1. Matter Unit

2.  A unit created to describe atoms because the gram and kilogram are too large to use to define an atom.  1amu = 1.66 x 10 -24 g .00000000000000000000000166g

3.  Listed on the periodic table as the atomic mass.  The average mass of all of the isotopes of an atom. Elementamu Hydrogen1.008 Carbon12.01 Nitrogen14.01 Oxygen16.00 Sodium22.99 Aluminum26.98

4.  1 atom = 1 amu  Example › 1 atom of carbon = 12.001 amu of carbon › 3 atoms of carbon = 36.003 amu of carbon › 3.00 X 10 20 amu =2.50 x 10 19 atoms of carbon

5.  The unit all chemists use in describing numbers of atoms.  Defined as the number equal to the number of carbon atoms in 12.01 grams of carbon.  A sample of on element with a mass equal to that element’s average atomic mass expressed in grams contains 1 mol of atoms.

6.  6.022 X 10 23  One mole of something consists of 6.022 X 10 23 units of that substance. › One mole of eggs is 6.022 X 10 23 of eggs. Elements# of atoms Mass of sample (g) Aluminum6.022 X 10 23 26.98 Gold6.022 X 10 23 196.97 Iron6.022 X 10 23 55.85 Sulfur6.022 X 10 23 32.07 Boron6.022 X 10 23 10.81 Xenon6.022 X 10 23 131.3

7.  The mass of one mole of a substance. › The sum of all the masses of the atoms in a compound. CH 4 C - 1x12.01=12.01 H – 4x1.008=4.032 Total = 16.04g

8. 6.02 x 10 23 particles 1 mole or 1 mole 6.02 x 10 23 particles Note that a particle could be an atom OR a molecule! Avogadro’s Number as Conversion Factor

9. molar mass Grams Moles Calculations with Molar Mass

10. Aluminum is often used for the structure of light-weight bicycle frames. How many grams of Al are in 3.00 moles of Al? 3.00 moles Al ? g Al Converting Moles and Grams

11. 1. Molar mass of Al1 mole Al = 27.0 g Al 2. Conversion factors for Al 27.0g Al or 1 mol Al 1 mol Al 27.0 g Al 3. Setup3.00 moles Al 27.0 g Al 1 mole Al Answer = 81.0 g Al