Presentation on theme: "Molar Mass. The Mass of 1 mole (in grams) Equal to the numerical value of the average atomic mass (get from periodic table) 1 mole of C atoms= 12.0."— Presentation transcript:
The Mass of 1 mole (in grams) Equal to the numerical value of the average atomic mass (get from periodic table) 1 mole of C atoms= 12.0 g 1 mole of C atoms= 12.0 g 1 mole of Mg atoms =24.3 g 1 mole of Cu atoms =63.5 g Molar Mass
Other Names Related to Molar Mass Molecular Mass/Molecular Weight: If you have a single molecule, mass is measured in amu’s instead of grams. But, the molecular mass/weight is the same numerical value as 1 mole of molecules. Only the units are different. (This is the beauty of Avogadro’s Number!) Formula Mass/Formula Weight: Same goes for compounds. But again, the numerical value is the same. Only the units are different. THE POINT: You may hear all of these terms which mean the SAME NUMBER… just different units
Find the molar mass (usually we round to the hundredths place) Learning Check! A.1 mole of Br atoms B.1 mole of Sn atoms =79.90 g/mole = 118.69 g/mole
What if we have a compound? Mixed beans 1 Red is 12 amu, 1 Maroon is 14 amu, 1 Black is 32 amu (from P.Table) or 12g per mole, 14g per mole, 32g per mole The ratio of beans in the container is 2 red : 1 maroon : 3 black What is the mass of one set? 12 x 2 + 14 x 1 + 32 x 3 = 134amu or 134g R 2 MB 3 /1 mole R 2 MB 3
Mass in grams of 1 mole equal numerically to the sum of the atomic masses 1 mole of CaCl 2 = 111.1 g CaCl 2 /mol CaCl 2 1 mole Ca x 40.1 g Ca/mol Ca + 2 moles Cl x 35.5 g Cl/mol Cl = 111.1 g/mol CaCl 2 1 mole of N 2 O 4 = ? = 92.0 g/mol Molar Mass of Molecules and Compounds
A. Molar Mass of K 2 O = ? Grams/mole B. Molar Mass of antacid Al(OH) 3 = ? Grams/mole Learning Check!