Question

Consider the equation: 2 nan3 (s) 2 na (s) + 3 n2. what is the mass of nan3 needed to produce 17.2 l nitrogen at stp?

Answer 1

The  mass  of NaN3  needed  to produce 17.2  L  nitrogen   at  STP is  calculated as  follows

find the  moles of N2   produced  at  STP
At  STP  1mole  of  gas =  22.4  L ,  what about  17.2 L  of  nitrogen

by cross  multiplication

= (1 mole x17.2  L)/ 22.4 L= 0.768  moles

2NaN3 =2Na  +3 N2
by   use of  mole ratio  between NaN3  to N2  (2:3) the  moles  of NaN3  =  0.768  x2/3 =  0.512  moles  of NaN3

mass of NaN3  is therefore =moles of NaN3  xmolar  mass of NaN3

=0.512moles  x 65 g/mol =33.28 grams  of NaN3