Question

Sodium azide decomposes rapidly to produce nitrogen gas. 2 nan3(s) → 2 na(s) + 3 n2(g) what mass of sodium azide will inflate a 60.3 l airbag for a car to a pressure of 1.78 atm at 30.0 °c? (r = 0.08206 l×atm/mol×k)

Answer 1

We solve for n of N₂ gas from the ideal gas equation:

PV=nRT
n = PV/RT
n = (1.78 atm)(60.3 L)/(0.08206 L-atm/mol-K)(30 + 273 K)
n = 4.32 mol N₂

Through stoichiometric calculations,
Mol NaN₃ = 4.32 mol N₂ * 2 mol NaN₃/3 mol N₂ = 2.88 mol

Since the molar mass of sodium azide is 65 g/mol,

Mass = 2.88 mol * 65g/mol = 187.2 g NaN₃