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

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

Using the concept of Using the concept of counting by weight counting by weight

Could you determine Could you determine the amount of atoms in the amount of atoms in

a piece of copper?a piece of copper?

What information would What information would you need?you need?

The periodic table has a The periodic table has a secret! It can tell you the secret! It can tell you the

amount of atoms in a specific amount of atoms in a specific mass of each elementmass of each element

Look at the amu of copper. The amu Look at the amu of copper. The amu also describes the number of atoms also describes the number of atoms in a specific mass in gin a specific mass in g

Ex: There are 6.02 X10 Ex: There are 6.02 X10 2323 atoms/63.546 g of copperatoms/63.546 g of copper

Could you determine the amount of Could you determine the amount of atoms in any piece of Copper?atoms in any piece of Copper?

Go ahead…..Go ahead…..

6.02 X10 6.02 X10 2323 is a huge number!!! is a huge number!!! It is a unit of measurement that scientists use. It is a unit of measurement that scientists use.

Just as chefs use the dozen (12)Just as chefs use the dozen (12) This is manageable because atoms are so tinyThis is manageable because atoms are so tiny They call this number a mole!! (sometimes They call this number a mole!! (sometimes

abbreviated mol)abbreviated mol) With this new information could you determine With this new information could you determine

the amount of moles if I gave you a specific mass the amount of moles if I gave you a specific mass of an element? of an element?

Write a conversion you could use.Write a conversion you could use. Ex If I have .500g Al 1mol/26.98g How many Ex If I have .500g Al 1mol/26.98g How many

mols do I have try it…mols do I have try it… .500g Al 1 mol/26.98g = .0185 mols of Al.500g Al 1 mol/26.98g = .0185 mols of Al

If I gave you the amount of mols could you give If I gave you the amount of mols could you give me the mass?me the mass?

.496 mols of Al 26.98g Al/1 mol = 13.4 g Al.496 mols of Al 26.98g Al/1 mol = 13.4 g Al If I gave you the number of atoms could you If I gave you the number of atoms could you

determine the mass?determine the mass? Remember there are 6.02 X10 Remember there are 6.02 X10 23 23 atoms in a mol atoms in a mol

and the molar mass is the mass of one moleand the molar mass is the mass of one mole Find the mass of 2.03 X10 Find the mass of 2.03 X10 23 23 atoms of Satoms of S 2.03 X10 2.03 X10 2323 atoms S 1 mol/6.02 X 10 atoms S 1 mol/6.02 X 10 23 23 atoms S atoms S

32.055g S/1 mol 32.055g S/1 mol Answer = 10.8 g SAnswer = 10.8 g S

The number on the periodic table is The number on the periodic table is called the MOLAR MASS. This gives called the MOLAR MASS. This gives you the mass in one mole of a you the mass in one mole of a substance.substance.

Find the molar mass of O,S,N,FFind the molar mass of O,S,N,F

Find the molar mass of HFind the molar mass of H22O, HFO, HF

Can you find the mass of a Can you find the mass of a particular amount of atoms?particular amount of atoms?

Find the mass of 2.03 X10 Find the mass of 2.03 X10 23 23 atoms of atoms of SS

2.03 X10 2.03 X10 2323 atoms S 1 mol/6.02 X 10 atoms S 1 mol/6.02 X 10 23 23 atoms S 32.055g S/1 mol atoms S 32.055g S/1 mol

Answer = 10.8 g SAnswer = 10.8 g S

Moles from Atoms?Moles from Atoms?

Could you determine the amount of Could you determine the amount of moles if I gave you the amount of moles if I gave you the amount of atoms?atoms?

3.02 X 10 3.02 X 10 2323 atoms of Ca is how many atoms of Ca is how many moles?moles?

3.02 X10 3.02 X10 23 23 atoms Ca 1 mol/ 6.02 X atoms Ca 1 mol/ 6.02 X 10 10 2323 atoms Ca = .502 mols Ca atoms Ca = .502 mols Ca

Could you determine the amount of Could you determine the amount of atoms in a specific amount of atoms in a specific amount of

moles?moles? 2.3 mols of Sr2.3 mols of Sr 2.3 mols 6.02 X 10 2.3 mols 6.02 X 10 2323 atoms/1 mol = atoms/1 mol =

1.4 X 10 1.4 X 10 24 24 atomsatoms

How about the number of atoms in How about the number of atoms in a specific amount of mass?a specific amount of mass?

345 g of Ca345 g of Ca 345 g Ca 1 mol/40.078g 6.02 X 10 345 g Ca 1 mol/40.078g 6.02 X 10 2323

atoms/1 molatoms/1 mol