Ammonia and oxygen react to form nitrogen and water
4NH3 + 3O2 —> 2N2 + 6H2O

A) How many grams of O2 are needed to react with 13.6 g of NH3

B) How many grams of N2 can be produced when 6.50 g of O2 reacts?

C) How many grams of water are formed from the reaction of 34.0g of NH3?

If you can please show the equation on how to get the answer, Thank you in advance!