1. The Mole Theory Molar Mass

2. Mass of a Mole o Molar Mass- the mass of a mole of any element or compound (in grams) o Also called: o Formula mass – sum of the atomic masses of all the atoms in a formula of a compound o 1 Mole = Molar Mass o Conversion Factors: 1 MoleORMolar Mass Molar mass1 Mole

3. How to determine molar mass - The atomic mass expressed in grams- rounded to whole number (ones place) Examples:  C =  Cl =  O =  F = 12g 35g 16g 19g Take the Average Atomic Mass of the element from the periodic table and round to the nearest whole number – this is the Mass Number of that element

4. For compounds- Add together all the atoms that make up the compound Examples: SO 3 = How to determine molar mass- 1 S atom  3 O atoms 32g + 16g + 16g + 16g = 80g

5. What is the gram formula mass of ammonium carbonate (NH 4 ) 2 CO 3 ? Take inventory: ◦ N- 2 × 14g = 28g ◦ H- 8 × 1g = 8g ◦ C- 1 × 12g= 12g ◦ O- 3 × 16g = 48g 96g (NH 4 ) 2 CO 3 How to determine molar mass- I call this ‘Side Work’ – it is often not our main purpose, but we need it to finish the job