The MOLEThe MOLE

The Center of the Chemical The Center of the Chemical UniverseUniverse

The MoleThe 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 MOLEThe MOLE• IS a counting unit for chemistry.

• A mole is 6.022 x 1023 atoms or molecules.

• We need a big number because atoms and molecules are so small.

• What if……..we counted regular items in moles????????

THE MOLE!!!!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!!!!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 TableAvogadro and The Periodic Table

• Avogadro (not avocado) was the one who calculated the mole number 6.022 x 1023 .

Lithium

6.941

Li3

The average atomic mass (6.941) has TWO roles in chemistry. FIRST, it tells themass of ONE ATOM in amu (atomicmass units). It also tells the massof ONE MOLE of atoms in GRAMS!This is very useful to us…we call itMOLAR MASS. There are no amuscales, only gram scales.

MOLAR MASSMOLAR 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!THE END!

Time to practice Conversions!