1. The Mole

2. What is a mole?  A conversion factor we use in chemistry to make it easier to talk about a very large amount of particles of elements or compounds  1 dozen bagels = 12 bagels  1 mole bagels = 6.02 x 10 23 bagels  A conversion factor we use in chemistry to make it easier to talk about a very large amount of particles of elements or compounds  1 dozen bagels = 12 bagels  1 mole bagels = 6.02 x 10 23 bagels

3. Avogadro’s Number  Avogadro’s # = 6.02 x 10 23 units  How does this number relate to a mole?  1 mole = 6.02 x 10 23 units *Units can be anything but in chemistry these units are referred to as:  Particles  Atoms  Molecules  Formula Units  Avogadro’s # = 6.02 x 10 23 units  How does this number relate to a mole?  1 mole = 6.02 x 10 23 units *Units can be anything but in chemistry these units are referred to as:  Particles  Atoms  Molecules  Formula Units

4. How big is 6.02 x 10 23 ?  Astronomers estimate that there is a mole of stars in the Universe.  One mole of high school textbooks would cover the USA to a depth of about 300 Km.  One mole of marshmallows would cover the USA to a depth of 105 000 Km.  One mole of moles placed to head to tail would stretch 11 million light years and weigh 9/10 as much of the moon.  One mole of pennies would make at least seven stacks that would reach the moon.  One mole of watermelon seeds would be found inside a melon slightly larger than the moon.  Astronomers estimate that there is a mole of stars in the Universe.  One mole of high school textbooks would cover the USA to a depth of about 300 Km.  One mole of marshmallows would cover the USA to a depth of 105 000 Km.  One mole of moles placed to head to tail would stretch 11 million light years and weigh 9/10 as much of the moon.  One mole of pennies would make at least seven stacks that would reach the moon.  One mole of watermelon seeds would be found inside a melon slightly larger than the moon.

5. Examples  1 mole Fe = 6.02 x 10 23 atoms Fe  1 mole C 12 H 22 O 11 = 6.02 x 10 23 molecules C 12 H 22 O 11  1 mole Al = 6.02 x 10 23 atoms Al  1 mole BeF 2 = 6.02 x 10 23 formula units BeF 2  1 mole Fe = 6.02 x 10 23 atoms Fe  1 mole C 12 H 22 O 11 = 6.02 x 10 23 molecules C 12 H 22 O 11  1 mole Al = 6.02 x 10 23 atoms Al  1 mole BeF 2 = 6.02 x 10 23 formula units BeF 2

6. How is the mole measured in the lab?  It is impossible to count up individual particles of chemicals in the lab because of their small size  We must find another way to measure 6.02 x 10 23 particles of a substance  It is impossible to count up individual particles of chemicals in the lab because of their small size  We must find another way to measure 6.02 x 10 23 particles of a substance

7. How does mass relate to the mole?  What does an amu (atomic mass unit) measure? 1 amu = 1.66053886 × 10 -27 kilograms  A relative scale used to measure the mass of single elements or compounds  What does an amu (atomic mass unit) measure? 1 amu = 1.66053886 × 10 -27 kilograms  A relative scale used to measure the mass of single elements or compounds

8. Learning the termonology… Atomic Mass  Atomic Mass - measures the mass of a single atom in amu’s  Example: 1 atom Fe = 55.85 amu  *Always go to the hundredths place when taking measurements from the periodic table  Atomic Mass - measures the mass of a single atom in amu’s  Example: 1 atom Fe = 55.85 amu  *Always go to the hundredths place when taking measurements from the periodic table

9. Formula Mass  Formula Mass - measures the mass of a single formula unit (ionic compound) in amu’s  Example: 1 formula unit BeF 2 = 1Be9.01 amu + 2F2(19.00 amu) = 47.01 amu  Formula Mass - measures the mass of a single formula unit (ionic compound) in amu’s  Example: 1 formula unit BeF 2 = 1Be9.01 amu + 2F2(19.00 amu) = 47.01 amu

10. Molecular Mass  Molecular Mass - measures the mass of a single molecule in amu’s  Example: 1 molecule C 12 H 22 O 11 = 12 C atoms 12(12.01 amu) + 22 H atoms22(1.01 amu) + 11 O atoms11(16.00 amu) = 342.34 amu  Molecular Mass - measures the mass of a single molecule in amu’s  Example: 1 molecule C 12 H 22 O 11 = 12 C atoms 12(12.01 amu) + 22 H atoms22(1.01 amu) + 11 O atoms11(16.00 amu) = 342.34 amu

11. Molar Mass  The mass of 1 mole of any substance in grams  Example: 1 atom Fe = 55.85 amu 1 mole (6.02 x 10 23 atoms) Fe = 55.85 g 1 molecule C 12 H 22 O 11 = 342.34 amu 1 mole (6.02 x 10 23 molecules) C 12 H 22 O 11 = 342.34 g  The mass of 1 mole of any substance in grams  Example: 1 atom Fe = 55.85 amu 1 mole (6.02 x 10 23 atoms) Fe = 55.85 g 1 molecule C 12 H 22 O 11 = 342.34 amu 1 mole (6.02 x 10 23 molecules) C 12 H 22 O 11 = 342.34 g

12. What is a representative particle?  The smallest particle that represents the true identity of the entire substance without altering it’s characteristics or properties  Example: What is the representative particle of 52 Al atoms?  The smallest particle that represents the true identity of the entire substance without altering it’s characteristics or properties  Example: What is the representative particle of 52 Al atoms?

13. Answer: 1 atom Al Example: What is the representative particle of 1 molecule of BeF 2 ? Answer: 1 atom Al Example: What is the representative particle of 1 molecule of BeF 2 ?

14.  Answer: 1 molecule BeF 2  1 atom of Be or 1 atom of F would not truly represent the properties and characteristics of BeF 2  Answer: 1 molecule BeF 2  1 atom of Be or 1 atom of F would not truly represent the properties and characteristics of BeF 2