A C-O stretch is typically observed around 1150 cm -1, and the backpropagation plots for carboxylic acids, alcohols, and esters indicate a peak in this region is used by our model for each of these functional groups. Additionally, a strong C=O peak is typically observed for carbonyl compounds near 1600 cm -1 , but the model only placed importance on this peak for the amide functional group. The example alcohol compound contained both an alcohol group and a carboxylic acid, and the model ignored the C=O in the prediction of the alcohol, instead placing importance on peaks corresponding to the O-H stretch near 3500 cm -1 . These results show that the model reproduces the 'known chemistry' of functional group features without explicit input of peak to functional group relationships.