The Mole and Molar Mass

Remember: 1 mole = 6.02 x 1023 particles The mass on the periodic table is correct for one atom in a.m.u. AND for 1 mole of that element in grams 6.02 x 1023 is the number of atoms contained in the atomic masses of each element on the periodic table Ex: 1 mole oxygen = 6.02 x 1023 particles of O = 16.00 g of oxygen

Realize that a mole refers to the number of particles, not a mass. A mole of sulfur then will have a different mass than a mole of Lead. Since their atoms have difference sizes and masses, the overall masses can vary greatly.

Think about the Dozen… Which dozen eggs will have the greatest mass? They all have the same number of eggs! Albatross Chicken Robin Chicken Ostrich Emu

Molar Mass Molar Mass: The mass in grams of 1 mol of a substance. This is equal to the atomic mass (amu) of the element Symbol: M Units: ( g / mol ) (grams/mole)

Ex: Determine the molar mass of H2O MH2O = 2(M for H) + (M of O) = 2(1.01 g/mol) + (16.00 g/mol) = 18.02 g/mol Ex: Determine the molar mass of Ca(NO3)2 MCa(NO3)2 = (M of Ca) + 2(M of N) + 6(M of O) = (40.08 g/mol) + 2(14.01 g/mol) + 6(16.00 g/mol) = 164.10 g/mol

Your new best friend… The Mole formula! Be able to rearrange it to solve for each of the variables! n = m M mass (g) Number of moles (mol) Molar mass (g/mol)

Practice …