Question

LUSSAC'S LAW
1. Nitrogen reacts with hydrogen to give ammonia. Calculate the volume of the ammonia gas formed when nitrogen reacts with 6 litres of hydrogen. All volumes measured at s.t.p.

Answer 1

PV = nRT

P = 1 atm

T = 298K

R = 0.08206 L·atm·mol⁻¹·K⁻¹

V = 6 ltr

n = ?

Using above values and putting them in formula we get

n = 0.25

N₂(g) + 3H₂ → 2NH₃

1 mole of Nitrogen reacts with 3 moles of hydrogen

So,

0.084 moles of Nitrogen reacts with 3 moles of hydrogen

Using same equation of PV = nRT

This time we know "n" and like to find V for nitrogen

V = nRT/P = 0.084 * 0.08206 * 298 / 1 = 2 ltr

Solution 2 ltr.