please help me with the following problems. please also work them out so i can have a better understanding. thank you!

2. A compound contains nitrogen atom(s) and cxygen atom(s) and has a formula mass of 44.02 amsu. What is its molecular formula? 3. What is the molecular formuls of the compound coesisting of aluminam ion(s) and sulfite ion(s) with a formula mass of 294.15 amat? 4. What is the formula, symbol, and charye for each of the following ions? a. Hydrogen carbonate ion b. Nitrate ion v. Ammonium ion d. Dichromate ion c. Iron (III) ion f. Manganese (VI) ion