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/ 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 atoms S g 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 H 2 O, HF
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 atoms S g S/1 mol Answer = 10.8 g S
Moles from Atoms? Could you determine the amount of moles if I gave you the amount of atoms? 3.02 X atoms of Ca is how many moles? 3.02 X10 23 atoms Ca 1 mol/ 6.02 X atoms Ca =.502 mols Ca
Could you determine the amount of atoms in a specific amount of moles? 2.3 mols of Sr 2.3 mols 6.02 X atoms/1 mol = 1.4 X atoms
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 atoms/1 mol