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: Participants completed a drug history questionnaire , Beck Depression Inventory , Barratt Impulsiveness Scale , Pittsburgh Sleep Quality Index , and Wechsler Memory Scale - Revised which , in total , provided 13 psychometric measures .
### Output Text:
Participants completed a drug history questionnaire , Beck Depression Inventory , Barratt Impulsiveness Scale , Pittsburgh Sleep Quality Index , and Wechsler Memory Scale - Revised which , in total , provided 13 psychometric measures . 