"famous for her work with immigrants at Chicago's Hull House" is the appositive
Explanation:
An appositive phrase adds information to a sentence. You know it is the appositive when you can remove it, and the rest of the sentence still makes sense. What you have left is, "Addams was also well known for her work on women's rights." Also, appositives are set apart from the rest of the sentence with commas.
