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: After 12weeks , animals were euthanized , and CaCl ( 2 ) - treated , CaCl ( 2 ) - untreated ( n = 12 ) and NaCl - treated aortic segments ( n = 12 ) were collected for histological and molecular assessments .
### Output Text:
After 12weeks , animals were euthanized , and <span class="chemical">CaCl ( 2 )</span> - treated , <span class="chemical">CaCl ( 2 )</span> - untreated ( n = 12 ) and <span class="chemical">NaCl</span> - treated aortic segments ( n = 12 ) were collected for histological and molecular assessments . 