The everyday routine of most chemists is dictated by large numbers. The chemical rules for ensembles of molar size (N approximately N(A)=6.022 x 10(23)) are well known and can be understood in most cases by using Boltzmann distribution. It is an interesting question how a small ensemble of a chemical system behaves and if it differs from the respective large-ensemble counterpart. The experimental approach presented in the current paper involves the division of a macroscopic volume into compartments that contain only a small number of reactants. The compartments represent the pores of tailor-made nanoporous materials.