英文实验报告

Qualitativedeterminationoftheelementsoforganiccompounds

Part1Thepurposes

1Learntheprinciplesoftheanalysisofelements.

1Mastertheinspectionmethodofcommonelements.

Part2Theprinciples

2.1Theinspectionofhydrogenandcarbon

Ba(OH)2+CO2→BaCO3↓+H2O

Observethetesttubewallwithorwithoutwaterdrop.

2.2Theinspectionofsulfurandnitrogen

3NaCNS+FeCl3→Fe(CNS)3(sanguineous)+3NaCl

2.2.1Theinspectionofnitrogen

FeSO4+6NaCN→Na4[Fe(CN)6]+Na2SO4

3Na4[Fe(CN)6]+4FeCl3→Fe4[Fe(CN)6]3↓(blue)+12NaCl

2.2.2Theinspectionofsulfur

2.2.2.1Na2S+2HAc→H2S↑+2NaAc

H2S+Pb(Ac)2→PbS↓+2HAc

2.2.2.2Na2S+Na2Fe(CN)5NO→Na4Fe(CN)(NOS)(claret-colored)

2.3Theinspectionofhalogen

NaX+AgNO3→AgX↓+NaNO3

2I-+Cl2→2Cl-+I2(ApurplecolorappearsinCCl4layer.)

I2+5Cl2+6H2O→2IO3-+12H++10Cl-(ThepurplecolorinCCl4layerfades.)

2Br-+Cl2→2Cl-+Br2(AbrowncolorappearsinCCl4layer.)

Part3Thematerialsandapparatus

sucrose

solution;copper(II)oxide;bariumhydroxide;sodium;10%aceticacid;

lead

acetate

testpaper;sodiumnitroprusside;10%

sodium

hydroxide

;iron(II)sulfate;iron(III)chloride;10%sulfuricacid;dilutedhydrochloricacid;5%

silver

nitrate

;dilutedsulfuricacid;

carbon

tetrachloride

;Saturatedchlorinewater;Saturatedchlorinewater;0.1%ammoniumhydroxide;concentratedsulfuricacid;0.5%sodiumpersulfate.

Part4Theprocedures,phenomenaandconclusions

Procedures

Phenomena

Conclusions

Equations

Mixspecimenanddrycopper(II)oxide.——heating——Thegasisbubbledintobariumhydroxidesolution.

Thereiswaterdropontesttubewall

Thereishydrogeninthecompound

Bariumhydroxidesolutioniscloudy.

Thereiscarboninthecompound.

Ba(OH)2+CO2→BaCO3↓+H2O

Heatasmallamountofsamplewithasmallpieceofsodium.——Putthenincoldwater.——Breakthetesttube.——Filterthesolution.(Callthesolutionsodiumsolution.)

Procedure

Phenomenon

Conclusions

Equation

Put2mLofsodiumsolutionintothetesttube.——Addafew10%aceticacid——Boil——Putapieceof

lead

acetate

testpaperintothetesttube.

Blackpointsappearonthetestpaper.

Thereissulfurinthecompound.

Na2S+2HAc→H2S↑+2NaAc

H2S+Pb(Ac)2→PbS↓+2HAc

Putasmallgrainofsodiumnitroprussideintoseveraldropsofwater.——Pourthesolutioninto1mLsodiumsolution.

Thesolutionisclaret-colored.

Thereissulfurinthecompound

Na2S+Na2Fe(CN)5NO→Na4Fe(CN)(NOS)

Addseveraldropsof10%

sodium

hydroxide

into2mLofthesodiumsolution.——Addasmallgrainofiron(II)sulfate.——Boilfor1minute.——Coolit.——Addtwodropsof5%FeCl3and10%H2SO4.

Thereisbluesediment.

Thereisnitrogeninthecompound.

FeSO4+6NaCN→Na4[Fe(CN)6]+Na2SO4

3Na4[Fe(CN)6]+4FeCl3→Fe4[Fe(CN)6]3↓+12NaCl

Addseveraldropsofdilutedhydrochloricacidandadropof5%FeCl3into1mLsodiumsolution.

Thesolutionissanguineous

Therearenitrogenandsulfurincompounds

3NaCNS+FeCl3→Fe(CNS)3(sanguineous)+3NaCl

Put1mLofsodiumsolutionintoatesttube.——Addafew5%

nitric

acid

.——Boil.——Coolit.——Addseveraldropsof5%AgNO3.

Thereissediment.

Thereishalogeninthecompound.

NaX+AgNO3→AgX↓+NaNO3

Addafewdilutedsulfuricacidinto2mLof

filtrate

.——Boil——Coolit.——Add1mLCCl4andadropofnewchlorinewater.

Thepurplecolorfades.Brownsedimentappears.

Thereisbromineinthecompound.

I2+5Cl2+6H2O→2IO3-+12H++10Cl-

2Br-+Cl2→2Cl-+Br2

Addafewdiluted

nitric

acid

into10mLoffiltrate.——Boil——Addenough

silver

nitrate

.——Filter——Thesedimentiswashedby30mLofwater.——Boilitand20mLof0.1%

ammonium

hydroxide

for2minutes.——Filter——Addafew

nitric

acid

and

silver

nitrate

intothefiltrate.

Thereiswhitesediment.

Thereischlorineinthecompound.

NaCl+AgNO3→AgCl↓+NaNO3

Part5Theresult

Accordingtothephenomena,wecanlearnthecompoundcontainshydrogen,carbon,sulfur,nitrogen,chlorineandbromine.

Part6Discussion

6.1Q:What'sthemeaningofthequalitativedeterminationoftheelements?Whyusethesodium-fusionmethodtoinspectnitrogenandsulfur?

A:Itcanidentifyaparticularelementoforganiccompoundsthatdeterminequalitativelytheelementsoforganiccompounds.Itcanhelpustoselectthewaysandmethodstoidentifyelementsofunknownspecimendeeply,andthequalitativedeterminationoftheelementsisthepreparationofquantitativeanalysis.Inspectionofnitrogenandsulfurwithsodium(orpotassium)-fusionmethodmakesthenitrogenandsulfuroforganiccompoundsintosolubleinorganiccompounds,thenseparateandinspectCN-,S2-andsoon.

6.2Q:Howtodealwiththetinysodiumthatstickstothefilterpaper,whenwecutthesodiumonthefilterpaper?

A:Thetinysodiumthatstickstothefilterpapercanbedealtwithbyethylalcohol,youmustnotcastitintothetank,disposalbottleanddustbin.

6.3Q:Whatgasemissionislikelytobewhenweidentifythehalogen,if

specimen

containingsulfurandnitrogen,while,dealwiththembynitricacidandboiling?Howtosolvecorrectly?

A:Itisthegasofhydrogensulfideandformo