Presentation on theme: "CHEMICAL QUANTITIES All Roads Lead to the Mole Chemical Quantities Measuring donuts: 1 dozen = 12 donuts (count) 1 dozen = 500 g donuts (mass) 1 dozen."— Presentation transcript:
CHEMICAL QUANTITIES All Roads Lead to the Mole
Chemical Quantities Measuring donuts: 1 dozen = 12 donuts (count) 1 dozen = 500 g donuts (mass) 1 dozen = 1 box donuts (volume) Measuring steam (H 2 O gas): 1 mole = 6.02 x H 2 O molecules (count) 1 mole = 18.0 g H 2 O (mass) 1 mole = 22.4 L H 2 O (volume) at STP Dozen: Baker as Mole: Chemist
Count Amedeo Avogadro 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.
AVOGADRO’S CONSTANT = 6.02 x Not to be confused with the delicious fruit
AVOGADRO’S CONSTANT = 6.02 x mole = 6.02 x 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.
Believe it or not, students all over the country celebrate National Mole Day! National Mole Day Foundation, INC. Mole Day
5 Pound Bag of Sugar contains 6.6 moles Of C 12 H 22 O 11 1 Liter bottle of Water contains 55.5 moles H x Grains of Sand: Would be more than all of the sand on Miami Beach x Blood Cells: Would be more than the total number of blood cells found in every human on earth x Watermelon Seeds: Would be found inside a melon slightly larger than the moon x Pennies: Would make at least 7 stacks that would reach the moon x Donut Holes: Would cover the earth and be 5 miles (8 km) deep.
MassVolume R.P. Molecules Atoms Formula Units Ions Draw on NOTETAKERS (and pass out flow Mole Map)
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 MOLECULE 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 + : Cl 2 : C 2 H 6 : Cu(NO 3 ) 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
Mole R.P. Calculations 1 mole = Avogadro’s Number = 6.02 x R.P.’s R.P.
R.P. Example 1: How many moles are in 1.4 x molecules of H 2 O?
R.P. Example 2: How many representative particles are in 2.6 mol CO 2 ?
R.P. Example 3: How many atoms are in 5.2 mol CO 2 ?
DO WS: The Mole and Avogadro’s Number
MOLAR MASS The molar mass is the mass, in grams, of one mole (6.02 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: H 2 = 2H = 2(1.01) = 2.02 g/mol Problem: Find the gram formula mass for H 2 SO 4. Solution: H 2 SO 4 = 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: Find the MW of CH 4. = 1C + 4H = (1.01) = g CH 4 /mol CH 4
MW Example 2: 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 MgSO 4 ∙7H 2 O. =Mg + S + 4O + 7(H 2 O) = (16.00) + 7( ) = g MgSO 4 ∙7H 2 O /mol MgSO 4 ∙7H 2 O
Calculations: Use Mole Map to help calculate
Mole Mass Calculations 1 mole = molar mass (MW) in grams Mass
Mass Example 1: How many grams are in 7.20 moles of dinitrogen trioxide? MW of N 2 O 3 = 2N + 3O = 2(14.01) + 3(16.00) = g/mol 1 mole = g N 2 O 3 dinitrogen trioxide = N 2 O 3
Mass Example 2: Find the number of moles in 92.2 g of iron(III) oxide. MW of Fe 2 O 3 = 2Fe + 3O = 2(55.85) + 3(16.00) = g/mol 1 mole = g Fe 2 O 3 iron(III) oxide = Fe 2 O 3
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
Volume Example 1: Determine the volume, in liters, of mol of SO 2 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 = N 2 = 2(14.01) = g/mol Fluorine = F 2 = 2(19.00) = g/mol Nitrogen dioxide = NO 2 = (16.00) = g/mol Carbon dioxide = CO 2 = (16.00) = g/mol Ammonia = NH 3 = (1.01) = g/mol
Mixed Mole Conversions 1 mole = 6.02 x RP’s = MW = 22.4 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?
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)? a)23.0 g b)35.5 g c)58.44 g d)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? a)15.8 g b)58.5 g c)220 g d)6.02 x g
What is the mass of one mole of water (H 2 O)? a)3.0 g b)16.0 g c)17.0 g d)18.02 g atomic mass H = 1.01 g/mol atomic mass O = g/mol mass of one mole of H 2 O = 2(1.01) = g
How many moles are in 152 g of water? a)0.118 mol b)8.44 mol c)2736 mol d)6.02 x mol