1. Structural Isomers C - C - C - C - C - C - C - C CC C - C - C - C - C - C - C C C C

2. Structural isomers: Compounds with same molecular formula but different structural formula. Isomers differ in their properties such as boiling point and melting point. More branched the structure, lower its boiling point - Closer compounds stack, stronger the IMFs. branched unbranched

3. butane 2-methylpropane C 4 H 10 isomers

4. More carbon atoms - more structural isomers. Octane - 18 different structural isomers Decane - 75 Eicosane - 366 319 (20 carbon alkane) 3-methyl-5-ethylheptane decane C - C - C - C - C - C - C C C C C - C - C - C - C CC C C C

5. Draw and name 2 structural isomers of pentane. C - C C C - C - C C C - C 2-methylbutane 2,2-dimethylpropane C - C C C - C - C C C - pentane2-methylbutane Take care when naming your isomers to be sure you don’t have the same thing.

6. 3-ethyl-2-methylhexane is a structural isomer of which straight chained alkane? 6 carbons + 2 carbons + 1 carbon = 9 carbons The alkane with 9 carbons is nonane. hexane ethyl methyl C - C - C - C C C C - 123456 C

7. CYCLOALKANES Same naming rules – but add prefix“cyclo” Name the carbon ring first, then number the carbons so as to give the alkyl groups the lowest set of numbers. 1,2-dimethylcyclopentane 1-methylcyclobutane C C C C C C CC C C C C C C CC C C cyclohexane