Draw the structural formulas for the following compounds: 1) 1-pentene 2) 2-methyl-3-heptyne 3) 3-ethyl-4.5-dimethylpentane 4) 2-ethyl-1-pentanol 5) m-bromophenol 6) 3,3.6.6-tetraethyl-4-octyne 7) 4-methylhexanoic acid 8) 2.3-dichloro-4-ethyl-2-hexene 9) 2,4-dinitrotoluene 10) 3-ethyl-2,3-dimethyl-2-pentanol 11) 5-chloro-4-methyl-3-heptanone 12) 3-phenyl-1-propyne