sevenperforce wrote:I can balance equations but only if I already know both sides. Trying to find the following products:
It's been a while since I have done chemistry at such exam/test-level, but I presume you're expected that in...
Na2S2O5 + O2 = ?
...you're supposed to assume full combustion.
Thus (correcting some of the notation) Na2
O + SO2
But then you need to put the 'big' numbers in to balance it, which it sounds like you can do.
The other ones aren't obvious combustions (without checking ion affinities), but look to be suitable sources for ion-group swapping, reductions, etc. I'm almost certain that this is the kind of thing you get given as homework after being specifically told "a disulphite compound will typically react with these varieties of compounds to create such'n'such other type of compound", which should be all the clue you need to run with the rest.
But I await a chem-nerd telling me off for assuming
that the first is a disintegrating oxidation, even, rather than prefering to become an even more richly oxygenated metasulphide/ite/whatever, or something else I haven't thought of yet.