it is an ester because of the-COOR functional groupyou name starting from right to left 3carbons is propyl, which are after the -COO. and there are 2 carbonatoms at the beginning representing the R group. 2 carbon atoms isethyl Solution it is an ester because of the-COOR functional groupyou name starting from right to left 3carbons is propyl, which are after the -COO. and there are 2 carbonatoms at the beginning representing the R group. 2 carbon atoms isethyl.