Answer to Question #286436 in General Chemistry for LULU

Question

How do I know if the silica in the bag packed is saturated or can be used directly without preheating? (I know the case in the desiccator once the silica turn to pink it needs to be heated to reuse it again) how about the silica in the bag, how to know the condtion.

and if it needs to be heated, at what temperature should be heated in the oven and for how long?

Answer 1

Indicating and non-indicating silica gel can be mixed to help determining when the silica becomes saturated. Silica gel displays its full colour change when it is saturated by holding 8-10% of its weight in moisture; at that point the silica gel should be changed or regenerated