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 the procedure , the patient was asked to state all of the words from the list that he or she could recall , and to identify the last word recalled from prior to the start of the procedure and the first word recalled from after the procedure was completed .
### Output Text:
After the procedure , the patient was asked to state all of the words from the list that he or she could recall , and to identify the last word recalled from prior to the start of the procedure and the first word recalled from after the procedure was completed . 