Chemical equations.. help balancing..?

Question

Li + O2 ---> Li2O

Answer 1

The balanced equation is: 4Li + O2 = 2Li2O.  Li has an oxidation number of +1 and oxygen is -2 so it takes 2 lithiums for every oxygen.  To balance, add coefficients until you have the same number of each element on both sides of the equation.  To double check yourself, assuming your subscripts are correct, go to this web site and it will balance your equations for you:

http://adomas.org/bceq/