1.  Molar Mass

2. ATOMIC MASS  Mass of an atom in atomic mass units (amu)  Ex: Carbon = 12.01 amu  Molecular mass—sum of atomic masses (in amu) in the molecule  Ex: Water = 2 (1.01 amu) + 16.00 amu = 18.02 amu  Formula mass—sum of the atomic masses (in amu) in the formula unit of an ionic compound  EX: sodium chloride = 22.99 amu + 35.45 amu = 58.44amu

3. MOLAR MASS  Mass (in grams) of 1 mole of particles of a substance  Numerically equal to the atomic mass  Ex: water = 18.02 g C 8 H 11 NO 2 = magnesium phosphate =

4. Dimensional Analysis Examples i. Calculate the mass in grams of 0.0450 moles of chromium.

5. ii. What is the mass of 4.35 moles of sulfuric acid H 2 SO 4 ?

6. iii. Calculate the number of moles of 321 g of lead(II) chloride.

7. iv. How many formula units are in 124 g of mercury(II) chloride?

8. v. What is the mass in grams of 1.50×10 15 molecules of sulfur dioxide?

9. vi. A sample of aluminum chloride has a mass of 35.6 g. 1. How many moles of chloride ions are present? 1. How many chloride ions are present

10. vii. How many oxygen atoms are in 37.5 grams of SO 3 ?