if there is another chemistry class at your school who are doing a topic other than chem of art, then there is no reason why you couldnt be able to do the same topic as the other class. I would presume that during chem class time you would just study your own option topic and you would do assessments with the other class. seems simple
but if you were doing a totally different topic, talk to your teacher or science co ordinator and see if they can help you. if you do the latter be sure to be clear that you absolutely do not want to do chem of art, otherwise the conversation can very easily lead into "why dont you try to do the chem of art topic first before you go and do a totally different topic?", which wouldnt help your cause