12.26. An alkane has 20 hydrogen atoms. How many carbon atoms would it contain if it were (a) a straight-chain alkane (b) a branched-chain alkane (c) a cycloatkane? 12.30 Label each pair of compounds as constitutional isomers, identical molecules, or not isomers of each other. CH3CH2CH2CH3andCH3CH2CH2CH2CH3 a. b. c. d. and 12.34 Consider compounds AE and label each pair of compounds as identical molecules, constitutional isomers, or not isomers of each other: (a) A and B (b) A and C (c) B and D (d) D and E (e) B and E A B C D E 12.36/41. Draw the five constitutional isomers having molecular formula C6H14. Under each drawing give the IUPAC name of the compound. 12.46. Give the IUPAC name for each compound. a. b. c. d. (CH3CH2)2CHCH(CH2CH3)2 e. f. 12.48 Give the IUPAC name for each cycloalkane. a