Question

If you have 39 g of sodium azide in an air bag [2nan3 (s) -> 2na (s) + 2n2 (g)], then how many molecules of nitrogen gas will it make at stp?

Answer 1

2nan3 -->2na +3h2
calculate the moles of nan3 =39/65=0.6 moles
the reacting ratio of nan3 to h2 is 2:3 therefore the mole of h2 formed is ( 0.6 x3 )/2=0.9 moles
using the avogadros law
1 mole=6.02 x 10^23, what about 0.9 moles
=0.9 x ( 6.02 x10^23)=5.418 x 10^23

Answer 2

Sodium Azide in an air bag = 39g
Converting the given grams in to moles, that is 1 mole = 65 grams
Sodium Azide in moles = 0.6
From the equation there are 2 moles of Sodium Azide and there are 3 moles of N
Calculating the N2 in moles = (3 x 0.6)/2 = 0.9 moles of N2
Calculating the molecular mass of N = 0.90 x 6.022 x 10^23 = 5.42 x 10^23.