Question

Nitrogen, 45.0 moles, and Oxygen, 145.0 moles, react according to the equation below, what remains assuming complete reaction?

2N₂ (g) + 5O₂ (g) ---> 2N₂O₅ (g)

Answer 1

we have the Balanced chemical equation as:

2 N2 + 5 O2 ---> 2 N2O5

2 mol of N2 reacts with 5 mol of O2

for 45 mol of N2, 1.125*10^2 mol of O2 is required

But we have 1.45*10^2 mol of O2

so, N2 is limiting reagent

we will use N2 in further calculation

From balanced chemical reaction, we see that

when 2 mol of N2 reacts, 5 mol of O2 reacts

mol of O2 reacted = (5/2)* moles of N2

= (5/2)*45

= 1.125*10^2 mol

mol of O2 remaining = mol initially present - mol reacted

mol of O2 remaining = 1.45*10^2 - 1.125*10^2

mol of O2 remaining = 32.5 mol

Answer: 32.5 mol of O2 remains