Write structural formulae for the following compounds:
$(a)$ $1-$bromoheptane
$(b)$ $5-$bromoheptanoic acid

(N/A) $1-$bromoheptane: The parent chain is heptane ($7$ carbons). $A$ bromine atom is attached to the $1^{st}$ carbon.
$CH_2Br-CH_2-CH_2-CH_2-CH_2-CH_2-CH_3$
$(b)$ $5-$bromoheptanoic acid: The parent chain is heptanoic acid ($7$ carbons,including the carboxylic acid carbon). $A$ bromine atom is attached to the $5^{th}$ carbon.
$CH_3-CH_2-CH(Br)-CH_2-CH_2-CH_2-COOH$