Qhov Tseem Ceeb - Kev Txiav Txim Siab vs Molecularity
Tshuaj tiv thaiv yog kev hloov pauv uas tshwm sim hauv cov tshuaj lom neeg. Nws ua rau kev hloov ntawm ib yam tshuaj mus rau lwm tus. Thawj cov tebchaw uas tau txais cov tshuaj tiv thaiv tshuaj hu ua reactants. Qhov peb tau txais thaum ua tiav cov tshuaj tiv thaiv yog cov khoom. Kev txiav txim ntawm cov tshuaj tiv thaiv yog muab nrog kev hwm rau ib yam khoom; nws tuaj yeem ua tau raws li cov khoom siv reactant, khoom lossis catalyst. Qhov kev txiav txim ntawm cov tshuaj tiv thaiv nrog kev hwm rau ib yam khoom yog tus exponent uas nws concentration nyob rau hauv tus nqi sib npaug yog tsa. Lub molecularity ntawm cov tshuaj tiv thaiv kab mob qhia ntau npaum li cas reactant molecules koom nrog cov tshuaj tiv thaiv. Qhov txawv ntawm qhov kev txiav txim ntawm cov tshuaj tiv thaiv thiab molecularity yog qhov kev txiav txim ntawm cov tshuaj tiv thaiv muab kev sib raug zoo ntawm cov concentration ntawm ib hom tshuaj thiab cov tshuaj tiv thaiv nws undergoes whereas molecularity qhia tias muaj pes tsawg reactant molecules koom nyob rau hauv cov tshuaj tiv thaiv.
Kev Txiav Txim Siab yog dab tsi
Qhov kev txiav txim ntawm cov tshuaj tiv thaiv nrog kev hwm rau ib yam khoom yog tus exponent uas nws concentration nyob rau hauv tus nqi sib npaug yog tsa. Yuav kom nkag siab txog lub tswv yim no, peb yuav tsum xub paub tias txoj cai lij choj yog dab tsi.
Rate Law
Txoj cai lij choj qhia tias tus nqi ntawm kev nce qib ntawm cov tshuaj tiv thaiv tshuaj (ntawm qhov kub tsis tu ncua) yog proportional rau cov concentrations ntawm reactants tsa rau cov exponents uas tau txiav txim siab sim. Cov exponents no hu ua kev txiav txim ntawm cov concentrations. Cia peb xav txog ib qho piv txwv.
2N2O5 ↔ 4 NO2 + O 2
Rau cov lus teb saum toj no, tus nqi sib npaug yog muab raws li hauv qab no.
Rate=k.[N2O5x
Nyob rau hauv kab zauv saum toj no, k yog proportionality tas li uas yog hu ua tus nqi tas mus li. Nws yog qhov ntsuas kub tsis tu ncua. Cov brackets yog siv los qhia tias nws yog qhov concentration ntawm cov reactant. Lub cim x yog qhov kev txiav txim ntawm cov tshuaj tiv thaiv nrog kev hwm rau cov reactant. Tus nqi ntawm x yuav tsum tau txiav txim siab sim. Rau qhov kev tshwm sim no, nws tau pom tias x=1. Ntawm no, peb tuaj yeem pom tias qhov kev txiav txim ntawm cov tshuaj tiv thaiv tsis sib npaug rau stoichiometry ntawm cov tshuaj tiv thaiv. Tab sis hauv qee qhov kev xav, qhov kev txiav txim ntawm cov tshuaj tiv thaiv tuaj yeem sib npaug rau stoichiometry.
Rau qhov tshuaj tiv thaiv uas muaj ob lossis ntau dua reactants, tus nqi txoj cai sib npaug tuaj yeem sau raws li hauv qab no.
A + B + C ↔ P
Rate=k.[A]a[B]b[C]c
a, b thiab c yog kev txiav txim ntawm cov tshuaj tiv thaiv nrog rau A, B thiab C reactants, feem. Rau qhov sib npaug ntawm tus nqi no (muaj ntau qhov kev txiav txim ntawm cov tshuaj tiv thaiv), cov lej ntawm qhov kev txiav txim ntawm cov tshuaj tiv thaiv yog muab raws li qhov kev txiav txim tag nrho ntawm cov tshuaj tiv thaiv.
Overall order=a + b + c
Daim duab 1: Tus nqi ntawm Thawj Kev Txiav Txim thiab Kev Txiav Txim Thib Ob
Raws li qhov kev txiav txim ntawm cov tshuaj tiv thaiv, muaj ntau hom kev tshwm sim:
- Zero Order Reactions (qhov kev txiav txim ntawm cov tshuaj tiv thaiv yog xoom nrog rau cov reactant siv. Yog li cov tshuaj tiv thaiv tsis nyob ntawm qhov ntau ntawm cov reactants siv.)
- Thawj Kev Txiav Txim Siab (tus nqi yog proportional rau qhov concentration ntawm ib reactant)
- Kev Txiav Txim Thib Ob (tus nqi ntawm cov tshuaj tiv thaiv yog proportional rau lub square ntawm cov concentration ntawm ib reactant los yog rau cov khoom ntawm concentrations ntawm ob reactants)
Dab tsi yog Molecularity
Molecularity ntawm cov tshuaj tiv thaiv yog tus naj npawb ntawm cov molecules lossis ions uas koom nrog cov tshuaj tiv thaiv raws li reactants. Qhov tseem ceeb tshaj, cov reactants suav hais tias yog cov uas koom nrog hauv kev txiav txim siab theem ntawm tag nrho cov tshuaj tiv thaiv. Tus nqi txiav txim cov kauj ruam ntawm cov tshuaj tiv thaiv yog qhov qeeb tshaj plaws ntawm cov tshuaj tiv thaiv tag nrho. Qhov no yog vim cov kauj ruam qeeb tshaj plaws txiav txim siab tus nqi ntawm cov tshuaj tiv thaiv.
Daim duab 2: Ib qho Kev Sib Tham Tsis Muaj Tshuaj
Lub molecularity tuaj yeem muaj ntau hom:
- Cov tshuaj tiv thaiv tsis muaj tshuaj muaj ib qho reactant molecule (los yog ion)
- Cov tshuaj tiv thaiv bimolecular muaj ob lub reactants (ob lub reactants tuaj yeem yog tib lub tebchaw lossis sib txawv sib xyaw)
- Trimolecular cov tshuaj tiv thaiv muaj peb lub reactants.
Qhov txawv ntawm Kev Txiav Txim Siab thiab Molecularity yog dab tsi?
Kev Txiav Txim Siab vs Molecularity |
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| Qhov kev txiav txim ntawm cov tshuaj tiv thaiv nrog kev hwm rau ib yam khoom yog tus exponent uas nws cov concentration nyob rau hauv tus nqi sib npaug yog tsa. | Molecularity ntawm cov tshuaj tiv thaiv yog tus naj npawb ntawm cov molecules lossis ions uas koom nrog cov tshuaj tiv thaiv raws li reactants. |
| Kev sib raug zoo nrog cov neeg ua haujlwm | |
| Kev txiav txim ntawm cov tshuaj tiv thaiv piav qhia seb qhov concentration ntawm cov reactants cuam tshuam li cas ntawm cov tshuaj tiv thaiv. | Molecularity muab tus naj npawb ntawm cov reactants uas koom nrog cov tshuaj tiv thaiv. |
Summary – Order of Reaction vs Molecularity
Txoj cai lij choj qhia tias tus nqi ntawm kev nce qib ntawm cov tshuaj tiv thaiv tshuaj (ntawm qhov kub tsis tu ncua) yog proportional rau cov concentrations ntawm reactants tsa rau cov exponents uas tau txiav txim siab sim. Kev txiav txim ntawm cov tshuaj tiv thaiv yog muab nrog kev hwm rau tus reactant. Nws piav qhia txog qhov kev cia siab ntawm cov tshuaj tiv thaiv tus nqi ntawm cov concentration ntawm cov reactants. Qhov sib txawv tseem ceeb ntawm kev txiav txim ntawm cov tshuaj tiv thaiv thiab molecularity yog qhov kev txiav txim ntawm cov tshuaj tiv thaiv muab kev sib raug zoo ntawm cov concentration ntawm ib hom tshuaj thiab cov tshuaj tiv thaiv nws undergoes whereas molecularity qhia ntau npaum li cas reactant molecules koom nyob rau hauv cov tshuaj tiv thaiv.
