10. Airbags in automobiles contain the compound sodium azide, NaN3. A crash triggers the decomposition reaction of NaN3 to produce nitrogen gas, which causes the airbag to inflate. How many grams of NaN3 are required to produce 90.00 grams of N2 gas at STP in the following, unbalanced reaction?

The answer is 139.1 g of sodium azide.

Explanation:

To solve this question we need to find first the stoichometry of the reaction to find the moles involved.

1. The balanced formula:

2NaN3 ⇒ 3N2 + 2Na

(important: the nitrogen is a gas, therefore, is always diatomic N2)

2. The moles:

We need to convert the 90 g of N2 into moles to know the relations of amounts between the other compounds in the chemical equation

90 g of N2 x (1 mol of N2 / 28 g of N2) = 3.21 mol of N2

3. Stoichometry:

The relations of the amounts of moles of N2 and NaN3 using the balanced formula

3.21 mol of N2 x (2 mol of NaN3/3 mol of N2) = 2.14 mol of NaN3

4. Moles into grams

then to answer the question we convert the moles value of NaN3 into grams of NaN3

2.14 mol of NaN3 x (65 g of NaN3 / 1 mol of NaN3) = 139.1 g of NaN3.

and this is the answer of the question.