The Mass of a Mole of an Element Atomic mass of element (mass of 1 atom) expressed in amu

The Mass of a Mole of an Element Atomic mass of element (mass of 1 atom) expressed in amu atomic masses - relative masses based on mass of C-12 (12.0 amu) 1 amu is 1/12 mass of C-12 atom

Molar Mass…. All contain 6.02 x 1023 atoms = mass of 1 mol of element in grams (periodic table) 12.01 grams C has same # particles as 1.01 g H & 55.85 g Fe 12.01 g C = 1 mol C 1.01 g H = 1 mol H 55.85 g Fe = 1 mol Fe All contain 6.02 x 1023 atoms

What about compounds? 1 mol of H2O molecules has 2 mol of H atoms & 1 mol of O atoms (think of a compound as a molar ratio) To find mass of 1 mol of a cmpd: determine # moles of elements present Multiply # times their mass (from periodic table) add up for total mass

Calculating Molar Mass Calculate molar mass of magnesium carbonate, MgCO3. 84.3 g 24.3 g + 12.0 g + 3 x (16.00 g) = So, 84.3 g = molar mass for MgCO3

Practice problems Page 296 The decomposition of hydrogen peroxide (H2O2) provides sufficient energy to launch a rocket. What is the molar mass of hydrogen peroxide?

Independently do questions 7 and 8 on page 296.