Question

0.010 mol nitrogen and 0.0250 mol oxygen

Answer 1

empircal formula

Answer 2

n(N) : n(O) = 0,01 : 0,025
now divide those two nubers with smaller one
n(N) : n(O) = 1 : 2,5
and now you need to get a whole numbers by multiplying with 2,3,4... until you get the whole number
n(N) : n(O) = 1 : 2,5 / *2
n(N) : n(O) = 2 : 5

and formula is N2O5