EC PS3 - Problem set 3 PDF

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Problem set 3...

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Environmental,Chemistry, , , , , , Spring,2018, Prof.,Curran, ! Problem(Set(#3.((Due(at(the(start(of(class(on(Thursday,(February(15,(2018.( ! Complete!all!answers!legibly!on!a!separate!sheet(s)!of!paper.!!! ! 1.!!In!photochemical!smog!one!finds!the!chemical!peroxyacetic!nitric!anhydride!(drawn! below).!!This!chemical!is!a!major!source!of!eye!irritation!in!areas!with!photochemical! smog.! ! H 3C

O C

O

O

N O

O

! ! A.!!Peroxyacetic!nitric!anhydride!is!a!neutral!molecule.!!Redraw!this!molecule!as!a!Lewis! structure.!!Show!all!lone!pairs!and!non-zero!formal!charges.! ! B.!!Peroxyacetic!nitric!anhydride!is!formed!by!a!reaction!with!chemical!X!with! atmospheric!NO2.!!Identify!X!and!show!using!Lewis!structures!and!electron!pushing! arrows!how!peroxyacetic!nitric!anhydride!is!made.! ! C.!!Chemical!X!(from!part!B)!is!formed!by!a!reaction!between!chemical!Y!and!O2.!!Identify! Y!and!show!using!Lewis!structures!and!electron!pushing!arrows!how!chemical!X!is! formed.! ! d.!!Chemical!Y!(from!part!C)!and!water!are!formed!by!a!reaction!of!hydroxyl!radical!with! a!chemical!Z.!!Identify!Z!and!show!using!Lewis!structures!and!electron!pushing!arrows! how!Y!is!formed.! ! ! ! 2.!!One!source!estimates!that!in!a!polluted!urban!environment!the!concentration!of! hydroxyl!radical!is!2.5!x!106!molecules/mL.!! ! A.!!Convert!this!concentration!to!ppm.! ! B.!!Convert!this!concentration!to!moles/L! ! C.!!What!is!the!partial!pressure!of!hydroxyl!radical!in!the!atmosphere?!!Express!your! answer!in!the!units!Pa.! ! D.!!What!volume!of!air!would!contain!one!mole!of!hydroxyl!radical?!

! ! 3.!!HCFCs!are!not!as!destructive!to!the!ozone!layer!in!the!stratosphere!because!they!do! not!make!it!into!the!stratosphere;!they!are!destroyed!in!the!troposphere.!!HCFC-22!is! used!in!air!conditioning.!!If!some!HCFC-22!is!released!into!the!troposphere,!it!will!react.!! Show!the!initial!reaction!of!HCFC-22!in!the!troposphere!using!Lewis!structures!and! electron!pushing!arrows.! ! 4.!!Hydroxyl!radical!can!be!produced!from!several!different!precursor!chemicals.!!One!of! these!reactions!is!the!following:! ! NO2!!!!+!!!!H2O!!!-------!!!!!NO!!!!+!!!2!!HO! ! Show!how!the!two!reactants!interact!(using!electron!pushing!arrows)!to!yield!the!two! products!here.! ! ! 5.!!The!concentration!of!the!organic!molecule!o-xylene!was!found!to!be!510!µg/m3!in! Taipei!City.!! ! A.!!Draw!the!Lewis!structure!of!o-xylene.! ! B.!!Convert!the!reported!concentration!of!o-xylene!to!mol/L.! ! C.!!Convert!the!reported!concentration!of!o-xylene!to!ppm.! ! D.!!O-xylene!will!be!decomposed!in!the!atmosphere.!!In!one!case,!it!gets!converted!to! the!molecule!shown!below.! ! O H

CH3

! ! Show!the!reactions!responsible!for!converting!o-xylene!to!this!compound.! ! E.!!O-xylene!will!be!decomposed!in!the!atmosphere.!!In!another!case,!it!gets!converted! to!the!molecule!shown!below:! ! H 3C

CH3

OH !

! Show!the!reactions!responsible!for!converting!o-xylene!to!this!compound.! ! ! 6.!!The!concentration!of!ground-level!ozone!can!be!determined!by!allowing!the!gas!to! react!with!an!aqueous!solution!of!KI!in!a!redox!reaction!that!produces!I2,!O2!and!KOH.! ! A.!!Write!out!the!balanced!equation!for!the!redox!reaction.! ! B.!!Determine!the!ozone!concentration,!in!ppb,!in!a!10.0!L!sample!of!outdoor!air!if!it! required!17.0!µg!of!KI!to!react!with!it.! ! ! 7.!!The!average!outdoor!concentration!of!CO!is!1000!µg/m3.!!! ! A.!!What!is!the!concentration!of!CO!expressed!on!the!ppm!scale?! ! B.!!What!is!the!concentration!of!CO!on!the!molecules/cm3!scale?! ! ! 8.!!One!of!the!ways!that!hydroxyl!radical!is!removed!from!the!atmosphere!is!by! reactions!with!other!radicals.! ! A.!!What!is!the!product!if!hydroxyl!radical!reacts!with!NO?!Write!out!a!balanced! equation!using!Lewis!structures., ! B.!What!is!the!product!if!hydroxyl!radical!reacts!with!NO2?!Write!out!a!balanced! equation!using!Lewis!structures.! !...