己烷的同分异构体有几个？

CH3-(CH2)4-CH3 己烷
CH3CH(CH3)-(CH2)2-CH3 2-甲基戊烷
CH3CH2CH(CH3)CH2CH3 3-甲基戊烷
CH3C(CH3)2CH2CH3 2,2-二甲基丁烷
CH3CH(CH3)CH(CH3)2 2,3-二甲基丁烷

有以上5种

己烷：
CH3-(CH2)4-CH3
CH3CH(CH3)-(CH2)3-CH3
CH3CH2CH(CH3)-(CH2)2-CH3
CH3CH(CH3)CH(CH3)CH2CH2CH3
CH3CH(CH3)CH2CH(CH3)CH2CH3
CH3CH(CH3)CH2CH2CH(CH3)CH3
CH3CH(CH3)CH(CH3)CH(CH3)CH3

5 个

5种
正己烷；2-甲基戊烷；3甲基戊烷；2，2-甲基丁烷；2，3甲基丁烷

5个