Answer :
Use the mole ratio: 2 moles of NaN3 : 3 moles of N2
you have : 0.21 moles of NaN3 : x moles N2
Cross multiply: you get 0.3 moles for N2
To find the mass= # of moles * molecular mass
0.3 * 28
= 8.4g
you have : 0.21 moles of NaN3 : x moles N2
Cross multiply: you get 0.3 moles for N2
To find the mass= # of moles * molecular mass
0.3 * 28
= 8.4g