The transient mass transfer from a binary gas bubble to an incompressible liquid accompanied by a chemical reaction into the liquid phase is analysed numerically. Only one of the bubble components transfers into the liquid phase where a first-order, irreversible chemical reaction occurs. The concentration of the transferring species inside the bubble is considered spatially uniform but not constant in time. Creeping flow was assumed. The mathematical model equations were solved numerically in spherical coordinates system. The computations focused on the influence of the Damkohler number and Henry number on the mass transfer rate for Pe = 10, 100, 1000 and Da/Pe = 0.1, 1, 10. (C) 2012 Elsevier Ltd. All rights reserved.