Depends on whether it conveys what you want it to. Wikipedia simply states that a chapter is merely a "division" in a book, so it seems that it's all fairly arbitrary anyway.
Incidentally, I'm currently reading a book whose last chapter (minus the epilogue) is over a hundred pages - i.e. probably around 36,000 words - long. If it weren't for all that plot beforehand, it'd be a novella in its own right.