Is obtaining a MS degree in Chemistry useful to strengthen your CV if you wish to apply to a top PhD program in Chemistry? I got admitted to a small MS program in the US with an assistantship and I still have not decided if I should accept the offer or not. The reason is that I want to pursue a PhD and build an academic career in the field of Chemistry. However, I come from a small institution in a developing country with little research, so I cannot just apply to a top graduate program such as Berkeley or Harvard because I would be in serious disadvantage in comparison to the hundreds of other applicants which have publications and vast research experience.
In your opinion, is obtaining a MS degree in an American institution, even though it is in a very small program, something that would improve my chances of being accepted into a decent PhD program in the future?

I could also try those smalls PhD programs in institutions ranked below the top 100 (according to THE or QS) but I heard from a lot of people that a PhD in such an institution would add nothing to your career, since there are many PhDs graduating from top institutions and it is already hard for them to get a job, so your chances of succeeding either in an academic or industrial career would be quite low, and most of them have to find something else to do (work at a home depot, open a clothing shop etc, just kidding).
Short answer is yes, you probably should take it or a position like it if you want a PhD from a top US school. It sounds like you don't have many or any papers as a coauthor and your current school's reputation is unknown. So, getting a Masters from a US school with a good reputation, even though it may be a smaller institution could give your application a boost. Also, you will want to see if you can get an internship during the summer with a major research institution while you're doing it. That will open many more doors than the Masters alone.