An apparatus for performing physical and/or chemical operations comprising holding means (3) provided with openings (2) for an array of reactor vessels (1); reactor vessels (1) positioned totally or partly within the openings (2), and connection means (5) capable of connecting the reactor vessels (1) and the holding means (3), which connection means (5) are located on or in the holding means (3) surrounding the openings (2) in which the reactor vessels (1) are positioned. Processes which can be carried out with the apparatus comprise, inter alia, mixing, cooling, heating, centrifugation, evaporation, filtration and pressure processes.