Formulae and Equations
The only thing I have found that might be useful is a interactive balancing equation exercise on the Creative Chemistry site:
There are also several shareware programs you could have a look at, but the only ones I found were all Windows-based, and I'm not going to include anything on this site which isn't open to everybody. The only other free animations I could find were either chemically flawed or not worth the bother.
The truth is that learning to write formulae and equations is something best done with a bit of paper and a pencil, and anything else is largely a distraction.
© Jim Clark 2017