Matter Unit

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

 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

 1 atom = 1 amu  Example › 1 atom of carbon = amu of carbon › 3 atoms of carbon = amu of carbon › 3.00 X amu =2.50 x atoms of carbon

 The unit all chemists use in describing numbers of atoms.  Defined as the number equal to the number of carbon atoms in 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.

 X  One mole of something consists of X units of that substance. › One mole of eggs is X of eggs. Elements# of atoms Mass of sample (g) Aluminum6.022 X Gold6.022 X Iron6.022 X Sulfur6.022 X Boron6.022 X Xenon6.022 X

 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

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

molar mass Grams Moles Calculations with Molar Mass

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

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