Question

A 30 cm3 sample of nitrogen was reacted with a 60 cm3 sample of fluorine according to the equation
What is the volume of the gas mixture after the reaction, at constant temperature and pressure?

Answer 1

The equation is

N₂(g) + 3F₂(g) --> 2NF₃(g)

The mole (and volume) N₂ : F₂ ratio according to the equation is 1 : 3.

The actual ratio is 30 : 60 or 1 : 2, hence F₂ is the limiting reactant.

To calculate the volume of a gas mixture after the reaction, the volume of NF₃ and remaining N₂ should be determined.

V(NF₃) = 2/3 x V(F₂) = 40 cm³.

According to the equation, the volume of N₂ that reacted is 1/3 x V(F₂) = 20 cm³.

V_remaining(N₂) = V_total(N₂) - V_reacted(N₂)= 30 - 20 = 10cm³.

V_mixture = 40 + 10 = 50 cm³.

Answer: 50 cm³