Use Avogadro's law to calculate volume.

Question

A sample of gas contains 0.140 mol of N₂(g) and 0.280 mol of H₂(g) and occupies a volume of 19.0 L. The following reaction takes place:

N₂(g) + 2H₂(g)N₂H₄(g)

Calculate the volume of the sample after the reaction takes place (assume temperature and pressure are constant).

_____L

Answer 1

N2(g) + 2H2(g) ==> N2H4(g)

0.140......0.280..........0.............Initial

-0.140....-0.280........+0.140.....Change

0..............0...............0.140.......Equilibrium

V1 / n1 = V2 / n2

V1 = initial volume = 19.0 L

n1 = initial moles = 0.140 + 0.280 = 0.420 mols

V2 = final volume = ?

n2 = final moles = 0.140 mols

Solving for V2, we have..

V2 = V1n2 / n1

V2 = (19.0 L)(0.140 mol) / 0.420 mol

V2 = 6.33 L