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: Temocapril ( 8 mg / kg / day ) was administered to the rats which were killed at weeks 4 , 14 or 20 .
### Output Text:
<span class="chemical">Temocapril</span> ( 8 mg / kg / day ) was administered to the rats which were killed at weeks 4 , 14 or 20 . 