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THE MOLE
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The Mole an amount of substance. Pull A really really really really BIG amount. In the words of Bill Nye, it's a "really hugely big" amount. Pull Intro to Mole Video
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Intro to the Mole Candy Activity Part 1 - Particles
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What is a mole? standard counting unit in chemistry (abbreviated “mol”) Relates # particles, mass, and volume of gases
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YOUR NEW BEST FRIEND - THE MOLE CIRCLE!!!
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PARTICLE PLACE Relates the mole to the number of particles CONVERSION FACTOR: 1 MOLE = 6.02 x 1023 Particles
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MOLES AND PARTICLES 6.02 X 1023 is also known as Avogadro’s Number Named after Italian chemist Amadeo Avogadro who determined that at the same temp and pressure, all gasses contained the same number of particles
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Examples of Particles (Amount): Atoms Na, K, Fe, Ne, Cl, Ag, U, Au, Po, I Particles of Elements Molecules CH4, C12H22O11, H2O, SO2, NO Particles of Covalent Cmpds Ions Li+, Ni2+, S2-, N3- PO43-, OH-, NH4+ Charged Particles Formula Units NaCl, CaSO4, Fe(OH)3, AgNO3 Particles of Ionic Compounds
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What is a formula unit? Molecular Compound CO2 Formula Unit NaCl Na+Cl-Na+Cl-Na+Cl- Cl-Na+Cl-Na+Cl-Na+ Na+Cl-Na+Cl-Na+Cl- smallest whole # ratio of ions in the cmpd. Molecules
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How many molecules are in 1 mole of molecules? Pull 6.02 x 1023 molecules
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How many formula units are in 1 mole of formula units? Pull 6.02 x 1023 formula units
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How many atoms are in 1 mole of atoms? Pull 6.02 x 1023 atoms
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How many ions are in 1 mole of ions? Pull 6.02 x 1023 ions
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1 new conversion factor YOU need to know. 1 mole = 6.02 x 1023 particles Mole Circle!!!! Particle Place
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SO....back to Dim Analysis Every problem must include for given, conversion factors and answer: Example: 6.02 x 1023 atoms Fe NumberSubstance Unit Use units - they must cancel Answer in correct significant figures
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Solving Mole Problems 1. Identify and label Given and Unknown. 2. Write down given x __________. 3. Put units of given on bottom of first conversion factor. 4. Use mole circle to figure out where you are starting, where you are going, how many steps and conversion factors to get you there. 5. Set up using dimensional analysis - number, unit, substance for each entry. Make sure units cancel along the way. 6. Multiply all items in numerator. Divide by numbers in denominator. 7. Answer - sig figs, units.
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2.05 x 1024 atoms SO....back to Dim Analysis How many atoms are in 3.4 mol of barium atoms? = 3.4 mol 6.02 x 1023 atoms 1 mol 2.05 x 1024 atoms
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And... How many mols of iron are in 5.6 x 1022 iron atoms? 0.93 mol Fe = 5.6 x 1022 atoms 1 mol 6.02 x 1023 atoms 0.093 mol
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3.97 x 1024 O atoms How many oxygen atoms are in 2.2 mol of BaCO3? = 2.2 mol BaCO3 6.02 x 1023 f.u. BaCO3 1 mol BaCO3 3-O atoms 1 f.u. BaCO3
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How many carbon atoms are in a mixture of 2.0 mol of CO2 and 3.5 mol of C6H12O6? = = 2.0 mol CO2 1 mol CO2 6.02 x 1023 CO2 molecules 1 CO2 molecule 1 C atom 3.5 mol C6H12O6 6.02 x 1023 C6H12O6 molecules 1 mol C6H12O6 1 C6H12O6 molecule 6 C atoms 1.2 x 1024 C atoms 1.26 x 1025 C atoms 1.2 x 1024 C atoms 1.26 x 1025 C atoms + 1.38 x 1025 C atoms
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Intro to the Mole Candy Activity Part 2 - Mass
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MASS AVE. Do you know how to measure out 1 mole of sugar or salt or water? The mole is a counting unit, so we would have to count out 6.02 x 1023 particles of each substance. (NO THANKS!) There are 2 ways to measure out a number of moles of a substance: Measure it in GRAMS ( a mass) If a GAS, measure it in LITERS ( a volume)
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MASS AVE. Relates the mole to the mass of one mole of substance CONVERSION FACTOR: 1 MOLE = Molar Mass of Substance Molar Mass/Atomic Mass/Gram Formula Mass/Molecular Weight
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TAKE OUT YOUR PERIODIC TABLE :)
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Molar Mass Pull AKA: Gram Formula Mass (GFM) Molecular Formula Mass (MFM) Formula Mass (FM)
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Pull 1 mol of any atom has a mass equal to it's atomic mass. Molar mass Pull The mass of 1 mole of substance.
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Carbon 12.011 Mg 24.03 Au196.97 1 mol of Carbon = 12.011 g 1 mol Mg = 24.03 g 1 Mol Au = 196.97 g Pull my Finger AtomAtomic Mass
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Hey that's a NEW conversion factor! 1 mol = molar mass of substance
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Molar Mass of a compound Pull Simply find the molar mass of each atom and add them together.
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What is the molar mass of NaCl? 1 mole of NaCl has a mass of 58.5 g Pull Na = 23 g + Cl = 35.5 g 58.5 g
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Pull 1 mol Ca = 40g x 1 = 40g 1mol O = 16g x 2 = 32g 1mol H = 1g x 2 = 2g 74g + Pull 1 mol K = 39.1 g x 2 = 78.2 g 1 mol S = 32 g x 1 = 32 g 1 mol O = 16 g x 4 = 64 g 174.2 g + What is the molar mass of K2SO4? What is the molar mass of Ca(OH)2?
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Mole to Mass and Mass to Mole Problems (same process as mole to particles, particles to mole!)
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How many grams of Al are in 3.00 moles of Al? Answer = 80.94 = 80.9 g Al
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What is the mass in grams of 2.7 mol of O2? Answer = 86.4 = 86 g O2
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Determine the number of moles in 5.00 g of H2O. Answer = 0.277469 = 0.277 mol of H2O
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Multi-Step Problems - Use the Mole Circle! Everything MUST go through the Mole!!!
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Calculate the number of grams of Na present in 3.00 x 1018 atoms of Na: = 0.0001146 g or 1.146 x 10-4 g of Na
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Calculate the number of atoms of Na in 160.00 grams of Na: = 4.189 x 1024 atoms of Na
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Penicillin, the first of a now large number of antibiotics, has the formula C14H20N2SO4. Calculate the mass of 2.0 x 1010 molecules of penicillin.
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Molar mass C14H20N2SO4 = 312.4 grams = 1.0 x 10-11 grams of penicillin 2.0 x 1010 molecules of penicillin
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2.0 x 1010 molecules Molar mass C14H20N2SO4 = 312.4 grams 6.022 x 1023 molecules 1 mol 312.4 grams = 1.04 x 10-11 grams of penicillin
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(0.5 mg) (3) = 1.5 mg 1.5 mg molar mass caffeine = 194.2 grams 1000 mg 1 g 194.2 g 1 mol 6.022 x 1023 molecules = 4.65 x 1018 molecules of caffeine
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How many atoms of carbon would be in 53.5 grams of isopentyl acetate (C7H14O2) ?
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Mass of the Part Mass of the Whole x 100 = % comp Percent Composition % by mass of elements in a compound. To solve: Assume 1 mole of compound. Then you can use..... Pull Mass of Element Pull Molar Mass of Compound
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Find the % composition of water. 1- Determine the formula of the compound and list its elements. Divide the molar mass of each element by the molar mass of the entire cmpd. 2g H 18g H2O = 0.11g 3- 0.11g x 100 = 11% H 0.89g x 100 = 89% O
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Find the % composition when 8.20g of Mg combines with 5.40g of O. 8.20g Mg 5.40g O 13.60g MgO + 8.20g Mg 13.60g MgO =x 100 60.3% Mg 5.40g O 13.60g MgO x100 = 39.7% O
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Pull Lowest whole number ratio of elements in a compound. Empirical Formulas
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Examples of Empirical Formulas H2O H3PO4 CH H2O2 C6H12O6 Not necessarily the "actual" formula!
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Pull A formula that specifies the actual number of atoms of each element in one molecule of a substance. Molecular Formulas
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Cmpd. Empirical Formula Molecular Formula glucose CH2O C2H4O2 glucose C2H4O2 CH2O formaldehyde CH2O acetic acid CH2O C2H4O2 glucoseCH2O C6H12O6
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How to Calculate Empirical Formulas Pull Step 1. Find the number of moles of each element. (If % is given, assume 100g of compound; % = grams) Pull Step 2. Divide number of moles of each element by smallest number of moles. (finding ratio of # moles of each) Pull Step 3. Find the lowest whole number ratio. Write formula with subscripts reflecting ratio.
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An alkaline battery contains 63.0 % Mn and 37.0% oxygen by mass. Find the empirical formula of the cmpd.
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An unknown cmpd was analyzed and found to contain 26.56% K, 35.41% Cr, 38.03% O. Find the empirical formula for the compound.
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Calculating Molecular Formulas Molar mass of unknown molecular formula will be given to you!!! Pull Step 1. Find the Empirical Formula. Pull Step 2. Determine the molar mass of empirical formula Pull Step 3. D etermine ratio of molecular mass to empirical formula mass. ratio = molecular molar mass (given) calc. molar mass of emp. form Pull Step 4. Write molecular formula by multiplying subscripts of empirical formula by ratio in step 3.
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Calculating Molecular Formulas 1. The empirical formula of a compound is NO2. Its molecular mass is 92 g/mol. What is its molecular formula? 2. A compound is found to be 40.0% carbon, 6.7% hydrogen and 53.5% oxygen. Its molecular mass is 60.0 g/mol. What is its molecular formula?
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Calculating Molecular Formulas: Step 1: Find the empirical formula mass. Step 2: Divide molar mass by emp. formula mass. Step 3: multiply answer from step 2 by the empirical formula (how? multiply subscripts!) What is the molecular formula if it's molar mass is 60 g/mol and it's emp. formula is CH4N?
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1 mol = 6.02 x 1023 particles 1 mol = molar mass If you can convert mass to mols you can then convert mols to particles. If you can convert particles to mols you can convert mols to mass. mass is expressed in grams Particles are atoms, ions, molecules and formula units.
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Attachments Mole Circle Link.docx
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