The mass transfer behavior from single spheres within random packings was examined in order to quantify the effects of local structure and hydrodynamics on mass transfer. Results show that in the sphere packs studied. structural differences at the pore scale cause the local Peclet number to vary by more than an order of magnitude and the exponent in the Sherwood versus Peclet number relationship to vary between approximately 0.3 and 0.7, both as a function of location within the packing. These combined effects cause at least a two-fold variation in local mass transfer rates and significant differences in the sensitivity of local mass transfer rates to changes in the overall flowrate to the bed. Two distributed parameters are introduced to quantify these effects, which collapse mass transfer data onto a single curve relating the local Sherwood number to a local Peclet number. The physical significance of these parameters is discussed, which aids in our understanding of fundamental behavior in disordered systems. Finally, we show how this information is used to calculate a spatially averaged mass transfer coefficient for dispersed interfaces under conditions where the total mass transfer rate for these interfaces does not reflect average behavior for the bed.