The air bags in cars are inflated when a collision triggers

The air bags in cars are inflated when a collision triggers te explosive decoposition of NaN4

2 NaN3 ---> 2 N + 3 N2

Calculate the mass of NaN4 required to fill a 127 L air bag. Assume the pressure in the car is 1.00 atm and the temperature of the resulting N2 produced is 85C.

Solution

Moles of N2 required

n = PV / RT

=> n = 101325 x 0.127 / 8.314 x 358

=> n = 4.3234 moles of N2

=> moles of NaN3 = (2/3) x 4.3234 = 2.88 moles

=> mass = 65 x 2.88 = 187.35 grams