Wordnet 3.0
ADVERB (2)
1. 
 with chemicals;"chemically fertilized"; 
2. 
 with respect to chemistry; 
- Example: "chemically different substances"- Example: "chemically related"
The Collaborative International Dictionary of English v.0.48:
Chemically \Chem"ic*al*ly\, adv.
   According to chemical principles; by chemical process or
   operation.
   [1913 Webster]
WordNet (r) 3.0 (2006):
chemically
    adv 1: with chemicals;"chemically fertilized"
    2: with respect to chemistry; "chemically different substances";
       "chemically related"