11/28/2011

Post date: Nov 29, 2011 7:21:31 PM

• Bell Ringer:

  • Molar mass notes

    • a mole is a counting unit, similar to a dozen or a gross in baking. We use moles in chemistry to describe the number of atoms. 1 mole = 602,000,000,000,000,000,000,000 of something.

    • Molar mass - the mass of one mole of an element or compound

    • Molar mass for elements can be found on the periodic table at the mass number on the bottom of each entry. For example, 1 mole of hydrogen atoms has a mass of 1.0079 grams

    • Molar mass for compounds must be calculated by adding the molar masses for each atom in the compound (we usually round the masses off to whole numbers)

      • example: H20 has 3 molecules: 2 Hydrogens and 1 Oxygen. The molar mass of H2O is the MM of H + MM of H + MM of O, or 1 + 1 + 16 = 18.

  • Molar Mass assignment: Find the molar mass for each compound

    • 1. SiCl4

    • 2. NaOH

    • 3. V2O5

    • 4. NaCl

    • 5. Mg3N2