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 she had received a total of only 0 . 9 mg droperidol , a syringe containing diamorphine only was substituted and her unease resolved completely .
### Output Text:
After she had received a total of only 0 . 9 mg <span class="chemical">droperidol</span> , a syringe containing <span class="chemical">diamorphine</span> only was substituted and her unease resolved completely . 