1. The problem statement, all variables and given/known data I have H2SO4 + BaCl2 → and need to figure out what it will create. 2. Relevant equations Now I don't know how to figure out ionic charges or the rules of writing ions/chemical equations. I mean tried to break that up in class today into separate ions and my teacher said you can't have h2 all by itself... why is that? 3. The attempt at a solution I'm at this so far: 2H + SO4 + Ba + Cl2 → H2 + SO4 + Ba + Cl2 → How do I know how to write certain things, for instance my teacher also said you cant write 20, it needs to be o2 why is this? Also how do I determine ionic charges of things?