Select a reasonable explanation to account for the differences. There may be more than one possible reason that makes sense, just select one of them. It is possible not all of the water was evaporated from the sand, causing the recovered mass to be higher. It is possible not all of the water was evaporated from the sand, causing the recovered mass to be lower. While drying the NaCl, the liquid boiled and some splattered out of the evaporating dish, causing the recovered mass to be lower. While drying the NaCl, the liquid boiled and some splattered out of the evaporating dish, causing the recovered mass to be higher. There was no difference in recovered and original mass, so there is no difference to account for.