Question

HI

I'd like to ask if anyone would give me a website that provides quizes or questions on how to balance a formula with the symbols.

Example

iron ( iii) oxide

It will become Fe3O2 but when we change it

Fe203 is the right answer

this sort of questions

Answer 1

http://www.fordhamprep.org/gcurran/sho/sho/lessons/lesson53.htm

see the links at the end of that tutorial.