In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: The average score according to the Children ' s Hospital of Eastern Ontario Pain Scale was 6 . 4 points ( range , 5 to 10 points ) , reflecting minimal or no pain during fracture reduction .
### Output Text:
The average score according to the Children ' s Hospital of Eastern Ontario Pain Scale was 6 . 4 points ( range , 5 to 10 points ) , reflecting minimal or no pain during fracture reduction . 