Qhov sib txawv tseem ceeb ntawm cov saw hlau ncaj thiab cov ceg ntoo alkanes yog tias nyob rau hauv cov saw hlau ncaj nraim, tag nrho cov pa roj carbon atoms sib txuas ua ke ua cov saw txuas txuas ntxiv thaum cov saw hlau txuas txuas txuas nrog cov hlua txuas txuas mus ntxiv.
Alkanes yog hydrocarbon tebchaw uas muaj cov pa roj carbon thiab hydrogen atoms uas tsuas yog ib daim ntawv cog lus ntawm lawv (tsis muaj ob daim ntawv cog lus lossis triple daim ntawv cog lus ntawm carbon atoms). Raws li lawv cov qauv, muaj ob hom alkanes raws li cov saw ncaj alkanes thiab branched-chain alkanes.
Dab tsi yog cov saw ncaj Alkanes?
Ncaj saw alkanes yog cov hydrocarbon tebchaw uas muaj cov saw txuas txuas ntxiv ntawm carbon atoms txuas nrog hydrogen atoms. Alkanes yog cov tebchaw uas tsuas muaj ib daim ntawv cog lus ntawm carbon atoms. Ncaj saw alkanes yog aliphatic vim hais tias tsis muaj lub nplhaib cov qauv los yog unsaturation nyob rau hauv cov tebchaw. Ntxiv mus, ncaj-chain alkanes yog saturated compounds vim tsis muaj ob los yog triple bonds ntawm carbon atoms.
Daim duab 01: Ib Txoj Cai Ncaj Ncees Alkane Structure
Cov mis mos molecular ntawm cov tshuaj no ua raws li tus qauv CnH2n+2 Tsis muaj cov hlua khi lossis pawg pendant txuas nrog cov kab txuas txuas ntxiv ntawm cov molecules no. Thaum naming ib tug ncaj saw alkane, peb yuav tsum tau siv lub prefix uas qhia cov naj npawb ntawm carbon atoms nyob rau hauv lub molecule thiab lub npe xaus nrog "-ane", uas qhia tau hais tias nws yog ib tug alkane. Piv txwv li, cov saw hlau ncaj nraim uas muaj tsib carbon atoms tau txais lub npe "pentane" (pent + ane).
Dab tsi yog Branched Chain Alkanes?
Branched saw alkanes yog cov hydrocarbon compounds uas muaj cov pab pawg sab txuas nrog cov saw hlau txuas ntxiv. Cov chains sab no yog hu ua ceg. Yog li ntawd, cov tebchaw no tsis yog linear hydrocarbons. Txij li thaum lawv yog alkanes, tsis muaj ob los yog triple bonds ntawm carbon atoms. Yog li ntawd, cov molecules yog saturated compounds. Cov ceg uas muaj nyob rau hauv cov molecules muaj xws li methyl, ethyl, propyl, thiab lwm yam.
Thaum naming a branched-chain alkane, lub nomenclature system txawv tshaj qhov ncaj saw alkane nomenclature. Ntawm no, peb yuav tsum qhia cov npe ntawm cov ceg thiab. Lub npe ntawm cov saw txuas txuas ntxiv yog hu ua qia npe. Thaum lub npe ntawm cov ceg ntoo, peb yuav tsum siv cov lus "-yl" tsis yog "-ane" nrog rau cov naj npawb ntawm cov pa roj carbon atoms hauv ceg. Piv txwv li, methyl, ethyl, thiab lwm yam. Txawm li cas los, naming ib tug loj branched-chain alkane yog nyuaj npaum li cas. Yog li ntawd, nws yog ib qho tseem ceeb kom nco ntsoov cov kauj ruam hauv qab no;
- Ua ntej, nrhiav qhov ntev tshaj plaws thiab txuas txuas carbon saw (stem saw) thiab npe nws.
- Nrhiav cov hlua sab thiab npe lawv ib yam.
- Muab cov lej rau txhua cov pa roj carbon atom hauv txoj hauv kev uas cov saw hlau sab tau txais tus lej qis tshaj.
- Sau cov npe ntawm cov saw hlau sab hauv cov ntawv sau.
- Siv tus hyphen los cais cov lej ntawm cov saw hlau ntawm qia lub npe.
- Piv txwv li, ib ceg alkane muaj ib pawg methyl ntawm 2 nd carbon ntawm propane molecule tau txais lub npe "2-methylpropane".
Dab tsi yog qhov txawv ntawm Ncaj thiab ceg saw Alkanes?
Alkanes yog hydrocarbon tebchaw nrog carbon thiab hydrogen atoms uas tsuas muaj ib daim ntawv cog lus ntawm lawv. Tsis tas li ntawd, muaj ob hom alkanes li ncaj-chain alkanes thiab branched-chain alkanes. Qhov sib txawv tseem ceeb ntawm cov saw ncaj thiab cov ceg ntoo alkanes yog cov saw hlau ncaj nraim alkanes, tag nrho cov pa roj carbon atoms sib txuas ua ke ua cov saw txuas txuas ntxiv thaum cov saw saw hlau alkanes muaj cov hlua txuas txuas rau cov saw hlau txuas ntxiv.
Hauv qab infographic qhia cov ntsiab lus ntxiv ntawm qhov sib txawv ntawm cov saw ncaj thiab ceg ntoo alkanes.
Summary – Ncaj nraim vs ceg saw Alkanes
Alkanes yog cov hydrocarbon tebchaw uas muaj cov pa roj carbon thiab hydrogen atoms uas tsuas muaj ib daim ntawv cog lus ntawm lawv. Raws li lawv cov qauv, muaj ob hom alkanes li ncaj-chain alkanes thiab branched-chain alkanes. Qhov sib txawv tseem ceeb ntawm cov saw ncaj thiab cov ceg ntoo alkanes yog cov saw hlau ncaj nraim alkanes, tag nrho cov pa roj carbon atoms sib txuas ua ke ua cov saw txuas txuas ntxiv thaum cov saw saw hlau alkanes muaj cov hlua txuas txuas rau cov saw hlau txuas ntxiv.
