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: The goal of this study was to assess mitochondrial function and ROS production in an experimental model of cocaine - induced cardiac dysfunction .
### Output Text:
The goal of this study was to assess mitochondrial function and ROS production in an experimental model of <span class="chemical">cocaine</span> - induced cardiac dysfunction . 