Unit 6: Chemical Quantities Chapter 10: The Mole and Molar Mass

The Mole and Molar Mass Atomic Mass is expressed in amu (atomic mass units) Where can you find the amu of an element? Periodic Table Molar Mass One mole of any substance is equal to the atomic mass expressed in grams 1 mol = molar mass (g/mol) = atomic mass (g) Gram Atomic Mass (GAM) = Elements Gram Formula Mass (GFM) = Ionic Compounds Gram Molecular Mass (GMM) = Molecular Compounds

The Mole and Molar Mass Calculating Molar Mass Count the number of atoms in the substance. Find the atomic mass of each element from the Periodic Table. Round each one to one decimal place. Multiply the number of atoms of each element by the atomic mass of that element. Add the values together to get the total molar mass for that substance.

The Mole and Molar Mass Calculating Molar Mass Example 1: What is the molar mass of iron (III) oxide, Fe2O3? 1) # of Atoms 2) Atomic Mass 3) Multiply 2 Fe 55.8 x 2 = 111.6 3 O 16.0 x 3 = 48.0 Fe2O3 159.6 g/mol

The Mole and Molar Mass Calculating Molar Mass Determine the mass in grams of the following substances: O2 = NaCl = C3H8 =

The Mole and Molar Mass Conversions You can use the molar mass to convert from moles to grams and vice versa 1 mol = molar mass (g/mol) Conversion factors are… or Mass (grams) 1 mole 1 mol Mass (grams)

The Mole and Molar Mass Practice: What is the mass of 9.45 mol of Aluminum Oxide? Find the formula for Aluminum Oxide Find the molar mass of the compound Then use the conversion 1 mole = mass of the compound 9.45 mol Al2O3 102.0 g Al2O3 = 964 g Al2O3 1 mol Al2O3

The Mole and Molar Mass Practice : How many moles are of iron (III) oxide are contained in 92.2 g? 92.2 g Fe2O3 1 mol Fe2O3 = 0.578 mol Fe2O3 159.6 g Fe2O3