The article "Scaling properties of adsorption energies for hydrogen-containing molecules on transition-metal surfaces" by Abild-Pedersen et al. (2007) presents density functional theory (DFT) calculations to investigate the adsorption energies of CH$_x$, NH$_x$, OH$_x$, and SH$_x$ molecules on various transition-metal surfaces. The authors find that the adsorption energy of these molecules scales approximately with the adsorption energy of the central atom (C, N, O, or S), with the scaling constant depending only on the number of hydrogen atoms (x). A model is proposed to explain this behavior, suggesting that the adsorption energy is influenced by the valency of the adsorbate and the properties of the d electrons of the surface. The model is further developed into a framework for estimating reaction energies for hydrogenation and dehydrogenation reactions of organic molecules on transition-metal surfaces. The model is tested against full DFT calculations for hydrocarbons, alcohols, thiols, and amino acids, showing good agreement. This work provides a useful tool for screening potential catalysts by estimating reaction energies based on the adsorption energies of a few reference systems.The article "Scaling properties of adsorption energies for hydrogen-containing molecules on transition-metal surfaces" by Abild-Pedersen et al. (2007) presents density functional theory (DFT) calculations to investigate the adsorption energies of CH$_x$, NH$_x$, OH$_x$, and SH$_x$ molecules on various transition-metal surfaces. The authors find that the adsorption energy of these molecules scales approximately with the adsorption energy of the central atom (C, N, O, or S), with the scaling constant depending only on the number of hydrogen atoms (x). A model is proposed to explain this behavior, suggesting that the adsorption energy is influenced by the valency of the adsorbate and the properties of the d electrons of the surface. The model is further developed into a framework for estimating reaction energies for hydrogenation and dehydrogenation reactions of organic molecules on transition-metal surfaces. The model is tested against full DFT calculations for hydrocarbons, alcohols, thiols, and amino acids, showing good agreement. This work provides a useful tool for screening potential catalysts by estimating reaction energies based on the adsorption energies of a few reference systems.