A compound is analyzed and determined to be 30.4% nitrogen and 69.6% oxygen. What is the empirical formula of the compound?

If anyone would be able to me out with these three questions it would be these are from the chem 2202 course.

How many molecules are in 6.0 moles of methane

Which of the following is the correct definition of chemical energy? a. energy an object has because of its motion or position b. energy resulting from the flow of charged particles, such as electrons or ions c. energy produced from the splitting of atoms d. energy stored in chemical bonds of molecules