1.  Could you determine the amount of atoms in a substance?  How do scientists count when atoms and molecules are so small?

2. Using the concept of counting by weight Could you determine the amount of atoms in a piece of copper?

3. What information would you need? The periodic table has a secret! It can tell you the amount of atoms in a specific mass of each element

4.  Look at the amu of copper. The amu also describes the number of atoms in a specific mass in g  Ex: There are 6.02 X10 23 atoms/63.546 g of copper  Could you determine the amount of atoms in any piece of Copper?  Go ahead…..

5.  6.02 X10 23 is a huge number!!!  It is a unit of measurement that scientists use. Just as chefs use the dozen (12)  This is manageable because atoms are so tiny  They call this number a mole!! (sometimes abbreviated mol)  With this new information could you determine the amount of moles if I gave you a specific mass of an element?  Write a conversion you could use.  Ex If I have.500g Al 1mol/26.98g How many mols do I have try it… .500g Al 1 mol/26.98g =.0185 mols of Al

6.  If I gave you the amount of mols could you give me the mass? .496 mols of Al 26.98g Al/1 mol = 13.4 g Al  If I gave you the number of atoms could you determine the mass?  Remember there are 6.02 X10 23 atoms in a mol and the molar mass is the mass of one mole  Find the mass of 2.03 X10 23 atoms of S  2.03 X10 23 atoms S 1 mol/6.02 X 10 23 atoms S 32.055g S/1 mol  Answer = 10.8 g S

7.  The number on the periodic table is called the MOLAR MASS. This gives you the mass in one mole of a substance.  Find the molar mass of O,S,N,F  Find the molar mass of H 2 O, HF

8. Can you find the mass of a particular amount of atoms?  Find the mass of 2.03 X10 23 atoms of S  2.03 X10 23 atoms S 1 mol/6.02 X 10 23 atoms S 32.055g S/1 mol  Answer = 10.8 g S

9. Moles from Atoms?  Could you determine the amount of moles if I gave you the amount of atoms?  3.02 X 10 23 atoms of Ca is how many moles?  3.02 X10 23 atoms Ca 1 mol/ 6.02 X 10 23 atoms Ca =.502 mols Ca

10. Could you determine the amount of atoms in a specific amount of moles?  2.3 mols of Sr  2.3 mols 6.02 X 10 23 atoms/1 mol = 1.4 X 10 24 atoms

11. How about the number of atoms in a specific amount of mass?  345 g of Ca  345 g Ca 1 mol/40.078g 6.02 X 10 23 atoms/1 mol