# "Sodium azide", NaN_3, is used in automobiles to fill air bags: (i) is this an example of chemical change; (ii) is the mass of the products equal to the mass of the reactants; and (iii) could a 83.0*g sodium azide give rise to a volume of 36*L?

Dec 28, 2017

Yes, yes, yes....

#### Explanation:

So we gots....

$2 N a {N}_{3} \left(s\right) \rightarrow 2 N a \left(s\right) + 3 {N}_{2} \left(g\right)$

We could separate this reaction out into half equations...

${\underbrace{N {a}^{+} + {e}^{-} \rightarrow N a \left(s\right)}}_{\text{reduction half equation}}$ $\left(i\right)$

${\underbrace{{N}_{3}^{-} \rightarrow \frac{3}{2} {N}_{2} \left(g\right) + {e}^{-}}}_{\text{oxidation half equation}}$ $\left(i i\right)$

And so we add $\left(i\right)$ and $\left(i i\right)$ in the usual way to eliminate the electrons....

$N a {N}_{3} \left(s\right) \rightarrow \frac{3}{2} {N}_{2} \left(g\right) + N a \left(s\right)$

And so we start with a solid reagent, the nitride salt, and electrical ignition gives rise to A GASEOUS PRODUCT...i.e. dinitrogen....and each $83 \cdot g$ mass of sodium nitride gives rise to a volume of approx. $36 \cdot L$ dinitrogen, that inflates the bag, and hopefully cushions your nut when it strikes the steering wheel...