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: After 15 min , mice were evaluated for their open - and closed - arm time and entries on the EPM for a 10 - min session .
### Output Text:
After 15 min , mice were evaluated for their open - and closed - arm time and entries on the EPM for a 10 - min session . 