Cov qauv tseem ceeb ntawm cov pa roj carbon ntau ntxiv (homologues, cov qauv zoo sib xws): Feem ntau hais lus, raws li tus naj npawb ntawm cov pa roj carbon atoms hauv aliphatic hydrocarbon molecule nce, lub melting point feem ntau qhia ib tug gradual upward trend. Qhov laj thawj tseem ceeb yog qhov txheeb ze molecular loj zuj zus, thiab van der Waals rog ntawm cov molecules maj mam ntxiv dag zog. Piv txwv los xyuas qhov no:
Table: Npe|Tus naj npawb ntawm Carbon Atoms|Melting Point (zeeg)
Ethane|2|-183.3
Propane|3|-187.7
Butane|4|-138.4
Pentane|5|-129.7
Propane qhia kev hloov pauv me ntsis vim yog siv lead ua, tab sis tag nrho cov qauv tseem ua raws li tus qauv nce.
Cov qauv ntawm tib tus naj npawb ntawm cov pa roj carbon atoms (isomers, tib cov txheeb ze molecular loj): Thaum aliphatic hydrocarbons muaj tib cov pa roj carbon atoms (ie, yog isomers), tus qauv yog: ntau ceg, qhov qis dua qhov melting point. Qhov no yog vim hais tias ntau ceg ua rau kom tsawg compact molecular kev npaj, tsis muaj zog intermolecular rog, thiab yog li ntawd ib tug qis melting point.
Cov Lus Cim Tshwj Xeeb
Ntxiv nrog rau cov cai saum toj no, ob lub ntsiab lus yuav tsum tau saib xyuas tshwj xeeb:
Txawm hais tias neopentane muaj 5 carbon atoms (nyob rau hauv cov kua ntau yam), nws yog gaseous nyob rau hauv chav tsev kub, thiab nws melting thiab boiling cov ntsiab lus yog qis dua cov ncaj - chain pentane, ua raws li txoj cai hais tias ntau branched lub isomer, qhov qis ntawm boiling thiab melting ntsiab lus;
Tag nrho cov aliphatic hydrocarbons muaj qhov ntom ntom tsawg dua dej, cov cuab yeej uas tsis hloov nrog cov pa roj carbon atoms.