an example.
water is H2O
2 hydrogen, 1 oxygen
so the number to the right means how much of what is on the left.
so it looks like 2, because C2, but look at the 3 at the beginning. that means
3 (c2h4)
so 6 carbons, 12 hydrogen
the ratio of c2 to h4 doesn't change it's always 1:2.
but the 3 at the front is a different number relating to how much you have
