Qhov Tseem Ceeb Qhov Sib Txawv - Feem Xyuam Tshaj Tawm vs Feem Xyuam Rov Qab
Percent yield yog tus nqi ntawm cov khoom sib xyaw uas tau los ntawm cov tshuaj sib xyaw ua ke nrog rau qhov kev xav tau ntawm qhov xav tau. Qhov no yog tus nqi feem pua. Nws yog siv los txiav txim qhov ua tau zoo ntawm cov tshuaj tiv thaiv tshuaj. feem pua rov qab yog ib lo lus uas feem ntau siv nyob rau hauv cov organic chemistry hais txog cov txheej txheem recrystallization. Qhov feem pua rov qab yog tus nqi ntawm cov ntshiab compound nrog rau cov impure compound tau los ntawm cov tshuaj synthesis. Qhov sib txawv ntawm qhov feem pua yield thiab feem pua rov qab yog qhov feem pua yield yog xam raws li qhov piv ntawm cov txiaj ntsig tiag tiag thiab cov txiaj ntsig theoretical whereas feem pua rov qab yog xam raws li qhov piv ntawm cov ntshiab compound thiab thawj qhov sib xyaw.
Percent Yield yog dab tsi?
Percent yield yog qhov piv ntawm feem pua ntawm cov txiaj ntsig tiag tiag thiab cov txiaj ntsig theoretical ntawm cov khoom kawg tau txais los ntawm cov tshuaj synthesis. Feem ntau, qhov tseeb yield yog me dua li qhov theoretical yield vim kev sim ua yuam kev xws li tsis tiav cov tshuaj tiv thaiv, poob hauv kev rov qab los ntawm cov khoom, thiab lwm yam. Yog hais tias qhov tseeb yield yog sib npaug rau qhov theoretical yield, ces qhov feem pua yield yog 100. %
Percent Yield Calculation
Kev sib luag
Qhov sib npaug siv los xam qhov feem pua yield yog raws li hauv qab no.
Percent Yield=(Qhov tseeb tawm los / Theoretical yield) x 100%
Qee zaum, tus nqi ntawm feem pua yields tshaj 100%. Qhov no txhais tau hais tias cov khoom muaj ntau tshaj qhov xav tau los ntawm kev suav cov theoretical. Qhov no ua tau vim tias muaj peev xwm muaj qee yam tshuaj lom neeg hauv tib cov tshuaj tiv thaiv sib xyaw uas tsim cov khoom qub. Txawm li cas los xij, nws tuaj yeem yog vim muaj cov impurities.
Cia li ua piv txwv kom nkag siab txog kev suav ntawm feem pua yield.
Ex: Thaum CaCO3 (16.0 g) yog rhuab rau thermal decomposition, 7.54 g ntawm CaO tau.
Daim duab 01: Calcium Carbonate
Theoretical yield:
CaCO3 → CaO + CO2
Stoichiometry between CaCO3 and CaO is 1:1. Yog li, ib mole ntawm calcium carbonate yuav tsum muab 1 mole ntawm calcium oxide. Cov molar loj ntawm Calcium carbonate yog 100 g / mol, thiab molar loj ntawm calcium oxide yog 56 g / mol.
Yog 100g ntawm CaCO3 raug hlawv, nws muab 56 g CaO. Tab sis hauv qhov kev sim no, 16.0 g tau hlawv. Ces tus nqi CaO yuav tsum muab yog, Theoretical yield=(56 g / 100 g) x 16 g=8.96 g
Tom qab ntawd cov txiaj ntsig feem pua yuav suav tau raws li hauv qab no.
Percent yield=(7.54 g / 8.96 g) x 100%=84.16 %
Percent Recovery yog dab tsi?
Percent rov qab yog tus nqi ntawm cov khoom tau txais tom qab nws synthesis thiab purification. Qhov feem pua rov qab tuaj yeem siv los txiav txim siab qhov ua tau zoo ntawm cov tshuaj tiv thaiv synthesis. Lo lus no feem ntau yog siv hauv cov organic chemistry los txiav txim siab cov txiaj ntsig tau los ntawm recrystallization.
Cov txheej txheem recrystallization yog siv los ua kom tau cov khoom huv. Feem ntau lub sij hawm cov khoom kawg muab los ntawm cov tshuaj synthesis muaj ntau impurities. Yog li ntawd, purification yog ib kauj ruam tseem ceeb hauv cov organic synthesis tshwm sim. Nyob rau hauv cov txheej txheem recrystallization, lub compound yuav tsum tau purified yog tov nrog ib tug haum kub hnyav thiab yog stirred zoo. Tom qab ntawd nws raug tso cai kom txias. Thaum lub caij txias no, lub compound yog precipitated. Tom qab ntawd tus nqi rov qab tuaj yeem suav tau.
Percent rov qab xam
Kev sib luag
Percent rov qab=(Tus nqi ntawm cov purified compound / tus nqi ntawm thawj compound) x 100%
Ntawm no, tus nqi ntawm cov tshuaj purified txhais tau hais tias tus nqi ntawm cov khoom tsim tom qab cov txheej txheem recrystallization. Tus nqi ntawm cov khoom qub txhais tau tias, tus nqi ntawm cov khoom tsis huv coj mus rau recrystallize.
Cia peb xav txog qhov piv txwv kom nkag siab txog kev suav ntawm feem pua yield.
Daim duab 02: Ib Pure Cinnamic Acid Sample tom qab Recrystallization
Ex: Yog tias 14 g ntawm tooj liab tau siv hauv cov txheej txheem recrystallization thiab cov tooj liab rov qab thaum kawg ntawm cov txheej txheem yog 12 g, Percent rov=(12 g / 14 g) x 100%=85.71 %
Dab tsi yog qhov zoo sib xws ntawm Kev Tshaj Tawm Tshaj Lij Tshaj Lij Tshaj Lij Tshaj Lij Tshaj Lij Tshaj Lij Tshaj Lij Tshaj Lij Tshaj Lij Tshaj Lij Tshaj Lij Tshaj Tawm?
Ob qho piv txwv cov txiaj ntsig thiab cov ntsiab lus rov qab feem pua yog feem pua uas yog qhov sib piv ntawm 100%
Qhov txawv ntawm Qhov Ib Feem Xyuam Tshaj Tawm thiab Feem Xyuam rov qab yog dab tsi?
Percent Yield vs Percent Recovery |
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| Percent yield yog qhov piv ntawm feem pua ntawm cov txiaj ntsig tiag tiag thiab cov txiaj ntsig theoretical ntawm cov khoom kawg tau txais los ntawm cov tshuaj synthesis. | Percent rov qab yog tus nqi ntawm cov khoom tau txais tom qab nws synthesis thiab purification. |
| Lub Hom Phiaj | |
| Percent yield tuaj yeem siv los txiav txim siab qhov ua tau zoo ntawm cov tshuaj synthesis. | Percent rov qab yog siv los txiav txim siab tus nqi ntawm cov tshuaj dawb huv tam sim no hauv cov khoom kawg ntawm cov tshuaj synthesis. |
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Kev sib npaug rau kev xam | |
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Percent yield yog xam raws li qhov piv ntawm qhov tseeb yield thiab theoretical yield. Percent Yield=(Qhov tseeb tawm los / Theoretical yield) x 100% |
Percent rov qab yog xam raws li qhov piv ntawm cov ntshiab compound thiab thawj compound. Percent rov qab=(Tus nqi ntawm cov purified compound / tus nqi ntawm thawj compound) x 100% |
Summary – Feem pua Yield vs Feem pua rov
Percent yield thiab feem pua rov qab yog ob nqe lus uas siv los qhia tus nqi lossis qhov purity ntawm cov khoom kawg uas tau txais los ntawm cov tshuaj tiv thaiv kev sib txuas. Qhov sib txawv ntawm qhov feem pua yield thiab feem pua rov qab yog qhov feem pua yield yog xam raws li qhov sib piv ntawm qhov tseeb tawm los thiab cov theoretical yield whereas feem pua rov qab yog xam raws li qhov piv ntawm cov ntshiab compound thiab thawj compound.
