom x 1.661 x 10-24g/amu= 2.657 x 10-24 g/atom x 6.02 x 1023 atoms/mole=16.00 g/moleMolar mass (in grams) is always equal to the atomic weight of the atom!Molar mass (in grams) is always equal to the atomic weight of the atom!Examples: Atomic weight of carbon is 12.01amuMolar mass of carbon is 12.01 g/molAtomic weight of helium is 4.00 amuMolar mass of helium is 4.00 g/molMole (mol): The number of particles (atoms or molecules) in a sample of element or compound with a mass in grams equal to the atomic (or MOLECULAR) weightExample: Atomic weight of sodium = 22.9922.99 g of sodium contains 1 mole (6.02 x 1023) of atoms I think it's helpful for you ☺