in JC you dont need to learn loads of formulae ? you only need like 4 , and try learn them off like, make them in to words, like instead of saying the letters C-a-C-o-3, say CaCo3, like 'cackle' in a posh way (caccko3) ygm? it helped me and my friends so i dunno might help you too :)
They can be confusing but i found them easy to learn last year. I'm in third year now, and we did a lot of chemistry last year so we had plenty of chemical equations and formulae to learn.
Some come in the logbook that you get but others it is much better to know. You will get a simple periodic table of elements (without the group and column numbers) in the exam so you don't have to learn off those (but it would be handier if you knew at least some of them). The chemical equations for the acid and base reaction, the air chapter ones and a couple of others could be asked so its best to revise those as much as possible.
good luck with ur revision!