The Mole What is a Mole?

The mole is a word that means a number, just like…  1 pair = 2 objects  1 dozen = 12 objects  1 score = 20 objects  1 gross = 144 objects  1 ream = 500 objects  1 mole = 6.02 x objects

The Mole  The mole is a unit  6.02 x particles  Avogadro’s Number  602,000,000,000,000,000,000,000 particles  The number of carbon atoms in exactly 12 grams of pure Carbon-12  Abbreviated as “mol.”

The Mole  A mole of marbles would cover the surface of the earth to a depth of more than 6 kilometers  A mole is equal to every gram of sand on every beach and ocean floor on the planet  If you were given 1 mole of dollars the day you were born and then spent a billion dollars a second for your entire life before dying at age 70, you would have only spent 0.001% of your money before you died.

The Mole  Why would we need a number so HUGE!?  Used to count particles  Atoms, molecules, and formula units  Used also to convert  This is where dimensional analysis comes in…OH YA!

MOLE – PARTICLE CONVERSIONS

The Mole  Conversion factors: 1 mole 6.02 x particles 1 mole 6.02 x particles

The Mole  Let’s start out with an easy one:  You have 3.5 dozen roses. How many roses do you have? 3.5 dozen roses 12 roses 1 dozen roses x = 42 roses

The Mole  Ok, let’s see a mole example  4.2 moles  molecules 4.2 moles 6.02 x x molecules 1 mole x = 2.5 x molecules

The Mole  Convert 4.56 x atoms to moles 4.56 x atoms 6.02 x x atoms 1 mole x = 7.57 moles

The Mole Perform the following conversions; don’t forget sig figs!  3.7 moles  atoms  2.2 x atoms  3.27 x molecules  moles  moles  moles  molecules  4.41 x molecules

More Practice 1.How many molecules are in 0.98 moles? 2.How many moles are in 4.75x10 24 molecules of hydrogen? 3.How many formula units are in 1.08 moles? 4.How many moles are in 9.12x10 18 molecules of carbon?

More Practice 1.How many molecules are in 0.98 moles? 5.9 x molecules 2.How many moles are in 4.75x10 24 molecules of hydrogen? 7.89 moles of H 2 3.How many formula units are in 1.08 moles? 6.50 x formula units 4.How many moles are in 9.12x10 18 molecules of carbon? 1.51 x moles of C

MOLAR MASS

Mole & Mass  Different elements have different masses  You can find the mass of an element by looking at the periodic table

Atomic Mass  Atomic Mass: the mass of one atom (in units of amu or atomic mass units)  Ex: Carbon 12.0 amu Neon 20.2 amu

Molar Mass  Molar Mass  The mass of ONE MOLE of a particular substance  Expressed in grams per mole (g/mol).

 Atomic Mass Vs Molar Mass The value of atomic masses and molar masses will be the same, the difference is the unit…  Formula mass for Cl is… 35.5  This is the mass of 1 ATOM of Cl  Molar mass for Cl is… 35.5  This is the mass of 1 MOLE (6.02x10 23 ) of atoms of Cl amu g/mol

Molar Mass of Compounds  #1: Find the molar mass of Ca(OH) 2  Step 1: List the individual elements in the compound Ca O H

Molar Mass of Compounds  Step 2: Determine the mass for each individual element (found on PT) Ca O = H =

Molar Mass of Compounds  Step 3: Multiply the masses by how many atoms you have of each element Ca = O = H = x 1 = 40.1 x 2 = 32.0 x 2 = 2.02

Molar Mass of Compounds  Step 4: Add up the masses to get the TOTAL molar mass Ca = O = H = x 1 = 40.1 x 2 = 32.0 x 2 = g/mol= 74.1 g/mol

Molar Mass of Compounds  Find the molar mass of Na 2 CO 3 Na = C = O = x 2 = 46.0 x 1= 12.0 x 3 = g/mol

Molar Mass of Compounds  Find the molar mass of the following:  AlCl 3  Ba 3 (PO 4 ) 2 = g/mol = g/mol

You Try! Find the molar mass 1.NO 2 2.2NO 2 3.Na 2 SO 4 4.C 6 H 12 O 6 5.4H 2 O 6.2KCl + 3O 2  2KClO 3

MASS – MOLE CONVERSIONS

Mass & Mole  Mass  Mole or Mole  Mass  Use Molar Mass (g/mol) and dimensional analysis.

Mass & Mole  Determine the number of moles in grams of water (H 2 O) g H2O 1 mole H2O g H2O x = moles H2O

Mass & Mole  How many grams of NaCl are in 2.37 moles? 2.37 mol NaCl 58.5 g NaCl 1 mol NaCl x = 139 g NaCl

You Try  Perform the following conversions:  moles LiF  grams  grams LiF  grams MgS  moles  moles MgS

MASS – PARTICLE CONVERSIONS

Mass – Particle Conversions  Converting from mass to number of particles is a two step conversion.  If you are starting with mass, you will first need to convert to moles, then to particles.  If you are starting in particles, you will first need to convert to moles, then to mass.

Mass – Particle Conversions Practice  If you have 6.2 grams of Calcium, how many atoms of calcium do you have?  There are 8.1 x atoms of sulfur in a sample. What would the mass of the sample be?

Mass – Particle Conversions of Compounds Practice  If you have 3.7 x molecules of strontium chloride, what would the mass of the sample be?  If you have a 4.19 gram sample of aluminum sulfate, how many molecules of aluminum sulfate do you have?

Mixed Practice 1)Convert 3.2 moles Cu to atoms of Cu. 2)Convert 56 g Al 2 O 3 to moles of Al 2 O 3 3)Convert 1.62x10 36 molecules of LiClO 3 to grams of LiClO 3 4)Convert 8.29 grams Pb to atoms of Pb

Mixed Practice 5)Convert 7.3 mol of S to grams of S 6)Convert 92 g of N 2 O to molecules of N 2 O 7)Convert 5.41 x molecules of H 2 O to moles of H 2 O 8)Convert 5.7 x atoms B to grams of B

Mixed Practice Answers 1)Convert 3.2 moles Cu to atoms of Cu. 1.9 x atoms Cu 2)Convert 56 g Al 2 O 3 to moles of Al 2 O moles Al 2 O 3 3)Convert 1.62x10 36 molecules of LiClO 3 to grams of LiClO x grams LiClO 3 4)Convert 8.29 grams Pb to atoms of Pb 2.41 x atoms Pb

Mixed Practice Answers 5)Convert 7.3 mol of S to grams of S 230 grams S 6)Convert 92g of N 2 O to molecules of N 2 O 1.3 x molecules of N 2 O 7)Convert 5.41 x molecules of H 2 O to moles of H 2 O 8.99 x 10 3 moles of H 2 O 8)Convert 5.7 x atoms B to grams of B 1.0 x 10 2 grams B