 ## Presentation on theme: "All Roads Lead to the Mole"— Presentation transcript:

Chemical Quantities Dozen: Baker as Mole: Chemist Measuring donuts:
1 dozen = 12 donuts (count) 1 dozen = 500 g donuts (mass) 1 dozen = 1 box donuts (volume) Measuring steam (H2O gas): 1 mole = 6.02 x 1023 H2O molecules (count) 1 mole = 18.0 g H2O (mass) 1 mole = 22.4 L H2O (volume) at STP

Lawyer who became interested in math and physics Discovered that equal volumes of different gases contained an equal number of particles. 9 years after his death, Joseph Loschmidt determined a constant and named it after Avogadro.

Not to be confused with the delicious fruit
AVOGADRO’S CONSTANT = 6.02 x 1023 Not to be confused with the delicious fruit

AVOGADRO’S CONSTANT = 6.02 x 1023
1 mole = 6.02 x 1023 particles 1 mole = molar mass (grams) 1 mole (of a gas at STP) = 22.4 L

The mole is to chemists as the dozen is to bakers.

A Mole Balance

Believe it or not, students all over the country celebrate National Mole Day!
National Mole Day Foundation, INC. Mole Day

How BIG is a MOLE? 5 Pound Bag of Sugar contains 6.6 moles Of C12H22O11 1 Liter bottle of Water contains 55.5 moles H20 6.02 x 1023 Grains of Sand: Would be more than all of the sand on Miami Beach. 6.02 x 1023 Blood Cells: Would be more than the total number of blood cells found in every human on earth. 6.02 x 1023 Watermelon Seeds: Would be found inside a melon slightly larger than the moon. 6.02 x 1023 Pennies: Would make at least 7 stacks that would reach the moon. 6.02 x 1023 Donut Holes: Would cover the earth and be 5 miles (8 km) deep.

...AND YOUR UNITS WILL CARRY YOU!
Draw on NOTETAKERS (and pass out flow Mole Map) CARRY YOUR UNITS... Volume Mass MOLE R.P. Formula Units Ions Molecules Atoms ...AND YOUR UNITS WILL CARRY YOU!

Types of Representative Particles
Molecules (break down into atoms) Atoms Formula Units (break down into ions) Ions

Naming Representative Particles
Pure Substance Element Monotomic Charged ION Neutral ATOM Polyatomic MOLECULE Compound Molecular Ionic FORMULA UNIT

Naming Representative Particles
Examples: Name the representative particle for each substance given. For each molecule, state how many atoms are present. For each formula unit, state how many ions make up the ionic compound. H+: Cl2: C2H6: Cu(NO3)2: Al: NaCl: ION MOLECULE – 2 ATOMS per molecule MOLECULE – 8 ATOMS FORMULA UNIT – 3 IONS per Form.U. ATOM FORMULA UNIT – 2 IONS per Form.U.

WS: Representative Particles
Do WS #1-20

1 mole = Avogadro’s Number = 6.02 x 1023 R.P.’s
Mole R.P. Calculations 1 mole = Avogadro’s Number = 6.02 x 1023 R.P.’s R.P. MOLE

R.P. Example 1: How many moles are in 1.4 x 1022 molecules of H2O?

R.P. Example 2: How many representative particles are in 2.6 mol CO2?

R.P. Example 3: How many atoms are in 5.2 mol CO2?

DO WS: The Mole and Avogadro’s Number

MOLAR MASS The molar mass is the mass, in grams, of one mole (6.02  1023 particles) of an element (ion), a covalent molecule or a formula unit. molar mass (MM) gram atomic mass (gam) molecular weight (MW) gram molecular mass (gmm) formula mass (FM) gram formula mass (gfm) formual weight (FW)

MASS of one MOLE Gram atomic mass (gam): the atomic mass (the mass in one mole of a substance) of an element expressed in grams. Gram molecular mass (gmm): the atomic mass of one mole of a molecular compound. Gram formula mass (gfm): the sum of the atomic masses of the atoms that are in the formula of a compound.

gam, gfm, gmm examples: Problem: Give the gram atomic mass of hydrogen. Solution: H = 1H = 1(1.01) = 1.01 g/mol Problem: Give the gram molecular mass of hydrogen. Solution: H2 = 2H = 2(1.01) = 2.02 g/mol Problem: Find the gram formula mass for H2SO4. Solution: H2SO4 = 2H + 1S + 4O = 2(1.01) (16.00) = g/mol

Molar Mass … a.k.a. Molecular Weight (MW)
molar mass = mass of 1 mole of substance Molar mass can be determined by adding up the atomic masses from the periodic table (atomic mass goes to 2 decimal places).

MW Example 1: = 1C + 4H = 12.01 + 4(1.01) = 16.05 g CH4/mol CH4
Find the MW of CH4. = 1C + 4H = (1.01) = g CH4/mol CH4

MW Example 2: =Mg + 2O + 2H =24.31 + 2(16.00) + 2(1.01)
Find the MW of Mg(OH)2. =Mg + 2O + 2H = (16.00) + 2(1.01) =58.33 g Mg(OH)2 /mol Mg(OH)2

MW Example 3: Find the MW of MgSO4∙7H2O. =Mg + S + 4O + 7(H2O)
= (16.00) + 7( ) = g MgSO4∙7H2O /mol MgSO4∙7H2O

Calculations: Use Mole Map to help calculate

Mole Mass Calculations
1 mole = molar mass (MW) in grams Mass MOLE

Mass Example 1: How many grams are in 7.20 moles of dinitrogen trioxide? dinitrogen trioxide = N2O3 MW of N2O3 = 2N + 3O = 2(14.01) + 3(16.00) = g/mol 1 mole = g N2O3

MW of Fe2O3 = 2Fe + 3O = 2(55.85) + 3(16.00) = 159.70 g/mol
Mass Example 2: Find the number of moles in 92.2 g of iron(III) oxide. iron(III) oxide = Fe2O3 MW of Fe2O3 = 2Fe + 3O = 2(55.85) + 3(16.00) = g/mol 1 mole = g Fe2O3

Make sure you write out all work and include all units!!
Practice Worksheet Do #1-10 on Mole and Mass WS Make sure you write out all work and include all units!!

Mole Volume Calculations
1 mole = 22.4 L of gas at STP STP = standard temperature and pressure (0 °C & 1 atm) Volume MOLE

Volume Example 1: Determine the volume, in liters, of mol of SO2 gas at STP.

Volume Example 2: Determine the number of moles in 33.6 L of He gas at STP.

Density density = mass / Volume
When given the density of an unknown gas, one can multiply by the molar volume to find the MW. The MW can allow for identification of the gas from a list of possibilities.

Density Example (part A):
The density of an unknown gas is g/L at STP. (a) What is the molar mass?

Density Example (part B):
The density of an unknown gas is g/L (b) Identify the gas as either nitrogen, fluorine, nitrogen dioxide, carbon dioxide, or ammonia. MW = g/mol (from part a) Nitrogen = N2 = 2(14.01) = g/mol Fluorine = F2 = 2(19.00) = g/mol Nitrogen dioxide = NO2 = (16.00) = g/mol Carbon dioxide = CO2 = (16.00) = g/mol Ammonia = NH3 = (1.01) = g/mol

Mixed Mole Conversions
1 mole = x 1023 RP’s = MW = L of All Roads Lead to the Mole. Always convert to units of moles first when converting between grams, liters, and representative particles.

Mixed Mole Example 2: How many atoms are in 22.0 g of water?
22.0 g H2O × 1 mole H2O g H2O × 6.02×1023 molec. H2O 1 mole H2O × 3 atoms 1 molec. H2O

Mixed Mole Example 1: How many carbon atoms are in a 50.0-carat diamond that is pure carbon? Fifty carats is the same as 10.0 g.

Extra questions to review concepts

What is the mass of one mole of table salt (NaCl)?
23.0 g 35.5 g 58.44 g 100.0 g atomic mass Na = g/mol atomic mass Cl = g/mol mass of one mole of NaCl = = g

What is the mass of 3.7 moles of NaCl?
15.8 g 58.5 g 220 g 6.02 x 1023 g

What is the mass of one mole of water (H2O)?
3.0 g 16.0 g 17.0 g 18.02 g atomic mass H = 1.01 g/mol atomic mass O = g/mol mass of one mole of H2O = 2(1.01) = g

How many moles are in 152 g of water?
6.02 x 1023 mol