Question

An air bag needs 60 dm3 of gas to inflate it at 25°C. Calculate: 1.1 the number of moles of N2 gas at 298 K required to inflate the air bag to a pressure of 1 atm. (7) 1.2 the number of moles of NaN3 required to produce this amount of gas (Hint: NaN3 reacts to produce Na(s) and N2(g). (5) 1.3 the mass of NaN3 required.

Answer 1

1.1)           If 24dm³= 1mole

60dm³=? 60/24

=2.5moles

1.2)           2NaN₃(s)=2Na(s) +3N₂(g)

Moles of NaN₃(s)=?

If 3=2.5moles

2=?

2×2.5/3

=1.667moles

1.3)           Mass of NaN₃(s)=?

Mass=moles × RMM

=1.667×65

=108.4g