Unit 3 SCH 3U

What is a Mole?  A small rodent-like animal that burrows underground  A double-agent  A dark growth on a person’s body  It is all of these things and more…

The Chemist’s Dozen  How many in a couple?  How many in a few?  How many in a dozen?  How many in a ream?

The Chemist’s Dozen  The mole is the chemist’s dozen  1 mole = 6.02 x particles  That is 602 sextillion  Or   This is called Avogadro’s number

Avogadro’s Number  Like a dozen, a mole is used to measure the amount of a substance.  If you have 1 dozen donuts, you have 12 donuts.  If you have 1 mole of donuts, you have 6.02 x donuts x donuts.  In chemistry, the mole is commonly used to count atoms, ions, formula units and molecules.

How Big Is It?  If you could travel at the speed of light, how long would it take to travel 6.02 x miles?  It would take more than 100 billion years to travel a mole of miles.

 How long would it take for 6.02 x drops of water to pass over Niagara Falls?  years years How Big Is It?

 If one mole of dollars were divided among six billion people on Earth, how much money would each person have?  Each person would have enough money to spend a million dollars every minute day and night for as long as we lived and still have more than half of it left.

The Mole and the Number of Particles  One mole of a substance is the amount of a substance containing 6.02 x particles of that substance.  1 mole of Na is 6.02 x atoms  1 mole of Cl 2 is 6.02 x molecules  1 mole of NaCl is 6.02 x formula units 6.02 x is Avogadro’s Number and is given the symbol N A.

 To calculate the number of particles in a sample of a substance we use the relationship: The Mole and the Number of Particles N = n N A Where N is the number of particles (atoms, molecules, formula units) n is the number of moles (mol) n is the number of moles (mol) N A is Avogadro’s number (atoms/mol, molecules/mol, formula units/mol) N A is Avogadro’s number (atoms/mol, molecules/mol, formula units/mol)

Finding the Number of Particles  How many atoms are represented by 2.6 mol of Fe?

Finding the Number of Moles  How many moles are present in a sample containing 5.63 x molecules of H 2 O?

Finding the Number of Atoms in a Sample  How many atoms of hydrogen are present in a sample containing 8.63 mol of methane, CH 4 ?

Time to Work  Pg 230 #11,13,15, 18, 20  Pg 231 #21, 24, 26, 27

The Mole and Mass  The molar mass of a substance is the mass of 6.02 x particles of that substance.  The molar mass of an element is equal to the atomic mass in g/mol.  The molar mass of a compound is equal to the sum of the atomic mass of all the elements present in g/mol.

Molar Mass  Find the molar mass of:  FePt  C 12 H 22 O 11 Ca(NO 3 ) 3

Relating Moles to Mass  To calculate the mass represented by a certain number of moles of a substance, we use the relationship:  Where n= moles (mol) m = mass (g) M = molar mass (g/mol) m = n M

Finding moles…  How many moles are represented by 56.2g of Cu?

Finding Mass…  Calculate the mass of 6.72 mol of Na 2 CO 3.

Time to Work  Pg 237 # 41, 43, 46, 49  Pg 239 # 54, 56, 57, 60