I am in portland oregon. i want to know how many hours a day i can be scheduled?,

In most states,the labor laws vary depending on the type of work & age of the employee,contact your states dept of labor either online or better yet,give them a call!

If you are 18 years old the law is they have to give you 8 hr. in between shifts or they have to pay you time and 1-half

You can be scheduled up to 24 hours in a given day in most industries and receive no overtime pay, and there is no provision for a gap in between hours worked. The only time you are eligible for overtime pay is if you work over 40 hours in a seven day work week, as determined by your employer.

However, there may be exceptions to those rule depending upon union/nonunion rules, and industry specific rules.