When my kids were in 5th grade (public school), they had an average of 10 minutes, plus they needed to read 20 minutes a day, and since they played instruments they needed to practice. There was usually a spelling test every Friday, so Thursday nights we needed to study the spelling words, my oldest never studied since she knew them all by the end of the week, my youngest would study for 5 to 10 minutes. In addition, they would occassionally have a project that they needed to work on. If they spaced it out, they could spend 15 minutes a night on it. No, 2 hours is not normal.
Our school had a policy of no homework on weekends. I hated it and complained constantly to the teachers. He would assign a project on Monday or Tuesday and want it done on Thursday or Friday. I finally convinced him that working parents usually had time on the weekends to assist their children with these projects, take them to the library, give them internet access, and go shopping for supplies. If he assigned it on Thursday and it was due on Tuesday, it was the same amount of time and the child/parents could have an option of when to complete it.
There was never any "studying" for test. First of all, there weren't that many tests. Second, they knew the material and would just need to take a few minutes to review it.
I think you should have a conference with the teacher. At that level, he should not have that much homework. Is there as possiblility that he is not using the allotted time give to him in the classroom? Is he having difficulty in a certain subject? Would he benefit from having some homework help?