Isibonelo Semibuzo Yengxoxo Yethiyori Yokungqubuzana
I-Pendahuluan
Ithiyori yokushayisana iwumqondo oyisisekelo kumakhemikhali ochaza ukuthi kwenzeka kanjani futhi kungani kwenzeka ukusabela kwamakhemikhali. Yaqala ukuphakanyiswa nguMax Trautz noWilliam Lewis ekuqaleni kwekhulu lama-20. Ngokwalo mbono, ukusabela kwamakhemikhali kwenzeka lapho izinhlayiya ze-reactant zishayisana ngamandla anele futhi ziqonde ngqo.
Lesi sihloko sizoxoxa ngezibonelo eziningana zezinkinga ezihlobene nethiyori yokushayisana kanye nezixazululo zazo ukuze kunikezwe ukuqonda okujulile kwalomqondo. Ekupheleni kwalesi sihloko, abafundi kufanele bakwazi ukuqonda izindlela eziyisisekelo zethiyori yokushayisana kanye nendlela yokuyisebenzisa ezimweni ezahlukene zezinkinga zekhemistri.
Ithiyori Eyisisekelo Yokungqubuzana
Ithiyori yokushayisana iphakamisa ukuthi izici ezimbili eziyinhloko zinquma ukuthi ukushayisana kuzoholela yini ekusabeleni kwamakhemikhali:
1. Amandla Okusebenza (Ea): Amandla amancane adingekayo ukuze kushayisane ama-molecule asabelayo ukuze kukhiqizwe imikhiqizo.
2. Ukuqondiswa Kwama-Molecular: Indawo yama-molecule lapho eshayisana nayo ibaluleke kakhulu. Ukushayisana kuzoholela ekuphenduleni kuphela uma ama-molecule eqondiswe kahle.
Izici Ezithonya Ithiyori Yokungqubuzana
1. Ukuhlushwa: Uma ukuhlushwa kwama-reactants kuphakeme, kulapho amathuba okungqubuzana kwama-molecule ama-reactant aphezulu khona.
2. Izinga Lokushisa: Ukwanda kwezinga lokushisa kuvame ukwandisa amandla e-kinetic ama-molecule, okungaholela ekushayisaneni okwengeziwe okunamandla angaphezu kwamandla okusebenza.
3. I-Catalyst: Umsebenzi we-catalyst ukunciphisa amandla okusebenza ukuze kube nokushayisana okwengeziwe okuphumelelayo.
Imibuzo Nezingxoxo Eziyisibonelo
Isibonelo Umbuzo 1: Umphumela Wokugxilisa Ingqondo
Umbuzo:
Uma ukuhlushwa kwe-molecule A ku-reaction `A + B -> C` kuphindwe kabili, izinga lokusabela lizoshintsha kanjani ngokwe-collision theory?
Ingxoxo:
Ngokusho kwethiyori yokushayisana, izinga lokusabela lincike ekuvameni kokushayisana phakathi kwezinhlayiya u-A no-B. Uma ukuhlushwa kuka-A kuphindwe kabili, inani lokushayisana phakathi kwama-molecule u-A no-B nalo lizokhula. Ngokuvamile, singasho ukuthi izinga lokusabela lizophindeka kabili.
Kodwa-ke, ezimweni eziningi, ukusabela kunohlelo oluyinkimbinkimbi kakhulu. Ngokusabela kwe-oda lokuqala maqondana no-A, ukuphinda kabili ukuhlushwa kuka-A kuzobangela ukuphinda kabili kwesilinganiso sokusabela:
\[ r = k[A][B] \umcibisholo ongakwesokudla r' = k[2A][B] = 2r \]
Isibonelo Umbuzo 2: Umphumela Wokushisa
Umbuzo:
Ukusabela kunamandla okusebenza angu-50 kJ/mol. Uma izinga lokushisa likhuphuka lisuka ku-300 K liye ku-310 K, izinga lokusabela lizoshintsha kanjani ngokusho kwethiyori yokushayisana kanye ne-Arrhenius factor?
Ingxoxo:
Ukwanda kwezinga lokushisa kwandisa amandla e-kinetic ama-molecule, okuholela ekutheni ama-molecule amaningi abe namandla amakhulu noma alingana namandla okusebenza. Lokhu kuvame ukuchazwa yi-Arrhenius equation:
\[
k = Ae^{-\frac{Ea}{RT}}
\]
Kuphi:
– \( k \) yisilinganiso esingaguquki sokusabela
– \( A \) kuyinto ebonakala kusengaphambili
– \( Ea \) amandla okusebenza
– \( R \) yi-gas constant (8.314 J/mol·K)
– \( T \) izinga lokushisa ku-Kelvin
Singathatha i-logarithm yemvelo ye-Arrhenius equation:
\[
\ln k = \ln A – \frac{Ea}{RT}
\]
Ukuze sibale ushintsho lwesilinganiso sokusabela, sithatha isilinganiso sama-rate constants emazingeni okushisa amabili ahlukene:
\[
\frac{k_2}{k_1} = \frac{Ae^{-\frac{Ea}{R \cdot T2}}}{Ae^{-\frac{Ea}{R \cdot T1}}} = e^{\left(-\frac{Ea}{R}\left(\frac{1}{T2} – \frac{1}{T1}\right)\right)}
\]
Ukufaka amanani anikeziwe:
\[
k_1 = Ae^{-\frac{50000}{8.314 \izikhathi ezingu-300}}
\]
\[
k_2 = Ae^{-\frac{50000}{8.314 \izikhathi ezingu-310}}
\]
Ukubala ushintsho:
\[
\frac{k_2}{k_1} = e^{\left(-\frac{50000}{8.314}\left(\frac{1}{310} – \frac{1}{300}\right)\right)}
\]
\[
= e^{\left(-6012.9 \times (-0.00010753)\right)}
\]
\[
= e^{0.646}
\]
\[
cishe 1.91
\]
Ngakho-ke, ukwandisa izinga lokushisa kusuka ku-300 K kuya ku-310 K cishe kuphinda kabili izinga lokusabela, cishe ngo-91%.
Isibonelo Umbuzo 3: Umphumela Wezikhangisi
Umbuzo:
Ekuphenduleni, ukungezwa kwe-catalyst kusheshisa ukusabela ngokunciphisa amandla okusebenza kusuka ku-75 kJ/mol kuya ku-50 kJ/mol ku-298 K. Bala isilinganiso samazinga okusabela nge-catalyst nangaphandle kwayo.
Ingxoxo:
Sebenzisa i-Arrhenius equation ukuze ubale ama-rate constant amabili:
\[
k_{uncat} = Ae^{-\frac{75000}{8.314 \izikhathi ezingu-298}}
\]
\[
k_{cat} = Ae^{-\frac{50000}{8.314 \izikhathi ezingu-298}}
\]
Bese kuthi, isilinganiso phakathi kwalezi zilinganiso ezimbili zokusabela yilesi:
\[
\frac{k_{cat}}{k_{uncat}} = \frac{e^{-\frac{50000}{8.314 \times 298}}}{e^{-\frac{75000}{8.314 \times 298}}}
\]
\[
= e^{\left(\frac{75000 – 50000}{8.314 \times 298}\right)}
\]
\[
= e^{10.075}
\]
\[
cishe 23685
\]
Lesi silinganiso sibonisa ukuthi ngokufakwa kwe-catalyst, izinga lokusabela lingakhuphuka izikhathi eziyizinkulungwane, okuyinto ebaluleke kakhulu.
Isiphetho
Ngezibonelo ezingenhla, singathola ukuqonda okujulile kokuthi ithiyori yokushayisana ichaza kanjani imiphumela yokuhlushwa, izinga lokushisa, kanye nama-catalyst esilinganisweni sokusabela kwamakhemikhali. Ngayinye yalezi zici inomthelela ohlukile futhi obalulekile emvamisa kanye namandla okushayisana, okugcina kuthonye ukuthi ukusabela kwamakhemikhali kwenzeka ngokushesha kangakanani. Ngokusebenzisa ithiyori yokushayisana, singaklama izivivinyo ezisebenza kahle kakhulu kanye nezinqubo zezimboni zamakhemikhali.
