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Molar Relationships

Pair = 2

Dozen = 12Names associated with an amountCan you think of any more?????

The mole (mol) is the amount of a substance that contains as many elementary entities as there are atoms in exactly 12.00 grams of 12C

1 mol = NA = 6.0221367 x 1023Avogadros number (NA) The Mole..

What is the mass of one mole of:CSCuFeHg3.2Molar MassThe Mass of 1 mole (in grams)Equal to the numerical value of the average atomic mass (get from periodic table) 1 mole of C atoms= 1 mole of Cu atoms =1 mole of S atoms = 1mole of Hg atoms = 1 mole of Fe atoms =Learning Check!Find the molar mass (usually we round to the tenths place)1 mole of Br atoms1 mole of Sn atoms=79.9 g/mole= 118.7 g/moleMolecular mass (or molecular weight) is the sum ofthe atomic masses (in amu) in a molecule.

SO21S32.07 amu2O+ 2 x 16.00 amu SO264.07 amuFor any molecule molecular mass (amu) = molar mass (grams)1 molecule SO2 = 64.07 amu1 mole SO2 = 64.07 g SO2 3.3Lets try some more..Molar Mass of Molecules and CompoundsMass in grams of 1 mole equal numerically to the sum of the atomic masses1 mole of CaCl2 = 111.1 g/mol 1 mole Ca x 40.1 g/mol + 2 moles Cl x 35.5 g/mol = 111.1 g/mol CaCl2Practice with this one: 1 mole of N2O4 = Learning Check!Molar Mass of K2O = ? Grams/mole

B. Molar Mass of antacid Al(OH)3 = ? Grams/mole

Learning CheckProzac, C17H18F3NO, is a widely used antidepressant that inhibits the uptake of serotonin by the brain. Find its molar mass.

So, if one mole = the formula mass how do we calculate.The mass of 05 mol of Calcium Carbonate

The mass of 2.25 mol of Sodium ChlorideHow many moles are there in? 100 g of Magnesium Hydroxide ?

64 g of Oxygen ?Converting to # of atoms or moleculesHow many atoms are in 3.00 moles of Iron?

How many atoms are in 0.25 moles of Water? Molar MassThe molar mass of a compound is found by adding Together the molar masses of all of its elements, takingInto account the number of moles of each element present.

Homework: pg 157 # 5-11Factor-Label Method (also called dimensional analysis)Use fractions that include numbers and units to convert from one item to another. All fractions must have a valued of 1

Example problem: How many seconds are there in one year? Types of Mole Conversion Problems:Grams to Moles --- Moles to GramsExample Problem:

How many Moles are in 58 g of NaHCO3?

How many grams are in 3.75 Moles of Water? Moles Particles (atoms,ions,molecules)How many atoms are in .75 moles of Oxygen Gas?

How many moles are in 2.709 x 1025 molecules of Calcium Hydroxide?

How many hydroxide ions are there in 4.5 Moles of Calcium Hydroxide?

Percent Composition Percent Composition the percentage by mass of each element in a compound Percent =_______PartWholex 100%SoPercent compositionof a compound or =molecule Mass of element in 1 mol____________________Mass of 1 molx 100%Percent Composition

Example: What is the percent composition of Potassium Permanganate (KMnO4)?Molar Mass of KMnO4K = 1(39.1) = 39.1Mn = 1(54.9) = 54.9O = 4(16.0) = 64.0MM = 158 g

Percent CompositionExample: What is the percent composition of Potassium Permanganate (KMnO4)?= 158 g% K Molar Mass of KMnO439.1 g K158 gx 100 =24.7 %% Mn54.9 g Mn158 gx 100 =34.8 %% O64.0 g O158 gx 100 = 40.5 %K = 1(39.10) = 39.1Mn = 1(54.94) = 54.9O = 4(16.00) = 64.0MM = 158Percent CompositionDetermine the percentage composition of sodium carbonate (Na2CO3)? Molar MassPercent Composition% Na =46.0 g106 gx 100% =43.4 %% C =12.0 g106 gx 100% =11.3 %% O =48.0 g106 gx 100% =45.3 %Na = 2(23.00) = 46.0C = 1(12.01) = 12.0O = 3(16.00) = 48.0 MM= 106 gHydratesHydrated salt salt that has water molecules trapped within the crystal latticeExamples: CuSO45H2O , CuCl22H2OAnhydrous salt salt without water moleculesExamples: CuCl2Can calculate the percentage of water in a hydrated salt.Hydrated Compounds: Chemicals that usually have water associated with them.How they are written:

BaCl2. 2H2O Barium Chloride dihydrate

CuSO4.5H2O Copper Sulfate pentahydrate

NaCO3.10H2O-__________________Percent CompositionIf 145 grams of copper (II) sulfate pentahydrate is completely dehydrated, how many grams of anhydrous copper sulfate will remain?

CuSO4 . 5 H2O1. Molar MassCu = 1 x 63.55 = 63.55 g S = 1 x 32.06 = 32.06 g O = 4 x 16.00 = 64.00 g MM = 159.61 gH = 2 x 1.01 = 2.02 gO = 1 x 16.00 = 16.00 g MM = 18.02 gMass of 5 moles of H2O =5 x 18.02 g = 90.1 gTotal Molar mass = 159.6 g + 90.1 g = 249.7 g2. % CuSO4159.6 g249.7 gX 100 =63.92 %3. Grams anhydrous CuSO40.6392 x 145 = 92.7 g Calculate the Molar Mass of Hydrates--ZnSO4.7H2O

Na2CO3.10H2OFormulasEmpirical Formula formula of a compound that expresses lowest whole number ratio of atoms.

Molecular Formula actual formula of a compound showing the number of atoms present Percent composition allow you to calculate the simplest ratio among the atoms found in compound.Examples:C4H10- molecularC2H5- empiricalC6H12O6- molecularCH2O- empiricalDetermining Empirical FormulaPERCENTGrams in 100g sampleMolesMole RatioEmpirical FormulaC40 %40 gH6.71%6.71 gO53.3%53.3 gTry this one: An oxide of aluminum is formed by the reaction of 4.151 g of aluminum with 3.692g of oxygen. Calculate the empirical formula.

ELEmentsPERCENTGrams in 100g sampleMolesMole RatioEmpirical FormulaA 4.550 g sample of cobalt reacts with 5.475 g chlorine to form a binary compound. Determine the empirical formula for this compound. ELEmentsPERCENTGrams in 100g sampleMolesMole RatioEmpirical Formula