University:
Mississippi College
Course:
CHE 141 | General Chemistry I
Academic year:

2022
Views:

436

Pages:

4
Author:

Abby D.

Ch. 5 PT: 2 Gas Evolution/Redox/CombustionGasevolution Rxns: fat leastony.com be a solid or l)&occur when two aqueus solution are mixed together, andone (or of more) gases are produced.revidenceby bubdes in solnEx: NaHCO3C aq) - Sodium BicarbonateNaHCO3(aq).+H2OU) + Nacl (aq) + CO2(g)Oxidation-Reduction - RXNS: Caka Redox rxns)Be able to:1) Recognize a redoxrxn 2)Determine which reactant is oxidizedand which is reduced.3)identify reducing and OXI dizing agents4) Assign oxidation numbers to atoms.They are rxn's in which electron(s) are transferred from onereactant to the other,labelsConsider this rxn:Ignore and Professionals2Mg (s) + 02(g)2 Mgocs)e-currency of chemcharges on individual2+ 2-atoms :0 charge Ochargekey PT: awhat h appened ?All elementsRAmg 02+ lost e's LEOxidizedare neutral02 gained e-'s GEReducedOALEO the lion GER ]goes"The one that"The one that gainedlost electronselectrons was reduced"was oxidizedJ consider this rxn:2A1 + 3Ca3ca + + 2A12+changes: 3+ O2+OOATAI3+O GEReducedRA-1cao2+ LEOxidizedxidation Numbers (states): 2 t "charges" + 2 ox #"4 IS it a redox rxn?: transfer of electrons2H2 +O22 H2ON malecular (NM/NM/covalent noions/no charges)charges:=02-4-=0POVOF the HetyHatomOOridation #erPartial transferof aneOtherHHOxidation #ers: the "charge" an atom would have if the bonded e-swere ASSIGNED to whatever atom pulls them tighter.A13t-monoatomic2H2+O22H2O Co.neutral-nocharge up topoxttersO0+1 -2on idiv.atoms:fentralaH-ORALEOxidized00-2 GEReducedOAAssign oxtters on each individual atom:CrCr3+CCly+3+4-1isSO3+2-17NO3+6-2+5-2KNO22KNO2H2O2CIO26+9=+1+3or+1-1+5-2+1 +3 -2& few times⑉Ois nota242 eges-ooxidation # change no,ifit doesn'tQuestion: Is this a redox rxn? If so, Identify the RA, yesSn(s)+4HNO3(a1q) SnO2(s) + 4NO2 (g) + 2H2Ocg)OX#0 +1+5-2-2+4-2+1 -2RAISh 0 +4 LEOxidized+1+1OAIN+5-4 GEReduced0-2-2containsCBHCombustionRxn:typeofredoxinwhichonorganicis burned in the prescence of O2 producing,H1206C3H8 " hydro-CO2 and H2 (a lot of heat energy)always, O2CH3OHCu H10 / carbonsCH4CH4 + 202CO2 +2+20-4+10+4.2+1-2OXAmethore(natural gas)RAC-4+4 LEOxidizedH+1+1OMO2 GEReduced2 Write the Combustion rxn for CH3 OH.2CH3OH+3022CO2 +4H2OBalancing: C first then H thenComb rxn: C3H8C3Hg+5023CO2 + 4H2O7 Combustion AnalysisLabtechniqueusedtodeterminetheempiricalformulaofanorganic cmpd: (only hydrocarbons)emp. formulasvsNmolecular formulastells you the ratio oftells you the actual atoms inatums to each otherthe cmpd (Normal)CH2OC6HRO6HOH2O2C3HgC3HHtho2UponCombustion,hydrocarbonproduced01.60gCO2andimolmothl0.81919H2O.Determineitsemp.formula.H20C3H2O2 O2moi molCHAMICO2H2Ocollection collectionHyou0.036360,090921.60gCO2xmol CorImale=0.03636m0160103636 4 0,0363644.01gEO2IMGICO2C H2.5Hax20.819 gH20x/M01H202motH=0.09092C2Hs(18.016g+120)ImpiH2OmolH