solving for a gaseous reactant

Question

Write a balanced chemical equation, including physical state symbols, for the decomposition of solid sodium azide (NaN3) into solid sodium and gaseous dinitrogen.

Suppose 22.0 L of dinitrogen gas are produced by this reaction, at a temperature of 11.0 C and pressure of exactly 1 atm. Calculate the mass of sodium azide that must have reacted.

Answer 1

2 NaN3(s) ——> 2 Na(s) + 3 N2(g)

 

PV = nRT  ——> n=PV/RT

n = 1atm*22L/(0.08206*284K)

n = 0.944 mol N2

 

MW or MM of NaN3 = 23+14*3 = 65 g/mol

(0.944 mol N2) x (2 mol NaN3 / 3 mol N2) x (65g NaN3 / 1 mol NaN3)

 

mass of NaN3 = 40.9 g