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 mortality for these Reye syndrome cases in Australia was 45 % as compared with a 32 % case - fatality rate in the United States .
### Output Text:
The mortality for these Reye syndrome cases in Australia was 45 % as compared with a 32 % case - fatality rate in the United States . 