Is there a site where I can type the reactants of a chemical reaction and it shows me the products

I really, really want to see what "FeSO4(aq) + H2SO4 + KMnO4 -->" gives.

To answer, your first query, "no", to my knowledge, there is no single website which will tell you the products to chemical reactions. But there is a way to do that. Google. For instance, had you searched on "FeSO4 + KMnO4", then you will get many hits which include the correct equation.

The reaction, by the way, is a redox reaction between Fe2+ ions and MnO4- ions. All the other ions are spectator ions with the exception of the H+ of the acid. In order for MnO4- to be reduced to Mn2+, the solution must be acidic.

Here is the actual reaction (unbalanced)
Fe2+ + KMnO4- + H+ --> Fe2+ + Mg2+ + H2O

Balance the redox reaction using the "half-reaction" method
5(Fe2+ --> Fe3+ + 1e-)
8H+ + MnO4^- + 5e- --> Mn2+ + 4H2O
----------------------------- -----------------------------
5Fe2+ + MnO4^- + 8H+ --> 5Fe3+ + Mn2+ + 4H2O

Should you actually need the "molecular equation", then simply add in the spectator ions, but be sure to include the state symbols.

10FeSO4(aq) + 2KMnO4(aq) + 8H2SO4(aq) --> 5Fe2(SO4)3(aq) + 2MnSO4(aq) + K2SO4(aq) + 8H2O(l)

Your own Chemistry text will have it - may be in the split form:
KmnO4/H2SO4 -----> HMnO4 ----> H2MnO4 + O , etc..... .Pl see in detail. I do not spoon feed , as this is an important reaction to be known, & the experiments are also to be conducted !

10FeSO4 + 8H2SO4 + 2KMnO4 -----> K2SO4 + 2MnSO4 + 5Fe2(SO4)3 + 8H2O

i dont think there is any such website ....you have to learn the properties ....like here KMnO4 in acidic medium oxidises ferrous sulphate to ferric sulphate