THE MOLE(2’56”video: “The Mole and Conversion Methods”)

What is the mole?

We’re not talking about this kind of mole!

What is the Mole?◦A counting number (like a dozen)

◦1 mole = 6.02 1023 (602 billion trillion) things

◦Avogadro’s Number

(NA = 602,213,670,000,000,000,000,000)

A large amount!!!!

1 mole of hockey pucks would equal the mass of the moon!

1 mole of basketballs would fill a bag the size of the earth!

1 mole of pennies would cover the Earth 1/4 mile deep!

Counting Units◦1 dozen = 12 objects (eggs/donuts)

◦1 pair = 2 items (socks/shoes)

◦1 hour = 60 minutes

◦1 mole = 6.021023 things (atoms/molecules/formula units)

Practice! ◦If I have 1 mole of marshmallows, how many do I have?

◦If I have 2 moles of jelly beans, how many do I have?

◦If I have 6.02 x 1023 pennies, how many do I have?

6.02 X 1023 Marshmallows

2 moles 6.02 x 1023 jelly beans

1 mole

= 1.2 x 1024 jelly beans

1 mole of pennies

Why 6.02 1023 ?= The number of Carbon atoms in 12 grams of Carbon-12

Masses

◦Atomic Mass: mass of 1 atom of any element (unit: amu)

◦Molar Mass: mass of 1 mole of atoms / molecules (unit: gram)

From the Periodic Table, 1 Carbon atom weighs 12 amu’s

1 mole of Carbon atoms weighs 12 grams

Calculating Molar Mass for Compounds◦Add the Molar Masses of each atoms in a compound

◦e.g. Calculate the formula mass of Magnesium Carbonate, MgCO3.

24.31 g + 12.01 + 3 (16.00 g) = 84.32 g/mol

Examples for Molar Masses of Compounds1. Water

H2O

2(1.01) + 16.00 = 18.02 g/mol

2. Sodium chloride

NaCl

22.99 + 35.45 = 58.44 g/mol