Los chicanos son todas aquellas personas que apesar de su ciudadania en Los Estados Unidos sus origenes son Mexicanos, es decir sus padres, abuelos, bisabuelos provenian de Mexico.
In Spanish a personal A used when the direct object is a person
Example: Brooke llama A Elsa
In English this means Brooke calls Elsa
But in Spanish it is being use mostly at a person but can also be use at an object
Hope this helps :3