from the earlier work. The complete dataset, including alkanes with up to 17 heavy atoms (∼32k labels), was used for the results shown in the Supplementary Information (SI). By testing this model, trained solely on an extremely restricted and simple chemical space of only saturated acyclic hydrocarbons, on experimental data for polymers and small molecules containing unsaturations, cyclic structures, and atoms like O, N, F, and Cl, we establish a baseline for the predictive power of the simplest models trained on systematic data. This approach also allows us to compare the effects of a more diverse training molecule space versus a smaller, systematically generated molecular space with kinetic data.