Molar mass is the mass in grams of one mole of particles (atoms, ions, molecules, formula units). 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 Mg atoms = 24.3 g 1 mole of Cu atoms = 63.5 g So, Molar Mass is the atomic mass expressed in units grams/mole (g/mol) Chlorine has an atomic mass of 35.453 amu. So what is its molar mass? 35.453 grams per mole The number is the same, just change the unit. How do we find the molar mass of a compound? Find the molar mass of each element in the compound Determine how many of each element are in the compound. Multiply the number of each element by its molar mass. Add these mumbers. Aluminum Bromide AlBr3 In one mole of Aluminum Bromide, there is 1 mole of aluminum atoms and 3 moles of bromine atoms. To find the molar mass of AlBr3, we do the following: 1 mol Al x 26.9815 g/mol Al = 26.9815 g Al 3 mol Br x 79.904 g/mol Br = 239.712 g Br 26.9815 g Al + 239.712 g Br = 266.6935 g AlBr3 per mole or 266.6935 g/mol AlBr3 Where, n is the # of moles (mol) m is the mass (g) M is the molar mass (g/mol) What is the mass of 4.72 x 1023 formula units of chromium (III) iodide?