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: Twenty - five women were given raloxifene hydrochloride ( 60 mg / day ) plus calcium ( 500 mg / day ) .
### Output Text:
Twenty - five women were given <span class="chemical">raloxifene hydrochloride</span> ( 60 mg / day ) plus <span class="chemical">calcium</span> ( 500 mg / day ) . 