Transcript The MOLE

The MOLE
The Center of the Chemical
Universe
The Mole
• Does NOT refer to a small woodland animal who
lives in underground tunnels
• Does NOT refer to a pigment-enhanced area of skin
• Does NOT refer to an informant placed inside an
organization
• Does NOT refer to a Mexican cooking sauce
• DOES refer to the MOST IMPORTANT COUNTING
UNIT OF….ALL….TIME!!!!!
The MOLE
• IS a counting unit for chemistry.
• A mole is 6.022 x 10 atoms or molecules.
• We need a big number because atoms
and molecules are so small.
• What if……..we counted regular items in
moles????????
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THE MOLE!!!!
• If there was actually a mole of pennies,
and we divided it equally worldwide, you
would have to spend 1 million dollars each
day to use up your share……
THE MOLE!!!!
• BUT YOU WOULD HAVE TO LIVE TO BE
4000 YEARS OLD TO USE UP YOUR
MONEY!!!!!!!!!!!!!
• Do you think there is a mole of SAND
particles on Earth?????? (based on
coastline miles and desert size???)
• ALMOST. NOW………………would you
like to see a mole of water molecules????
Avogadro and The Periodic Table
• Avogadro (not avocado) was the one who
calculated the mole number 6.022 x 10 .
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Lithium
6.941
3
Li
The average atomic mass (6.941) has TWO
roles in chemistry. FIRST, it tells the
mass of ONE ATOM in amu (atomic
mass units). It also tells the mass
of ONE MOLE of atoms in GRAMS!
This is very useful to us…we call it
MOLAR MASS. There are no amu
scales, only gram scales.
MOLAR MASS
• Finding the Molar Mass of an element is easy.
1. Find the element on the PT
2. Write down the mass
3. add the unit g/mol
NOW you have TWO pieces of info--the mass in amu of one atom
the mass of a MOLE of that atom in grams!
THE END!
Time to practice
Conversions!