Problem : How many isomers are there for the molecular formulas below? (a) C4H8
(b) C3H4

Draw the isomers, including both constitutional isomers and stereoisomers.

(a)Since C4H8 follows the general formula CnH2n, it must contain either a double bond or a ring. (b) The unsaturation number of C3H4 = 2. It therefore contains either one triple bond, or one ring and one double bond, or two double bonds. There aren't enough C's to form two rings.

Problem : Identify whether the alkanes below are identical to A, an isomer of A, or neither.

(a) isomer (b) identical (c) neither (d) neither

Problem : Give IUPAC names for the following molecules:

(a) 3-ethylpentane
(b) 5-ethyl-2,2-dimethylnonane
(c) 3-ethyl-2-methylhexane
(d) 2,2,3,3-tetramethylpentane