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: Ammonia coma was produced in rats within 10 to 15 minutes of an intraperitonealinjection of 1 . 7 mmol NH4CL .
### Output Text:
<span class="chemical">Ammonia</span> coma was produced in rats within 10 to 15 minutes of an intraperitonealinjection of 1 . 7 mmol <span class="chemical">NH4CL</span> . 