初中化学经典计算题The classical calculation problems of junior high school chemistry文档格式.docx

初中化学经典计算题The classical calculation problems of junior high school chemistry文档格式.docx

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（2）adayforadultsisabout0.15mg,assumingthatthesearemainlyfromiodizedsaltintakeofiodizedsalt,iodineiniodizedsaltif20mg1000gisrequired,adultdailyconsumptionofiodizedsalt____________.g

2.existingimpuritiesinSolidBariumChloridesamples（waterinsolubleimpurities）,take12.5gsamplesintothebeaker,thenadd39.6gofwatertomakeitfullydissolved,staticfilteredimpurities,10gfiltrate,silvernitratesolutionaddenough,aftercompletereactiontoprecipitate2.87g.（thecalculationisaccurateto0.1%）

（1）themassfractionofsoluteinfiltrate;

（2）themassfractionofbariumchlorideinthesample.

3inJilinProvince,someextra-curricularinterestgroupsonanumberofsamples（ironcontainingimpuritiesimpurities,insolubleinwater,noreactionwithdilutesulfuricacid）wereanalyzed,a,BandCthreestudentstestwerecarriedoutincludingdilutesulfuricacidandironsamplesonlyonestudentforexactlythereactiontheexperimentaldataarelistedinthefollowingtable:

ABC

Beaker+dilutesulphuricacid200g,150g,150g

Theaddedironsample9g,9g,14g

Afterfullreaction,beaker+residue208.7g,158.7g,163.7g

Pleaseanalyzethedatacarefullyandanswerthefollowingquestions:

（1）thedilutesulfuricacidwhichtheclassmatetookisjustacompletereactiontotheironsample;

（2）calculatethemassfractionofironinthesample;

（3）calculateexactlythemassfractionofsoluteinthesolutionobtainedaftercompletereaction.（thequalityofthebeakeris25.4g;

thecalculationisaccurateto1%）

4.Burn4Gsulfurpowderinagivenmassofoxygen.Theexperimentaldataareshowninthefollowingtable.Pleaseanswerthefollowingquestions:

Thefirsttimeortwoorthreetimes

O2mass（g）346

SO2mass（g）6

（1）inthefirstexperiment,qualityandgenerationinresponsetothequalityoftheSandO2SO2ratiois:

_________.

（2）pleasecalculatehowmuchsulfurdioxideisproducedbythesecondexperiment

（3）filloutthethirdexperimentintheformtoproducethequalityofsulfurdioxide.

Heilongjiangprovince5,10gimpuremagnesiumchloridesamples（impuritiesinsolubleinwater）,

50gthewaterisfullystirred,andthemagnesiumchlorideinthesampleisdissolvedandfiltered（filtratelossisnotnegligible）,andthefiltrateisreactedwith63.3gsodiumhydroxidesolutiontoproduce5.8Gwhiteprecipitate.

Beg:

（...）QualityofMagnesiumOxideinsample.

（2）themassfractionofsoluteinthesolutionobtainedbythereaction.

6,"

osteoporosis"

iscausedbythebody'

scalciumdeficiency,canbetakencalciumsupplementstotreat.Calciumlactate（CaC6H10O6?

5H2O）isacommoncalciumsupplement,thesaleofCalciumLaclateTabletstabletscontainingcalciumlactate200mg.anadultcalciumdeficiencypatientstake20tabletsdailyCalciumLaclateTabletsagentcanachievetheobjectiveofcalcium.Calculation:

（calculationresultsretaininteger）

（1）themassratioofeachelementincalciumlactate.

（2）theadultpatientswithcalciumdeficiencyshouldswitchtomilk（calcium0.104gineach100mgmilk）tosupplementcalcium.Howmanymlofmilkshouldbeconsumedatleasteveryday?

.

JiangsuProvince,7ironandsteelalloyofiron,carboncontentinpigironin2.0%~4.3%,steelcarboncontentin0.03%~2%.Amassofironalloy10.0gintoaconicalflasktotheconicalflaskadd100gofdiluteH2SO4,justtomaketheironalloyironreaction（carboninsolubleindilutesulfuricacid;

otherelementsinironalloyisverylowandnegligible）,measuredtogenerateH2volume4.00L（H2densityintheconditionof0.0880g/L）.Accordingtothecalculation,answer:

（calculatetheresulttoretainthreedigits.）

（...）Istheironalloypigironorsteel?

（2）thesolutemassfractionofthesolutionobtainedafterthereaction.

NingboCity,8to3.1gramsofsodiumoxideisaddedtothequalityofmwater,aftercompletereaction,getthesolutemassfractionis16%ofthesolution,adding50gramsofhydrochloricacidinthesolution,bothexactlythereaction.（sodiumandwaterreactionchemicalequation:

Na2O+H2O==2NaOH）.O:

（1）thevalueofM

（2）themassfractionofsoluteinhydrochloricacidadded.

（3）ifthesodiumhydroxidesolutionafterthereactionbecomes20?

Csaturatedsolution,atleasttoevaporatehowmanygramsofwater?

（20?

C,thesodiumsolubilityis36grams）

Anhuiprovince9,thefollowingistheprovinceofsomeofthecalciumplussaltpackaginglabelsonthe