Solid sodium azide (NaN3) is used in air bags to fill them quickly upon impact. The solid NaN3 undergoes a decomposition reaction to produce Na(s) and N2(g).

Question

a. Provide the balanced equation for the decomposition of NaN3.
b. What mass, in grams, of NaN3 is needed to fill the air bag of a vehicle to a volume of 79.0 L at 32.0 °C and 0.97 atm?

Answer 1

2NaN3 ==> 2Na + 3N2

Use PV = nRT and solve for n = mols N2 gas at the conditions listed.
Using the coefficients in the balanced equation, convert mols N2 to mols NaN3. Then convert mols NaN3 to grams. g = mols x molar mass.