Qhov Tseem Ceeb Qhov txawv - Bond Moment vs Dipole Moment
Cov nqe lus cog lus lub sijhawm thiab lub sijhawm dipole yog raws li cov qauv zoo sib xws tab sis txawv raws li daim ntawv thov. Lub sij hawm daim ntawv cog lus tseem hu ua daim ntawv cog lus dipole lub sij hawm. Nws yog qhov polarity ntawm cov tshuaj lom neeg daim ntawv cog lus uas nyob hauv ib qho molecule. Dipole lub sij hawm, ntawm qhov tod tes, yog txhua yam kev sib cais hluav taws xob (kev sib cais ntawm cov nqi). Qhov sib txawv tseem ceeb ntawm lub caij cog qoob loo thiab lub sijhawm dipole yog lub caij cog qoob loo tshwm sim hauv cov khoom siv tshuaj lom neeg thaum lub sij hawm dipole tshwm sim ntawm ob ions hauv daim ntawv cog lus ionic lossis nruab nrab ntawm ob lub atoms hauv daim ntawv cog lus covalent.
Bond Moment yog dab tsi?
Lub sijhawm cog lus yog kev sib cais ntawm cov nqi hluav taws xob hauv cov khoom siv tshuaj lom neeg uas muaj nyob hauv qee cov tshuaj lom neeg. Li no, nws muab lub polarity ntawm ib tug chemical bond. Lub sij hawm daim ntawv cog lus tshwm sim thaum muaj qhov zoo thiab qhov tsis zoo sib cais nyob rau hauv daim ntawv cog lus tshuaj. Lub sij hawm daim ntawv cog lus dipole yog denoted los ntawm lub cim “μ”.
μ=δd
nyob rau hauv uas, δ yog tus nqi ntawm tus nqi thiab d yog qhov kev ncua deb ntawm ob lub atoms hauv covalent daim ntawv cog lus. Nyob rau hauv lub creation ntawm ib daim ntawv cog lus dipole lub sij hawm, cov hluav taws xob nqi raug cais raws li ib feem nqi δ + thiab δ-. Qhov kev sib cais ntawm tus nqi no tshwm sim hauv cov khoom siv tshuaj lom neeg thaum ob lub atoms koom nrog kev tsim cov ntawv cog lus muaj qhov sib txawv electronegativity qhov tseem ceeb. Txij li thaum lub electronegativity ntawm ib lub atom yog affinity rau electrons, ntau electronegative atoms nyiam daim ntawv cog lus electrons ntawm lawv. Tom qab ntawd, lub atom nrog tus nqi qis dua electronegative tau txais ib feem ntawm qhov zoo vim tias qhov ceev ntawm electrons nyob ib ncig ntawm lub atom tsawg dua. Ua ke, lub atom uas muaj electronegativity siab tau txais ib feem tsis zoo nqi.
Daim duab 1: Polarity ntawm Boron trifluoride (BF3)
Lub SI unit rau kev ntsuas ntawm daim ntawv cog lus dipole lub sij hawm yog Coulomb-meter (C m). Ib lub diatomic molecule muaj tsuas yog ib daim ntawv cog lus. Yog li ntawd, daim ntawv cog lus dipole lub sij hawm ntawm ib tug diatomic molecule zoo ib yam li lub sij hawm molecular dipole. Lub sijhawm molecular dipole rau diatomic molecules uas muaj ob lub atom zoo sib xws yog xoom, piv txwv li, lub sijhawm molecular dipole ntawm Cl2 yog xoom. Tab sis cov ionic tebchaw xws li KBr muaj lub sijhawm siab thiab lub sijhawm molecular. Rau complex polyatomic molecules, muaj ntau covalent bonds. Tom qab ntawd lub sijhawm molecular dipole yog txiav txim siab los ntawm txhua tus neeg daim ntawv cog lus dipole lub sijhawm.
Dipole Moment yog dab tsi?
Dipole lub sijhawm yog kev sib cais ntawm cov nqi hluav taws xob. Kev sib cais ntawm tus nqi yuav tshwm sim ntawm ob ions hauv daim ntawv cog lus ionic lossis ob lub atoms hauv covalent chemical bond. Lub sijhawm dipole tshwm sim vim qhov sib txawv ntawm cov txiaj ntsig electronegativity ntawm cov atom sib txawv uas tsim cov ntawv cog lus tshuaj. Qhov ntau dua qhov sib txawv ntawm cov txiaj ntsig electronegativity, ntau dua lub sijhawm dipole. Lub sijhawm dipole ntsuas qhov polarity ntawm ib lub molecule. Lub sijhawm dipole ntawm lub molecule yog xam los ntawm kev sib npaug hauv qab no.
μ=Σq.r
qhov twg μ yog lub sijhawm dipole, q yog qhov loj ntawm tus nqi thiab r yog txoj haujlwm ntawm tus nqi. Ntawm no, μ thiab r yog vectors, uas yog ntau muaj kev taw qhia nrog rau qhov loj.
Daim duab 2: Dipole Moment of Propane
Tab sis qee zaum, lo lus dipole lub sijhawm yog siv los ua lub npe ntsuas ntawm qhov sib nqus polarity ntawm ib qho kev them nqi. Lub sijhawm sib nqus dipole txiav txim siab lub zog uas cov hlau nplaum tau ntsib hauv qhov chaw sib nqus sab nraud. (Torque=moment; lub zog tig).
Dab tsi yog qhov Zoo sib xws Bond Moment thiab Dipole Moment?
- Ob leeg siv los ntsuas qhov polarity (uas yog tsim los ntawm kev sib cais)
- Ob leeg ntsuas hauv chav tsev Debye (D) uas yog sib npaug rau coulomb-meter (C m).
Qhov txawv ntawm Bond Moment thiab Dipole Moment yog dab tsi?
Bond Moment vs Dipole Moment |
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| Lub sijhawm cog lus yog kev sib cais ntawm cov nqi hluav taws xob hauv cov tshuaj lom neeg cov khoom siv uas muaj nyob rau hauv ib qho tshuaj lom neeg. | Dipole lub sijhawm yog kev sib cais ntawm cov nqi hluav taws xob. |
| ntsuas | |
| Lub sijhawm cog lus ntsuas qhov polarity ntawm daim ntawv cog lus tshuaj. | Dipole lub sijhawm ntsuas qhov polarity ntawm cov tshuaj lom neeg lossis cov molecule. |
| Lub sijhawm cog qoob loo tshwm sim hauv daim ntawv cog lus tshuaj lom neeg. | Dipole lub sijhawm tshwm sim ntawm ob ions hauv ib daim ntawv cog lus ionic lossis nruab nrab ntawm ob lub atom hauv cov nyiaj sib cog lus hauv cov molecule. |
Summary – Bond Moment vs Dipole Moment
Lub caij cog qoob loo thiab lub sijhawm dipole yog cov ntsiab lus cuam tshuam thaum nws los txog rau lub polarity ntawm cov tshuaj bonds hauv cov molecules lossis ionic compounds. Qhov sib txawv tseem ceeb ntawm lub caij cog qoob loo thiab lub sijhawm dipole yog lub caij cog qoob loo tshwm sim hauv covalent tshuaj daim ntawv cog lus thaum lub sij hawm dipole tshwm sim ntawm ob ions hauv daim ntawv cog lus ionic lossis nruab nrab ntawm ob lub atoms hauv daim ntawv cog lus covalent.
