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CHEMISTRY - ZUMDAHL & DECOSTE 10ECH.3 - STOICHIOMETRY
CONCEPT:CALCULATING MOLAR MASSMolar Massis a physical property that represents the mass of a substance divided by the amount of that substance.The SI units for mass is kg and the amount of substance is moles, but molar mass is in __________.Molar mass is also referred to as ______________ weight, ______________ weight or ______________ mass.STEP 1:Count thenumberof each element within the given compound.If elements are within parentheses, just remember to distribute thesubscriptto each element.STEP 2:Find theatomic massesof each element from the Periodic Table.STEP 3:Multiply together thenumberof each element with theiratomic massesfrom the Periodic Table.STEP 4:Add up the totals after multiplication to determine the molar mass of the compound.Molar Mass FormulaMolar Mass =_______ N_______ S_______ H_______ O(NH4)2SO41HHydrogen1.0087NNitrogen14.018OOxygen16.0016SSulfur32.07___Nx14.01g/mol = _______ g/mol___Hx1.008g/mol = _______ g/mol___Sx32.07g/mol = _______ g/mol___Ox16.00g/mol = _______ g/molEXAMPLE:Calculate the molar mass of the compound (NH4)2SO4.CHEMISTRY - ZUMDAHL & DECOSTE 10ECH.3 - STOICHIOMETRYPage 2
CONCEPT:CALCULATING MOLAR MASSPRACTICE:Calculate the molecular weight of C3H5N3O3.PRACTICE:The reaction between nickel metal and hydrochloric acid is not a simple dissolution. The product formed isNiCl2·6 H2O (s), nickel (II) chloride hexahydrate, which has exactly 6 waters of hydration in the crystal lattice for everynickel ion. What is the molar mass of nickel (II) chloride hexahydrate, NiCl2·6 H2O (s)?PRACTICE:What is the molar mass of diazepam also known as Valium if 0.05570 mol weighs 15.86 g?CHEMISTRY - ZUMDAHL & DECOSTE 10ECH.3 - STOICHIOMETRYPage 3
CONCEPT:MOLE CONCEPTThe MoleThe mass of substance “containing the same number of units as atoms in 12.00 g of Carbon-12” and connects together:Atom: A single element with no charge.Ion: A single element with ______ or ______ charge.Molecule: A compound with 2 or more ____________ together.Formula Unit: General term for a compound composed of a(n) __________ and __________.Converting between Moles and ParticlesAvogadro’s Number: One mole of a substance is equal to__________________particles.Particles:A general term that is used for ions, atoms, molecules or formula units.1 mole of chlorine, Cl2, equals 6.022 x 1023molecules Cl2.______________EXAMPLE:Which of the following compounds would not be associated with the term “formula unit”?a) Na2CO3b) CH3COONac) BF3d) MnCl4EXAMPLE:How many moles of chlorine gas are there in 8.33 x 1037molecules?molCHEMISTRY - ZUMDAHL & DECOSTE 10ECH.3 - STOICHIOMETRY
Converting between Mass and MolesOne mole of a substance is equal to the molar mass of that substance.1 mole of chlorine, Cl2, weighs 70.90 grams.______________EXAMPLE:How many grams of chlorine gas are there in 2.34 moles?
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CONCEPT:MOLE CONCEPTConverting between Mass and ParticlesAs we’ve stated earlier, the unit of mole serves as a bridge that connects together the other units.PRACTICE:If a sample of sodium chloride, NaCl, contains 73.1 kg, what is its number of formula units?

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Term
Spring
Professor
Wescott
Tags
Stoichiometry, Molecular formula

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