2NaN3(s) -> 2Na(s) + 3N2(g) The airbag has an envelop with a volume of 55L. One mole of gas occupies a volume of 83L. What is the mass of reactant needed for the system to work properly?

Question

Determine the mass of reactant needed for the air bag to work properly. Under the conditions of temperature and pressure inside a deployed airbag, one mole of gas occupies a volume of 83L. Final volume must be 55L

Answer 1

To find the mass of the reactant NaN₃ based on the volume of the airbag, do the following math:

Volume of airbag x Ratio of mole to gas volume x Mole ratio of the reaction x Molar mass ratio of the reactant

55L N₂ airbag x (1 mol N₂ / 83L N₂) x ( 2 mol NaN₃ / 3 mol N₂) x (65.01g NaN₃ / 1 mol NaN₃) = 28.72 g NaN₃ === rounded to 29g NaN₃ because of significant figures.

Let me know if you have additional questions,

I hope it helps,

Emilie

Answer 2

Hi Sam W.,

When I do these, I like to lay out the problem in the from of, "how many of what (?) = asked", then convert it into what is sought.

? g NaN₃ = 55 L, then convert with what we are given, 1 mol N₂ = 83 L N₂, 2 mols NaN₃ = 3 mols N₂, we need to calculate, # g = 1 mol NaN₃.

? g NaN₃ = 55 L * (1 mol N₂ / 83 L) * ( 2 mols NaN₃ / 3 mols N₂ ) * ( 65 g NaN₃ / 1 mol NaN₃ ) = 29 g NaN₃

Make sure I calculated the # g NaN₃ per mole correctly and check my multiplication/division.

I hope this helps, Joe