N2 + 3H2 = 2NH3
First, we need to determine the number of N2 moles:
n(N2)=N/NA=2.5 x 10²¹ / 6x10²³ = 0.0042 mole
According to the equation of the reaction of ethane combustion, nitrogen and ammonia have following stoichiometric ratio:
n(N2) : n(NH3) = 1 : 2
n(NH3) = 2xn(N2)
n(NH3) = 2x0.0042 = 0.0083 mole of NH3 will be produced in the reaction