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: Morphine 0 . 1 mg x kg ( - 1 ) iv was given for premedication and all patients were monitored with a noninvasive blood pressure monitor , ECG and pulse oximetry .
### Output Text:
<span class="chemical">Morphine</span> 0 . 1 mg x kg ( - 1 ) iv was given for premedication and all patients were monitored with a noninvasive blood pressure monitor , ECG and pulse oximetry . 