you really are putting yourself at high risk if u leave it out. It worth 40% or above of your entire grade. Dont be stupid, u have 3 weeks till chemistry. Do yourself a favour and get it done. Don't worry you'll thank me later.
I don't think you should leave it out. It come every year as a question 2, question 6 and question 8 and sometimes it comes as 10 (a) question. This is a total of three from the six questions you have to do in the Leaving Cert. So maybe have a think about it.