Write a structural formula for each of the following compounds:
(a) Octanoic acid
(b) Propanamide
(c) N, N-Diethylhexanamide
(d) 2-Methyl-4-hexenoic acid
(e) Butanedioic acid
(f) 1, 2-Benzenedioic acid (phthalic acid)
(g) 1,4-Benzenedioic acid (terephthalic acid)
(h) Acetic anhydride
(i) Isobutyl propanoate
(j) Benzyl acetate
(k) Ethanoyl chloride (acetyl chloride)
(l) 2-Methylpropanenitrile
(m) Ethyl 3-oxobutanoate (ethyl acetoacetate)
(n) Diethyl propanedioate (diethyl malonate)