Lecture 35 Reactions 2 Read HW BLB 3 6 3 7 BLB 3 57 64 73 79 Sup Rxns 1 11 Know oxidation reduction reactions stoichiometry calculations limiting reagents theoretical yield vs actual yield NO SCORE on Exam 3 talk with Mike in 210 Whitmore Check out the grad u lator on the Chem110 website Review chemical nomenclature e g BST 5 Lecture 8 memorize those strong acids bases BLB Table 4 2 Bonus deadline for BST 10 Net ionic equations Thurs April 16 FINAL SKILL CHECK TEST DEADLINE MONDAY APRIL 27 Missed Exam 1 2 or 3 due to illness Make up Exam Monday April 20 6 30 105 Wartik Covers material from Exams 1 3 multiple choice You must sign up by downloading completing the request form giving it to me deadline to sign up is April 15 info under Exam Schedule on Chem110 website Late drop deadline TODAY 11 59 pm via elion Need help Get help TAs in CRC 211 Whitmore and SI hours on Chem 110 website my office hours Mon 12 30 2 Tues 10 30 12 in 324 Chem Bldg or 326 Chem Sheets Page 1 Lecture 35 Metal displacement reactions or using the activity series of metals activity series BLB Table 4 5 shows relative ease of oxidation metal on list can be oxidized by metal salts or acids below it Cu s 2 Ag aq Cu2 aq 2 Ag s metals above H2 in series e g Mg Zn Fe will react with acid e g HCl to form H2 Zn s 2 HCl aq ZnCl2 aq H2 g metals toward bottom are unreactive e g Ag Pt Au that is the elemental form is most stable isn t it great that jewelry is made from these metals rather than say K Sheets Page 2 Lecture 35 Examples Will the metal element displace the atom from its compound in a reaction Na s H2O l Au s H2O g Zn s AgNO3 aq Sheets Page 3 Lecture 35 Example Zn s CuSO4 aq ZnSO4 aq Cu s LEO goes GER What is oxidized What is reduced ionic equation net ionic equation Sheets Page 4 Lecture 35 Types of reactions Table 3 1 Combustion reactions organic molecule O2 g CO2 g H2O g Combination reactions A B C e g N2 g 3 H2 g 2 NH3 g Decomposition reactions C A B e g C12H22O11 s 12 C s 11 H2O g Sheets Page 5 Lecture 35 To solve problems in chemistry write the balanced chemical reaction or process make connections between experimentally measured properties and the balanced equation In other words Given information such as mass volume pressure and temperature how can one determine quantities of moles molecules Recognize 1 what you know already what you are being asked for and 2 what connections will take you from knowns to unknowns Sheets Page 6 Lecture 35 Using balanced chemical equations quantitiatively use molar mass to convert moles grams use balanced equation to convert moles reactant moles product a balanced equation tells us the fewest number of molecules of each reactant it will take for the reaction to go to completion i e NO reactants left and the fewest number molecules of products that will then be formed 2 H2 O2 2 H2O molecules mol Sheets Page 7 Lecture 35 Example A How many g CO2 will be produced if we completely combust 12 00 g C6H12O6 B What is the mass of O2 consumed in this reaction C How many g H2O are produced C6H12O6 MW O2 180 g mol 32 g mol 12 00 g CO2 H2O 44 g mol 18 g mol Does conservation of mass hold That is mass of reactants mass of products Sheets Page 8 Lecture 35 Example 6 52 g of a compound containing C H and O is completely combusted to yield 9 56 g CO2 and 3 91 g H2O What is the empirical formula of the compound CxHyOz MW O2 32 g mol 6 52 g CO2 44 g mol 9 56 g emp formula Sheets Page 9 Lecture 35 H2O 18 g mol 3 91 g Before next class Read HW BLB 3 6 3 7 BLB 3 57 64 73 79 Sup Rxns 1 11 Know stoichiometry calculations limiting reagents theoretical yield vs actual yield Answers p 8 a 17 6 g CO2 b 12 8 g O2 c 7 2 g H2O p 9 CH2O Sheets Page 10 Lecture 35
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