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Could you determine the amount of atoms in a substance?PowerPoint Presentation

Could you determine the amount of atoms in a substance?

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Could you determine the amount of atoms in a substance?

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Could you determine the amount of atoms in a substance?

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Could you determine the amount of atoms in a substance?

How do scientists count when atoms and molecules are so small?

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

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

- 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…..

- 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

- 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

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 H2O, HF

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

- 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

- 2.3 mols of Sr
- 2.3 mols 6.02 X 10 23 atoms/1 mol = 1.4 X 10 24 atoms

- 345 g of Ca
- 345 g Ca 1 mol/40.078g 6.02 X 10 23 atoms/1 mol