Izinombolo ezibalulekile ekubaleni kwekhemistri

Izinombolo ezilinganisiwe nezinombolo eziqondile

Inani elilinganisiwe alinasiqiniseko ngoba wonke insimbi yokukala inomkhawulo. Lapho ufunda i-buret ehlukaniswe ngamanyathelo angu-0.1 mL, ubhala amamaki aqinisekile bese uqagela inombolo eyodwa eyengeziwe phakathi kwawo, ngakho ukufundwa okufana no-18.36 mL kunezinombolo ezibalulekile ezine: izinombolo ezintathu eziqinisekile nenye eqagelwayo. Ukubhala u-18.360 mL kuzoba njengokusho ukucophelela okungekho ku-buret.

Izinombolo eziqondile azinabungozi bokungaqiniseki kokulinganisa. Zivela ekubaleni (amashubhu okuhlola angu-12 emkhunjini), ezincazelweni (i-inch eyodwa ingu-2.54 cm ngqo, kanti u-1 L ungu-1000 mL ngqo), nasezinombolweni ezandulela nezingezansi kumafomula nasezibalweni zamakhemikhali. Zithathe njengezinombolo ezibalulekile ezingenamkhawulo, ngakho azilokothi zikhawulele ukucophelela komphumela obaliwe.

Ukubala izinombolo, kuhlanganise ne-zero ezibangela inkinga

Izinombolo ezingezona i-zero ziyabalulekile njalo. I-zero ibalulekile noma ayibalulekile kuye ngokuthi ibika ulwazi olulinganisiwe yini noma imaka kuphela indawo yephoyinti ledesimali. Imithetho engezansi ihlanganisa wonke amacala ozohlangana nawo ekhemistri evamile.

Ama-zero ahlala ngemuva enanini eliphelele elingenaphoyinti ledesimali yiwo kuphela icala elingaqondakali ngempela. Isisindo esibhalwe ngokuthi 1200 g singaziwa ngezinombolo ezibalulekile ezimbili, ezintathu noma ezine. Ukubhala kwesayensi kuyakususa ukungaqondakali: 1.2 × 10³ g inezimbili, 1.20 × 10³ g inezintathu, futhi 1.200 × 10³ g inezine.

• Ama-zero aphakathi kwezinombolo ezingezona i-zero ayabalulekile: 30.506 g inezinhlanu.
• Ama-zero angaphambili awabalulekile neze; amaka kuphela indawo yephoyinti ledesimali: 0.004070 m inezine (4, 0, 7, 0).
• Ama-zero ahlala ngemuva ngakwesokudla sephoyinti ledesimali ayabalulekile: 2.500 mL inezine.
• Ama-zero ahlala ngemuva enanini eliphelele elingenaphoyinti ledesimali awaqondakali; sebenzisa ukubhala kwesayensi ukuze uveze inhloso yakho.

Ukuhlanganisa nokukhipha: lingisa izindawo zamadesimali

Lapho amanani ehlanganiswa noma ekhishwa, ukungaqiniseki okubalulekile yilokho okuphelele endaweni yokugcina yedesimali, hhayi inani lezinombolo ezibalulekile. Yiyisa umphumela ube nezindawo zamadesimali ezifanayo nezesilinganiso esinezindawo zamadesimali ezimbalwa kunazo zonke.

Isibonelo esisebenzile 1. Uhlanganisa izingxenye ezintathu zento eqinile ezikalwe ezikalweni ezahlukene: 12.6 g, 0.237 g, no-105.42 g. Isibali sikhombisa u-118.257 g. Isisindo sokuqala siziwa kuphela endaweni yeshumi, ngakho isamba siziwa kuphela endaweni yeshumi: 118.3 g. Qaphela ukuthi impendulo inezinombolo ezibalulekile ezine nakuba enye ye-inputhi ibinezintathu kuphela; ekuhlanganiseni, ukubalwa kwezinombolo akuyona into ekhawulela umphumela.

Ukukhipha kungabhubhisa izinombolo ezibalulekile. Cabanga ngomkhumbi oqukethe uketshezi osindisa u-58.36 g esikalini sokuthulula phezulu, kanti ifilasiki engenalutho wawusindisa u-57.912 g esikalini sokuhlaziya. Umehluko ngu-0.448 g esibalini, kodwa isisindo sokuqala siziwa kuphela endaweni yekhulu, ngakho isisindo soketshezi singu-0.45 g. Kusala izinombolo ezibalulekile ezimbili kuma-inputhi ayenezine nezinhlanu. Lapho umehluko omncane phakathi kwezinombolo ezimbili ezinkulu ubalulekile, kala zombili esikalini esinokucophelela okukhulu.

Ukuphindaphinda nokwahlukanisa: bala izinombolo ezibalulekile

Ekuphindaphindeni nasekuhlukaniseni, ukungaqiniseki okuhlobene yikho okuqhubekayo. Yiyisa umphumela ube nezinombolo ezibalulekile ezifanayo nye-inputhi enezinombolo ezibalulekile ezimbalwa kunazo zonke.

Isibonelo esisebenzile 2. Ibhlokhi eyisikwele ilinganisa u-4.20 cm ngo-2.15 cm ngo-1.8 cm. Ivolumu ngu-4.20 cm × 2.15 cm × 1.8 cm = 16.254 cm³ esibalini. Ubude bunezinombolo ezibalulekile ezimbili kuphela, ngakho ivolumu ibikwa ngokuthi 16 cm³. Ukulinganisa ubude ngokucophelela okukhulu, njengo-1.80 cm ngekhaliphasi, kuyoba yiyona ndlela eyodwa yokuthethelela inombolo yesithathu.

Ama-logarithm alandela umthetho ohlobene ovela emsebenzini we-pH: inani lezindawo zamadesimali ku-logarithm lilingana nenani lezinombolo ezibalulekile ezinanini lokuqala. Ukugxila kwe-ayoni ye-hydrogen okungu-3.4 × 10⁻⁴ mol/L kunezinombolo ezibalulekile ezimbili, ngakho i-pH yakhona ibikwa ngezindawo ezimbili zamadesimali, 3.47.

Ukuyisa kanye, ekupheleni kokubala kwamasinyathelo amaningi

Ekubaleni okunamasinyathelo amaningana, gcina okungenani inombolo eyodwa noma ezimbili ezengeziwe (izinombolo zokulondoloza) kunani ngalinye eliphakathi bese uyisa impendulo yokugcina kuphela. Landelela ukuthi izinombolo ezibalulekile ezingaki ezigunyazwa isinyathelo ngasinye, kodwa ungalahli izinombolo kuze kube sekugcineni. Ukuyisa esinyathelweni ngasinye kwengeza iphutha elincane njalo, futhi lawo maphutha angashintsha inombolo yokugcina ebikiwe.

Isibonelo esisebenzile 3. Incibilikisa u-1.37 g we-sodium chloride emanzini bese uyihlanjulula ize ibe ngu-50.00 mL ngqo esitsheni sevolumu. Usebenzisa izisindo ze-athomu ezijwayelekile ze-IUPAC eziyiswe ezindaweni ezimbili zamadesimali (Na 22.99, Cl 35.45), isisindo se-molar se-NaCl singu-58.44 g/mol. Inani lingu-1.37 g ÷ 58.44 g/mol = 0.023443 mol, lingayiswanga. Ivolumu ingu-0.05000 L, ngakho ukugxila kungu-0.023443 mol ÷ 0.05000 L = 0.46886 mol/L, okuyiswa ku-0.469 mol/L ngoba isisindo sinezinombolo ezibalulekile ezintathu.

Ukube uyise inani ku-0.0234 mol kuqala, ubuzothola u-0.0234 mol ÷ 0.05000 L = 0.468 mol/L. Umehluko mncane, kodwa liphutha langempela elibangelwa izibalo hhayi izilinganiso, futhi ezilandwini ezinde lingakhula.

Ingabe uyisa izinombolo eziphakathi phezulu noma ezinombolweni ezilinganayo

Uma inombolo yokuqala oyilahlayo ingaphansi kuka-5, shiya inombolo egciniwe injalo; uma inkulu kuno-5, noma ingu-5 elandelwa yinoma iziphi izinombolo ezingezona i-zero, yisa phezulu. Ngakho u-0.064371 uyiswa ku-0.0644 kanti u-7.2849 uyiswa ku-7.28 ngezinombolo ezibalulekile ezintathu.

Icala eliphikiswayo kuphela yinombolo elahlwayo engu-5 ngqo engenalutho emva kwayo. I-OpenStax Chemistry 2e iyisa ukuze inombolo egciniwe ibe ngeyalinganayo (6.125 iba ngu-6.12, kanti 6.135 iba ngu-6.14), okugwema ukuthambekela okuncane phezulu ekuyiseni okuningi. Othisha abaningi bavele bayise u-5 phezulu. Hlola ukuthi isifundo sakho sisebenzisa muphi umgomo bese uwusebenzisa ngokungaguquki; uthinta leli cala elilodwa kuphela.

Amaphutha ezinombolo ezibalulekile okufanele uwabheke emsebenzini wakho

Amaphutha amaningi ezinombolo ezibalulekile avela ekuphutheni okumbalwa okuhlanganisayo. Ngaphambi kokuthi ubophe impendulo, funda kabusha ama-inputhi ubuze ukuthi iyiphi ekhawulela umphumela nangomuphi umthetho.

Umkhuba osheshayo wenza lokhu kube yinto ejwayelekile: eduze kwempendulo ngayinye, qaphela i-inputhi ekhawulelayo nomthetho owusebenzisile, izindawo zamadesimali noma inani lezinombolo. Uma impendulo ikhombisa izinombolo eziningi kunalezo i-inputhi ezigunyazayo, yiyise; uma ikhombisa ezimbalwa, bheka i-zero ehlala ngemuva isibali esiyilahlile.

• Ukuvumela inombolo eqondile ukuthi ikhawulele impendulo. Isici esingu-1000 mL/L noma inombolo engu-2 ayiwancishisi neze amanani ezinombolo ezibalulekile.
• Ukusebenzisa umthetho wokuphindaphinda esambeni. Izamba nokwehluka zikhawulelwa izindawo zamadesimali, hhayi inani lezinombolo.
• Ukuyisa wonke inani eliphakathi. Gcina izinombolo zokulondoloza bese uyisa kanye ekugcineni.
• Ukulahla ama-zero ahlala ngemuva abalulekile. Isibali sikhombisa u-2.5 lapho isilinganiso besingu-2.50 mL; buyisela i-zero.
• Ukubala ama-zero angaphambili. U-0.0081 g unezinombolo ezibalulekile ezimbili, hhayi ezine.
• Ukubika inombolo ephelele ene-zero engaqondakali. Bhala u-3.40 × 10² g kunokuba ubhale u-340 g lapho izinombolo ezintathu zibalulekile.