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: However , administration of nefiracetam during training completely reversed the amnesia induced by apomorphine at the 10h post - training time and the converse was also true .
### Output Text:
However , administration of <span class="chemical">nefiracetam</span> during training completely reversed the amnesia induced by <span class="chemical">apomorphine</span> at the 10h post - training time and the converse was also true . 